October 19, 2021

Did the wild dromedary break the rule of miniaturisation in Arabia?

In a previous Post (October 02, 2020, https://www.inaturalist.org/journal/milewski/archives/2020/10), I pointed out a pattern which is hard to explain biogeographically or ecologically. This is the remarkably consistent miniaturisation in the wild fauna of large mammals on the Arabian Peninsula.

However, there may be one exception: the extinct wild ancestor of the dromedary (Camelus dromedarius). This occurred on the 'horn' of Arabia where Dubai now stands (https://upload.wikimedia.org/wikipedia/commons/c/cd/United_Arab_Emirates_%28orthographic_projection%29.svg). It seems to have lived not in the inland desert but on a mangrove-edged coastal strip on the Strait of Hormuz (https://www.pnas.org/content/113/24/6707 and https://en.wikipedia.org/wiki/Strait_of_Hormuz).

The reason to think that the wild dromedary was not miniaturised is that its domestic descendent far outsizes any species of ungulate indigenous to Arabia or the Sahara - or for that matter the Sahel (Oryx dammah, adult female body mass less than 140 kg, https://en.wikipedia.org/wiki/Scimitar_oryx).

Consider the average body mass of adult females of the dromedary. This is about 500 kg according to Tibary and Anouassi (1997, pages 2-4 in 'Theriogenology in Camelidae: anatomy, physiology, pathology and artificial breeding'). The figure ranges from 350 kg in parts of Kenya and Sudan to 640 kg in Syria.

The corresponding figures for the bactrian camel (Camelus bactrianus, page 10 of same reference) is about 550 kg, ranging from 480 kg in Mongolia to 650 kg in Kyrgystan.

The fact that the bactrian camel is the more massive is unsurprising because it is adapted to seasonally cold climates (https://en.wikipedia.org/wiki/Bergmann%27s_rule).

This climatic difference applies despite the bactrian camel and the dromedary having both been domesticated in the Iranian region.

Whereas the dromedary was domesticated in a warm coastal semi-desert just south of Iran and across the Strait of Hormuz, the bactrian camel was domesticated in a seasonally cold inland semi-desert in northeastern Iran, about 750 km from this strait.

If the wild ancestor of the dromedary was as massive as the domestic form so closely associated with Arabian culture, then this would break the rule of miniaturisation in Arabia. At about 500 kg, the dromedary is at least fourfold more massive than the next-largest ungulate indigenous to Arabia, namely the extinct Syrian wild ass (Equus hemionus hemippus, https://en.wikipedia.org/wiki/Syrian_wild_ass).

However, it remains possible that the body size of the dromedary is partly owing to the process of domestication - by a combination of hybridisation and selective breeding in prehistoric times.

It seems that artificial hybridisation with the bactrian camel began from the start of the domestication of the dromedary (https://iranicaonline.org/articles/camel-sotor#:~:text=The%20Iranians%20would%20thus%20have,it%20was%20probably%20not%20numerous.).

This was practicable partly because the bactrian camel had already spread, by that time, to southeastern Iran - where it was separated from the site of domestication of the dromedary by little more than a ride in a boat. It seems to have been easy enough, even four thousand years ago, to transport males of the bactrian camel to what is now the United Arab Emirates across the Strait of Hormuz.

Any systematic hybridisation would have doomed the dromedary in the strict sense of a distinct species. However, it might have facilitated the subsequent selective breeding of increased body size, from early in the process of its domestication.

The incentive for boosting the body size of the dromedary would have been to utilise it farther inland, where viable thresholds of drought-tolerance, mobility, production of milk and capacity for labour all depended on body size. And in view of the flexibility of body size in other species of domestic mammals it seems possible that the body mass could have been doubled within a few centuries.

The Syrian wild ass was diminutive and may also have been domesticated, at least partly and for a limited period (contrary to Wikipedia). There is no evidence of any artificial boosting of body size in its case, but its roles in domestication were different from those of the dromedary.

So, which is more likely for the ancestral, wild dromedary of Arabia: that its adult female body mass was about 500 kg from the start or that it was only about 250 kg until an artificial and rapid enlargement which has left no trace of the original diminutive form?

Posted on October 19, 2021 09:51 AM by milewski milewski | 2 comments | Leave a comment

October 17, 2021

Some reasons why the llama spits

The llama (Lama glama, https://en.wikipedia.org/wiki/Llama), as everyone knows, 'spits' (https://www.youtube.com/watch?v=gF4el-h3Yic and https://www.youtube.com/watch?v=nDi6NPQPAtI and https://www.agriculture.com/family/living-the-country-life/why-llamas-and-alpacas-spit and https://ramshornllamas.com/why-do-llamas-spit-and-how-to-stop-it/).

However, what may not be generally realised is how this relates to the combination of touch-aversion and hornlessness which characterises its wild ancestor, the guanaco (Lama guanicoe, https://en.wikipedia.org/wiki/Guanaco).

Spitting in the llama and the guanaco differs from spitting in humans, and may alternatively be described as non-nasal sneezing (https://www.youtube.com/watch?v=A_6XHB8D9vQ and https://www.facebook.com/watch/?extid=SEO----&v=566353500905689 and https://www.youtube.com/watch?v=AUQiP4FgzDQ and https://www.youtube.com/watch?v=o8cNLVD5pLo and https://www.jukinmedia.com/licensing/view/982504 and https://www.youtube.com/watch?v=bKkNyhq6EHo and https://www.youtube.com/watch?v=rjgDunX2SQk and https://www.youtube.com/watch?v=1bpJl1l3-K8 and https://www.youtube.com/watch?v=OeQsOxeiHjg).

A jet of droplets and aerosol is sprayed with surprising velocity and over a surprising distance while the mouth is only slightly open (https://www.youtube.com/watch?v=HszBEIn7EPo and https://www.facebook.com/watch/?v=4806245422755943).

The substance jet-sprayed is various combinations of saliva and stomach contents (https://www.youtube.com/watch?v=XLJpxhGmtH4). The composition of the 'spit' seems less important than the physical insult delivered. In other words, spitting in the llama and the guanaco does not seem to be a case of chemical defence as much as an unusual form of physical threat.

It is tempting to suggest that we call this behaviour 'agonistic sneezing', which sometimes includes 'vomit-sneezing'. However, this is also unsatisfactory because the llama and the guanaco breathe exclusively through the nose, and their true sneeze is purely nasal. Such are the difficulties of the English language for precise descriptions in science.

Spitting in the llama seems to function similarly to the gesturing that is performed in other ungulates by means of lowered horns or antlers (or lowered forehead in the case of females of many species), or flailing fore hooves. Because the llama and the guanaco lack both head-adornments (at all) and hooves (in a strict sense), and their fang-baring displays are limited by the small size of their caniniform teeth (https://shadyufo.tumblr.com/post/165100306068/what-are-the-differences-between-llama-and-alpaca), it is reasonable that the head might be used in this alternative way in communication.

On page 75 of her book 'Llamas and alpacas: a guide to management' (2006, The Crowood Press), Gina Bromage states: "Llamas and alpacas...express defiant disapproval by spitting. If they wish only to warn, then often they will spit past or away from the other animal, but if they are really angry, they will spit directly at it...Sub-dominant animals rarely dare to spit at the dominant one...Laid-back ears...always precedes spitting".

Also informative is what Bromage writes on page 16: "A well-brought-up llama or alpaca would never deliberately spit at a person, any more than a well-brought-up dog or a horse would bite. Spitting is something that camelids properly reserve for squabbles amongst themselves. However, it is possible accidentally to get caught in the crossfire during a dispute among them. The other circumstances in which people are on the receiving end is where the animal concerned has not been properly trained to respect humans, and then, just as a rogue dog or horse might bite, a llama or alpaca might spit".

To understand these peculiarities, it may help to realise that the llama and the guanaco are among the most touch-averse of ungulates. There is no caressing behaviour in these species, regardless of age or sex. This applies even to maternity: the mother does not clean the newborn, which is left to dry off by itself.

So, although spitting in the llama is not only defensive but also partly aggressive, its meaning seems in certain situations to be 'Respect my personal space!'

Bromage states on pages 79-80: "Alpacas and llamas do not indulge in mutual grooming...they never lick, nibble, tickle or rub each other for mutual benefit (e.g. parasite removal) or pleasure. Even newly delivered mothers do not lick their babies. The effect of this is that the touch of another animal or human is always unwelcome...Llamas and alpacas cannot help having a step-away reflex...Their handlers must understand that to tolerate touch and not be alarmed or distressed by it...it has to overcome a very deeply rooted sense of alarm".

This syndrome is so strongly developed in the llama that, if the infant is subjected to cuddling by humans (e.g. https://www.startribune.com/minnesotans-are-hugging-llamas-as-pandemic-pick-me-up/600037226/ and https://www.airbnb.com.au/experiences/882431?_set_bev_on_new_domain=1634612225_ZGViZDI5MTY4ZDcz&modal=PHOTOS&modalItem=767209842), it grows up so spoilt that its manners are permanently lost through adulthood. To give the infant physical affection is effectively to abuse it.

This inadvertent abuse tends to be terminal for the pet because the results are too dangerous for humans. Individuals of the llama that have been cuddled as infants may have to be killed once adult. This is because they are inclined to inflict on humans not only spitting but also the real violence of kicking, biting and trampling.

Posted on October 17, 2021 10:32 PM by milewski milewski | 6 comments | Leave a comment

October 15, 2021

The dromedary as a humping mule

Everyone knows that mules are a vigorous hybrid between female horse (Equus caballus) and male donkey (Equus asinus), and that the dromedary (Camelus dromedarius, https://en.wikipedia.org/wiki/Dromedary#Relationship_with_humans) is the form of livestock most suited to drought. However, what many may not realise is how similar mules and the dromedary are in various ways.

The first, obvious, similarity is in body mass: both weigh preferably more than 400 kg when adult. This size, combined with hybrid vigour and the natural endurance derived from ancestors adapted to semi-arid conditions, makes both mules and the dromedary excellent beasts of burden.

A far less obvious similarity is that both are interspecific hybrids (see https://pastoralismjournal.springeropen.com/articles/10.1186/s13570-020-0159-3).

The first generation of hybrids between the dromedary and the bactrian camel (Camelus bactrianus) has only one hump but tends to be more vigorous than either parent.

And, as in the case of mules, the hybrids cannot practicably be bred among themselves to perpetuate this vigour. As everyone knows, mules are by definition infertile hybrids. For camels there is no such infertility but the hybrid vigour tends to be lost by the second generation anyway (https://iranicaonline.org/articles/camel-sotor#:~:text=The%20Iranians%20would%20thus%20have,it%20was%20probably%20not%20numerous.).

Because hybridisation between the two ancestral species of camels was practised from the start of the domestication of the dromedary, all populations of what is now classified as the dromedary probably contain genetic modifications from the bactrian camel. The most common sign of this may be long fur on the neck of the dromedary (https://www.inaturalist.org/observations/38474885), which belongs to the bactrian camel rather than the heat-tolerant wild ancestor restricted to Arabia.

Furthermore, as in mules, the hybridisation in camels is most effective with a particular species as the father.

It is best for males of large-bodied breeds of the donkey to be mated with females of the horse, because the mules thus produced are large-bodied. In the case of camels, it is best for males of the bactrian camel to be mated with females of the dromedary. This is because females copulate while lying on their bellies, and the rear hump of the bactrian camel tends to obstruct the mating squat of males of the dromedary.

Both mules and the dromedary are more difficult to breed than most domestic ungulates. And in both cases this is partly because of complications in mating, and partly because the reproductive process is slower than in true ruminants such as oxen (Bos spp.).

In both cases, mating needs to be supervised. The horse, even when in oestrus, finds the donkey so sexually unattractive that some artificial forcing is necessary. In the dromedary, breeding is inconveniently seasonal, rutting males can attack the mother's previous offspring, libido can be lacking, and successful copulation is needed to induce ovulation in the first place (https://www.sciencedirect.com/science/article/abs/pii/0378432087900492 and https://www.researchgate.net/publication/275250659_Male_camel_behavior_and_breeding_management_strategies_How_to_handle_a_camel_bull_during_the_breeding_season and http://www.veterinaryworld.org/Vol.2/February/Reproduction%20in%20Camel.pdf).

Equids have long gestation and a prolonged juvenile period, and this is even more limiting for the dromedary, which gestates for 13 months, first breeds at four years old, and can produce at most one offspring every two years (https://www.sciencedirect.com/science/article/pii/S1658077X20300709).

In compensation for the slow reproduction of equids and particularly camelids, mules and the dromedary are both surprisingly long-lived. The dromedary has a working life fourfold longer than that of the average ox (https://en.wikipedia.org/wiki/Ox), while carrying or pulling twice the load, locomoting more rapidly, working more frequently, and being able to forgo drinking for longer.

Both mules and the dromedary can be kept on food too poor for the horse or oxen. This is partly because the donkey is far better-adapted than the horse to eat fibrous, dead material, and partly because camelids have a digestive system less specialised, and thus less demanding and more versatile, than that of oxen and other true ruminants.

Whether mules or the dromedary were utilised by early civilisations was not necessarily dependent on climate. For example, in ancient Egypt and the Levant of the Old Testament it was mules that were prized for two thousand years, before their roles were largely usurped by the dromedary (https://www.mulemuseum.org/history-of-the-mule.html). It was only at this later stage that the latter species (or, strictly speaking, hybrid) was recruited from nearby Arabia for general service in farming, commerce and warfare in Egypt and the Levant.

Posted on October 15, 2021 09:03 PM by milewski milewski | 6 comments | Leave a comment

October 14, 2021

Why Eucalyptus erythrocorys tends to self-amputate in cultivation

Eucalyptus erythrocorys (https://apps.lucidcentral.org/euclid/text/entities/eucalyptus_erythrocorys.htm and https://twitter.com/eucalyptaus/status/1168440927628795904 and https://www.ecovoice.com.au/the-illyarrie-wins-eucalypt-of-the-year-2020/ and http://anpsa.org.au/e-ery.html and https://alchetron.com/Eucalyptus-erythrocorys) has large blooms: bright yellow and with exotic-looking red opercula (https://www.inaturalist.org/observations/70992084).

This makes for a cheerful -even spectacular - appearance as summer becomes autumn in the mediterranean-type climate.

So it is unsurprising that this species has become a horticultural favourite as a large shrub or small tree (https://www.bgpa.wa.gov.au/about-us/information/our-plants/plants-in-focus/eucalyptus-erythrocorys). It is planted in gardens and along streets in Australia (particularly in the west) and in the similar climate of southern California.

However, cultivating the species in this way (https://cals.arizona.edu/yuma/plant_index/eucalyptus_erythrocorys.htm and https://www.eranurseries.com.au/eucalyptus-erythrocorys) brings the practical disadvantage that the several boles of each individual plant tend to grow at angles, not upright.

As a result of this leaning tendency, top-heaviness often results in partial collapse. One of the boles suddenly breaks, felling that part of the crown and its growing foliage in what looks like spontaneous auto-amputation.

Now, everyone knows that various species of eucalypts, which grow naturally as large trees, have a disconcerting habit of suddenly dropping large branches (https://treesafe.com.au/blog/tree-removal/eucalyptus-trees-dangers/ and https://sydneytreeremovals.com.au/tree-facts/widow-maker-gum-trees-clear-deadwood/). It is understandable that tall trees would benefit from getting rid of redundant lower branches and dead sticks, but what is noteworthy about eucalypts is that the branches are usually shed with the foliage still growing.

The fact that various species of eucalypts spontaneously - and dangerously - jettison branches in a state of apparent vitality has led to the term 'self-pruning' (https://en.wikipedia.org/wiki/Cladoptosis).

Seen in this context, the proneness of cultivated E. erythrocorys to partial collapse seems incongruous. This is because, on this relatively small plant, such a large proportion of the stem system is 'shed' that the action resembles not self-pruning as much as an unsuccessful attempt at suicide.

Curious about this apparently maladaptive behaviour, I visited the plant in its natural habitat near the coast south of Dongara in southwestern Western Australia (https://apps.lucidcentral.org/euclid/text/entities/eucalyptus_erythrocorys.htm and https://en.wikipedia.org/wiki/Dongara,_Western_Australia and https://twitter.com/RichardMcLellan/status/1168669607059570689/photo/1). Here E. erythrocorys is locally dominant on ridges of coastal limestone, with a heathy understorey (see photo no. 12 in http://ianfrasertalkingnaturally.blogspot.com/2014/01/i-love-sunburnt-country.html).

What I noticed immediately is that, in its natural state, E. erythrocorys is more like a mallee (https://en.wikipedia.org/wiki/Mallee_(habit)) than it appears to be in the suburbs or in photos singling out the more statuesque specimens in the wild (e.g. https://www.inaturalist.org/observations/42711339). In nature, each individual usually has more than six stems emerging at ground-level even if the lignotuber, so typical of mallees, is not particularly well-developed.

This brought me to the realization that the growth-form encouraged in cultivation is different from the wild, multi-stemmed one. Gardeners, ignorant of the natural shape of the plant, understandably tend to cull the stems to a few which resemble boles of a (small) tree.

Closer examination distinguished E. erythrocorys from all the other species of mallees with which I am familiar in the wild. The stems, although initially growing upwards as expected, sprawl down to the become prostrate in their distal sections. The result is a growth-form similar to mallee but with much of the outer foliage trailing along the ground.

Why does E. erythrocorys differ from other multi-stemmed, wildfire-tolerant eucalypts in having this oddly recurved growth-form?

One possible reason is its tenuous relationship with fire in a type of vegetation which is not easily classified as either typical mallee (https://www.anbg.gov.au/photo/vegetation/mallee-woodlands-shrublands.html) or typical kwongan (https://en.wikipedia.org/wiki/Kwongan).

Most species of mallee are not only tolerant of wildfire, but intimately adapted to a regime of periodic combustion in which all their stems die by scorching, and growth resumes from ground level. Usually the vegetation is dense enough that the flames engulf all including the crowns of the mallees. However, eucalypts tend to exclude flammable shrubs from the patch directly under the crown, which means that, if the stand is sparse, there is a chance that the fire will fail to ignite the foliage of the upper storey, simply burning through the heathy understorey and leaving the eucalypts partly unburnt.

In the case of E. erythrocorys, the vegetation is indeed relatively sparse, partly because the surface is so stony. The heathy understorey looks barely dense enough to carry the flames across the empty patches under the mallees.

What E. erythrocorys seems to arrange, by having its outermost foliage trailing back down to the ground, is a ladder whereby the flames can climb up into the crown. This would ensure the desired combustion of the foliage, which as in other mallees rejuvenates the plant and self-fertilises it with its own ash.

The problem in cultivation is that no gardener or arborist, private or municipal, wants an untidy sprawl-mallee. So the natural shape of the plant is modified in the sapling. However, this cannot correct the leaning which is 'hardwired' in the remaining few boles. This inclination of the foliage towards the ground, now made dysfunctional, results sooner or later in partial collapse.

In summary, my finding is that the auto-amputation of the stem-system of E. erythrocorys is not a case of the sort of self-pruning so well-known in tree eucalypts. Instead it is a result of artificial distortion of the natural shape of the plant.

Horticulturally desirable though this species is, its natural adaptations are such that growing it as a tree is unlikely to be achieved without selective breeding.

Posted on October 14, 2021 10:25 PM by milewski milewski | 1 comment | Leave a comment

October 13, 2021

Bird-beak hakea epitomises plants dedicated to combustion

Bird-beak hakea (Hakea orthorrhyncha, http://anpsa.org.au/h-ort.html and https://en.wikipedia.org/wiki/Hakea_orthorrhyncha and https://florabase.dpaw.wa.gov.au/browse/profile/2192 and https://www.bgpa.wa.gov.au/about-us/conservation/plant-of-the-month/2001-july-2015) has the 'perfect resume' as an example of adaptation to an ecological syndrome which is seen at its most extreme in Western Australia.

It is one of those plants that 'says it all' in its combination of the various adaptive features of organisms to a particular regime in the natural environment.

Australia - and particularly Western Australia - has the poorest soils in the world: extensive deep sands exhausted of most nutrients by eons of weathering and leaching on a flat landscape.

On such soils, plants are not worth eating, which means that they tend to be consumed and recycled by combustion instead of digestion.

Plants well-suited to such environments, with their periodic wildfires, include multi-stemmed shrubs. They have foliage which is flammable even when green, and the means to regenerate new foliage rapidly from the ashes.

In the case of bird-beak hakea this means a woody burl just below ground-level, which survives even if all the stems of the plant are killed by the heat. This lignotuber (https://en.wikipedia.org/wiki/Lignotuber) produces new shoots without having to start again from seed.

And a crucial point to understand about plants is that - if appropriately adapted and living in sunny climates - they can make plenty of carbohydrate even on poor soils. This is partly because the enzymes of photosynthesis depend on metals, particularly magnesium and iron, which remain sufficient even where the core nutrients (particularly phosphorus and zinc) have become vanishingly scarce.

Carbohydrate is what sugar, plant fibre and wood are made of, depending on the degree of polymerisation. Because carbohydrate is the one product that nutrient-poor plants are affluent in, they use it in various ways to offset all the other disadvantages in their environments.

This is why bird-beak hakea has recruited birds to transport its pollen. Instead of settling for bees, it has the nectar to attract far larger, more energetic pollinators. Red is a hue invisible to bees but conspicuous to birds (https://apps.des.qld.gov.au/species-search/details/?id=1482#!lightbox-uid-0), and it signifies a font of sugar as well as hinting at the flames that propagate the plant in the longer term.

So bird-beak hakea is both 'pyrophilic' (loving fire) and 'ornithophilic' (loving honeyaters https://en.wikipedia.org/wiki/Honeyeater and other pollinating birds).

Bird-beak hakea uses its carbohydrates to fortify its leaves with lignin, making them stiff, spinescent and nearly as flammable as cardboard. And it also converts its roots into a dense, cardboard-like mat, protected from fire by being just below the sand (see https://en.wikipedia.org/wiki/Cluster_root). This mat absorbs, before they are lost, any nutrients that land in the form of dust and ash, thus providing the means for regrowth.

Furthermore, this species uses its carbohydrates in a remarkable way to protect its seeds. The seed-capsule is fortified into a lump of wood, 2 cm by 4 cm, which remains sealed and alive for years until the next fire arrives.

This makes bird-beak hakea both 'bradysporous' (storing the seed on the plant instead of in the ground, https://en.wikipedia.org/wiki/Bradyspory) and woody-fruited (protecting the seed from parrots and other seed-eating animals).

Various flammable plants on other continents show one or two of the above features, but none beyond Australia combines them all in one species. This is largely because nutrient-poverty is not as extensive and extreme, and wildfire does not replace herbivory as thoroughly, on other continents.

For example, in the Mediterranean Basin there are several types of shrub which possess lignotubers (https://www.researchgate.net/publication/229476710_Resprouting_of_the_Mediterranean-type_shrub_Erica_australis_with_modified_lignotuber_content and https://en.wikipedia.org/wiki/Erica_Australis and https://jgpausas.blogs.uv.es/?s=Phillyrea). Others have evergreen, spinescent leaves (https://en.wikipedia.org/wiki/Juniper). But none of these plants is ornithophilous or bradysporous, and all lack cluster roots.

In South Africa there are proteas, belonging to the same family as bird-beak hakea, that have lignotubers, cluster roots, bird-pollinated flowers, and even bradyspory (e.g. https://en.wikipedia.org/wiki/Protea_cynaroides). But they lack leaf-spinescence and woody fruits.

In North America there are 'closed-cone pines (see https://en.wikipedia.org/wiki/Pinus_serotina and https://en.wikipedia.org/wiki/Pinus_contorta) with what amount to woody fruits. However, these lack all the other features of the syndrome, including a shrubby growth-form.

Plants such as bird-beak hakea (http://www.northqueenslandplants.com/Australian%20Plant%20Families%20N-S/Proteaceae/Hakea/Hakea%20orthorrhyncha%20.html and https://domusnursery.com.au/plants/plant.cshtml?plant_code=hakort and https://www.australianseed.com/shop/item/hakea-orthorrhyncha and https://mucheatreefarm.com.au/product/hakea-orthorrhyncha/ and https://davesgarden.com/guides/pf/showimage/413766/#b and https://triggplants.com.au/product/hakea-orthorrhyncha-in-50mm-forestry-tube/ and http://www.consultaplantas.com/index.php/en/plants-from-d-to-l/2218-hakea-orthorrhyncha-or-bird-beak-hakea-care-and-growing) nowhere dominate the vegetation, even on the coastal sandplains of southwestern Australia (https://www.alamy.com/biodiversity-of-flora-in-heath-kwongan-habitat-wheatbelt-frank-hann-national-park-november-2013-image342310831.html).

But the fact that any such species exists is testimony to the ecological peculiarity of Australia among the continents. In its own way, bird-beak hakea is as odd, by global standards, as the kangaroos which exert a minimal effect in its habitat (https://www.rswa.org.au/publications/Journal/80(2)/80(2)wann.pdf).

Posted on October 13, 2021 08:36 PM by milewski milewski | 4 comments | Leave a comment

October 10, 2021

Diet of the feral camel in Australia, part 2

The most recent wild ancestor of the dromedary (Camelus dromedarius) lived in what is now Dubai (https://www.pnas.org/content/113/24/6707 and https://www.pnas.org/content/pnas/suppl/2016/05/04/1519508113.DCSupplemental/pnas.1519508113.sapp.pdf) on a remote coastal plain which is hard to relate to the directions of the compass but forms a 'horn' of the Arabian subcontinent in the same way that the Horn of Africa relates to the African continent.

Given this origin, it might be informative to refer the favourite food-plants of the dromedary, in its feral state, in Australia to the flora of Arabia. In particular, which of the genera preferred in Australia are also indigenous to Arabia, albeit as different species?

A principle to bear in mind is that, in general, the leaves and shoots of stem-spinescent or hedge-forming plants are more palatable and nutritious than those of plants lacking these structural defences. Leaf-spinescent plants (other than thistles, https://www.farmonline.com.au/story/4243900/scotch-thistles-secret-enemy/#:~:text=%E2%80%9CThey%20love%20Scotch%20thistle%20in,and%20camels%20are%20the%20answer. and https://www.armstrongorganics.com/camels) tend to follow the opposite trend. Their foliage tends to be nutrient-poor, epitomised by the distinctively Australian hummock grasses (Triodia, see https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-185X.2007.00017.x).

In comparing Australia with Arabia, we can start with the amaranths and other halophytes (https://en.wikipedia.org/wiki/Halophyte).

Atriplex, a cosmopolitan genus of sodic-adapted shrubs and herbaceous plants, is locally conspicuous in semi-arid Australia (https://www.daf.qld.gov.au/business-priorities/agriculture/plants/crops-pastures/pastures/saltbush#:~:text=Saltbushes%20are%20members%20of%20a,staple%20diet%20of%20many%20animals.), and inconspicuous in Arabia (https://www.cabi.org/ISC/abstract/20013152218).

Wherever it occurs, Atriplex is a fairly nutritious plant for herbivores (http://researchhub.buan.ac.bw/bitstream/handle/123456789/284/10.1.1.585.8784.pdf?sequence=1 and https://www.tandfonline.com/doi/abs/10.2989/10220110309485822). However, its food-value tends to be limited because its concentraction of sodium is not necessarily matched by other useful elements.

Probably more important in the diet of the dromedary in Arabia is the related genus Caroxylon, which does not occur in Australia and is associated with nutrient-rich soils rather than merely sodic ones. The branching stems and diminutive leaves (e.g. see https://en.wikipedia.org/wiki/Salsola_vermiculata and https://en.wikipedia.org/wiki/Salsola_imbricata) provide antiherbivore defences lacking in Atriplex and most of the other amaranths in Australia. This suggests that Caroxylon is more palatable than Atriplex to the dromedary.

One way to view the various halophytic amaranths (Atriplex, Chenopodium, Enchylaena, Maireana, Sclerolaena, Tecticornia) eaten by the feral dromedary in Australia is as nutrient-poor counterparts - which were relatively exempt from herbivory in Australia before the arrival of domestic livestock - to Caroxylon.

The amaranth Ptilotus (https://en.wikipedia.org/wiki/Ptilotus) is non-halophytic but conforms to this pattern in being common but not nutritious enough to be under pressure from herbivores. This is true notwithstanding the phosphorus-richness of certain species of Ptilotus (https://www.publish.csiro.au/bt/BT19188).

Zygophyllaceae are unrelated to amaranths phylogenetically, but show a similar relationship to sodicity and herbivory. Although Zygophyllum occurs in Arabia and in Australia, the closely related genus Tetraena - absent from Australia - has a growth-form convergent with Caroxylon in its adaptation for intense herbivory (https://en.wikipedia.org/wiki/Tetraena_alba and https://en.wikipedia.org/wiki/Tetraena_qatarensis).

The zygophylls also contain Tribulus, which is not halophytic. This is a favourite food of the dromedary (https://arkbiodiv.com/2019/05/05/camels-flower-%D8%B2%D9%87%D8%B1-tribulus-is-the-precious-flora-of-the-arabian-desert/) and indigenous to both Australia and Arabia, although the commonest species has probably been introduced anthropogenically (https://en.wikipedia.org/wiki/Tribulus).

Portulaca is yet another genus indigenous to both Australia and Arabia, and likely to be a favourite food-plant of the dromedary in both regions.

Acacias occur in both Australia and Arabia, but in the form of different genera. Whereas the species eaten by the feral dromedary in Australia belong to the genus Acacia and have phyllodes instead of leaves, those likely to have been eaten in Arabia belong to the genus Vachellia, have bipinnately compound leaves, and are extremely spinescent (https://en.wikipedia.org/wiki/Vachellia_tortilis and https://en.wikipedia.org/wiki/Vachellia_flava).

Carissa and Capparis nowhere dominate the vegetation, but exemplify preferred species shared between Australia and Arabia. Not only is the dromedary likely to eat these plants (which are variably spinescent depending on pressure from herbivory) in both regions, but the same species is indigenous in both cases (https://en.wikipedia.org/wiki/Carissa_spinarum and https://en.wikipedia.org/wiki/Caper).

The feral dromedary in Australia coexists in places with kangaroos. However, there is little competition for food, for several reasons.

Firstly, all species of kangaroos prefer grasses, which are generally not preferred by the feral dromedary. Secondly, kangaroos do not generally eat acacias, eucalypts or eremophilas. Thirdly, the dromedary can reach twice - and perhaps threefold (https://www.naturepl.com/stock-photo-bactrian-camel-camelus-bactrianus--three-beneath-tree-one-standing-on-nature-image01643198.html) - as high as kangaroos can. And fourthly, much of the range of the feral dromedary is in the Australian Empty Quarter, where all kangaroos were scarce at the time of European arrival and remain scarce today.

It is noteworthy that the feral camel accepts eucalypts and proteas to a greater extent than hummock grasses.

I can summarise as follows.

Although the vegetation differs greatly between semi-arid Australia and Arabia, the dromedary is mobile and versatile enough to find equivalent, and in many cases closely related, plants to eat in both regions. Among comparable genera of favourite food plants, Australian species tend to be less spinescent or hedged than Arabian species, which may allow the dromedary to forage more efficiently - but not necessarily more sustainably - in its adopted than in its original habitat.

Posted on October 10, 2021 10:44 PM by milewski milewski | 9 comments | Leave a comment

Diet of the feral camel in Australia, part 1

Camelus dromedarius (https://en.wikipedia.org/wiki/Dromedary) is unusual among the feral animals in Australia.

Firstly, among all the domestic species of mammals, the dromedary is least closely associated with any known wild ancestor - despite domestication having occurred as recently as four thousand years ago.

Secondly, this is the only feral ungulate successful in the extensive nutrient-desert that I have called the Australian Empty Quarter (see my last Post and https://www.researchgate.net/figure/Map-of-project-study-area-showing-the-camel-distribution-boundary-major-desert-features_fig1_255687533).

Thirdly, the dromedary has such slow metabolism, growth and reproduction, relative to most other artiodactyls, that it seems somewhat convergent with extinct large marsupials (e.g. https://en.wikipedia.org/wiki/Palorchestes) of the Pleistocene in Australia (none of which is known to have occurred in the Australian Empty Quarter).

Given how odd the dromedary is for a domestic herbivore - resembling a wild animal 'pre-adapted' for the Australian semi-arid zone - its diet in its adopted habitat (https://dpir.nt.gov.au/__data/assets/pdf_file/0004/233455/tn116.pdf and https://www.dreamstime.com/stock-photo-australian-camels-outback-pair-wild-dromedary-graze-image34710910 and https://www.alamy.com/dromedary-camels-two-grazing-camelus-dromedarius-feral-animals-living-wild-introduced-to-australia-now-widespread-in-wild-image181672328.html) is of obvious interest.

What can we say about the ecological nature of those genera and species of plants most preferred by the dromedary in its feral state in Australia?

The overall finding is hardly surprising. The preferred plants tend to belong to:

  • cosmopolitan genera and weedy species
  • nutritional categories which boost palatability (e.g. nutrient-parasitism and symbiotic nitrogen-fixation)
  • genera and species restricted to the patches of relatively nutrient-rich soils (by Australian standards), and
  • regeneration after wildfires.

The plant species preferred by the dromedary in Australia are generally not the dominant/commonest ones, and this is particularly so in the Australian Empty Quarter. Instead, they tend to belong to families such as the Amaranthaceae, possessing soft foliage and growing on the least acidic soils or as temporary flushes dependent on ash.

Favourite food-plants of the feral dromedary, in the category of symbiotic nitrogen-fixers, belong to the Mimosaceae and Fabaceae.

In the former family are Acacia oswaldii (https://en.wikipedia.org/wiki/Acacia_oswaldii and http://worldwidewattle.com/speciesgallery/oswaldii.php) and several other species in the same genus, some of which are spinescent (http://worldwidewattle.com/speciesgallery/descriptions/pilbara/html/victoriae.htm and http://worldwidewattle.com/speciesgallery/descriptions/pilbara/html/tetragonophylla.htm)

In the latter family are Erythrina (https://en.wikipedia.org/wiki/Erythrina_vespertilio), Crotalaria, Indigofera, Rhynchosia, and Swainsona (https://en.wikipedia.org/wiki/Swainsona)

Favourite food-plants in the category of parasites (including both mistletoes and free-standing shrubs which parasitise the roots of other plants) are Amyema, Anthobolus, Cassytha, Cuscuta, Lysiana (https://en.wikipedia.org/wiki/Lysiana_exocarpi) and Santalum spp. (https://en.wikipedia.org/wiki/Santalum).

Other favourite food-plants tend to belong to genera occurring naturally on several continents, some of which can be called cosmopolitan.

These are (in alphabetical order):

Atriplex
Boerhavia
Calandrinia
Capparis
Carissa
Chenopodium
Cleome
Glycine
Ipomoea
Jasminum
Kali (https://en.wikipedia.org/wiki/Kali_(plant))
Lepidium
Marsdenia
Pittosporum
Pterocaulon
Portulaca
Psydrax
Senecio
Sida
Tribulus
Trichodesma
Tripogon
Ventilago
Zygophyllum

The following genera are restricted to Australia but associated with sodic soils: Enchylaena, Lawrencia, Maireana, Sclerolaena and Tecticornia.

This brings us to what are perhaps the most interesting of the favourite food-plants, i.e. those belonging to typically Australian families/genera.

These are (in no particular order) as follows:

Eucalyptus gammophylla (https://en.wikipedia.org/wiki/Eucalyptus_gamophylla)
Grevillea juncifolia (https://en.wikipedia.org/wiki/Grevillea_juncifolia) and G. eriostachya (https://en.wikipedia.org/wiki/Grevillea_eriostachya)
Codonocarpus cotinifolius (https://en.wikipedia.org/wiki/Codonocarpus_cotinifolius)
Eremophila longifolia (https://en.wikipedia.org/wiki/Eremophila_longifolia and http://anpsa.org.au/APOL15/sep99-2.html)
Brachychiton gregorii (https://en.wikipedia.org/wiki/Brachychiton_gregorii)
Lechenaultia divaricata (https://en.wikipedia.org/wiki/Lechenaultia)
Ptilotus spp. (https://en.wikipedia.org/wiki/Ptilotus_macrocephalus and https://en.wikipedia.org/wiki/Ptilotus_polystachyus)
Calotis hispidula (https://en.wikipedia.org/wiki/Calotis_hispidula)
Rhodanthe floribunda (https://en.wikipedia.org/wiki/Rhodanthe_floribunda)
Scaevola parvifolia (https://en.wikipedia.org/wiki/Scaevola_parvifolia)
Stylobasium spathulatum (https://en.wikipedia.org/wiki/Stylobasium_spathulatum).

Atalaya hemiglauca (https://en.wikipedia.org/wiki/Atalaya_hemiglauca) belongs to a mainly Australian genus with one species in southern Africa.

What does the vegetation look like when/where the favourite food-plants of the feral dromedary are so common that they dominate the scene? Here are some glimpses.

Regeneration after wildfire: https://keys.lucidcentral.org/keys/v3/scotia/key/Plants%20and%20Fungi%20of%20south%20western%20NSW/Media/Html/Codonocarpus_cotinifolius.htm

Prominence of phyllodinous acacias: https://www.malleeconservation.com.au/blog/acacia-oswaldii

Prominence of 'saltbush' and other amaranths adapted to sodic soils: https://www.nationalparks.nsw.gov.au/plants-and-animals/saltbush.

to be continued...

Posted on October 10, 2021 08:45 AM by milewski milewski | 2 comments | Leave a comment

October 09, 2021

The Australian Empty Quarter: epitome of a nutrient-desert

Everyone knows that Australia is the driest continent. However, how many know that 'desert' in Australia refers less to a lack of water than to a lack of nutrients?

On most maps of land use in Australia, a large-scale pattern is obvious but does not seem to have been pointed out as such. This is a broad vertical band across the western half of the continent, centred just west of the border between Western Australia (https://en.wikipedia.org/wiki/Western_Australia#/media/File:Western_Australia_in_Australia.svg) and South Australia/Northern Territory. The climate varies from tropical in the north to temperate in the south.

In this broad band there is, to this day, negligible farming or other utilisation of the land (see https://www.agriculture.gov.au/abares/aclump and https://www.veganaustralia.org.au/impact_of_a_vegan_agricultural_system_on_land_use and https://www.researchgate.net/figure/A-2000-01-national-scale-land-use-map-illustrating-the-broad-distribution-of-pastures_fig1_230817486 and https://www.moffittsfarm.com.au/2014/01/04/land-use-australia-2005-2006-source-abares/ and https://ars.els-cdn.com/content/image/1-s2.0-S0959378016300231-gr1.jpg and https://www.researchgate.net/figure/Sample-locations-and-land-use-types-in-Australia-The-agricultural-areas-of-Australia-are_fig1_288059143 and https://www.researchgate.net/figure/a-Carnahan-classification-of-current-vegetation-for-Australia-AUSLIG-1990-and-b_fig1_236770005 and https://www.creativespirits.info/aboriginalculture/land/aboriginal-homelands-outstations).

This feature needs a name, and I suggest we call it the Australian Empty Quarter.

What is most surprising about the Australian Empty Quarter is how densely-vegetated it is with evergreen perennial plants (https://diamantina-tour.rezdy.com/95387/great-victoria-desert-nullarbor-expedition?lang=ja and https://www.worldatlas.com/articles/where-does-the-great-victoria-desert-lie.html and https://www.abc.net.au/science/photos/2012/11/21/3636626.htm?xml=3636626.mediarss.xml#bigpicturepos and https://www.istockphoto.com/photo/marble-gum-gm532574825-55893698 and https://upload.wikimedia.org/wikipedia/commons/8/81/Eucalyptus_gongylocarpa.jpg and https://www.exploroz.com/wildflowers/395+marble-gum and https://www.alamy.com/stock-photo-camel-crossing-the-great-victoria-desert-western-australia-97792062.html).

The driest part of Australia, which has sparse vegetation, occurs far to the east and is a different geographical feature (http://www.truganinaweather.com/weather-education/australian-climate-maps.htm and https://en.wikipedia.org/wiki/Lake_Eyre_basin).

The Australian Empty Quarter, despite looking far more luxuriant than the conventional image of desert, is even poorer in large animals than the rest of the continent. The emu (Dromaius novaehollandiae, https://upload.wikimedia.org/wikipedia/commons/f/ff/Emu_distribution.png and https://upload.wikimedia.org/wikipedia/commons/8/8b/Dromaius_novaehollandiae_map_distribution_2.svg) and kangaroos (mainly Osphranter rufus, http://www.ecoclimax.com/2017/05/kangaroo-distribution-in-australia-vs.html and https://www.echidnawalkabout.com.au/macropods-kangaroos-of-australia/ and https://bio1152.nicerweb.com/Locked/media/ch52/kangaroo.html) are largely absent.

Various other species of animals show a similar gap in their distributions (https://www.researchgate.net/figure/Magpie-plumage-variants-and-their-distribution-across-the-Australian-continent_fig1_232248336 and https://edition.cnn.com/2019/09/15/australia/australia-magpie-death-intl-hnk-scli/index.html).

The most significant plants in the Australian Empty Quarter are hummock grasses belonging to the genus Triodia (https://en.wikipedia.org/wiki/Triodia_(plant)). These are adapted to nutrient-poverty and fire to the degree that they have minimal value for herbivores (https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-185X.2007.00017.x). Their leaves are woody, resinous and unpalatable.

The ultimate environmental reason for the Australian Empty Quarter is a combination of extreme flatness and underlying bedrock of nutrient-poor sediments such as sandstone. This land has been geologically stable since the time of dinosaurs, so that the soils, sandy and poor to start with, have become profoundly depleted of phosphorus and zinc in particular.

This limits herbivory so much that vegetation is left to grow until wildfire returns, and combustion has replaced digestion as the most important recycler of nutrients.

The Australian Empty Quarter is best understood as a nutrient-desert rather than a rainfall-desert because, even if it were well-watered, it would remain largely devoid of large animals. Although this zone is semi-arid, it is ecologically aligned with the African Empty Quarter (see my Post of July 18, 2021) rather than the conventional concept of a desert.

As an example of a nutrient-desert, the Australian Empty Quarter is far more extreme than the Kalahari-derived sand-sheet, covered with miombo woodland (https://en.wikipedia.org/wiki/Miombo), in Angola - in which the incidence of large animals is minimal by African standards but categorically greater than in any part of Australia.

One of the principles illustrated is this:

There are some climates just too dry for the vegetation to maintain cover over the land, and this is the conventional concept of desert. However, no soils on this Earth are so nutrient-poor that woody plants cannot grow on them, albeit slowly. Thus arises the combination we see in the Australian Empty Quarter: a vegetated plain effectively useless to man and beast.

Except, that is, for a camel...

Posted on October 09, 2021 06:08 AM by milewski milewski | 4 comments | Leave a comment

October 08, 2021

The bambis, part 7: why do certain genera show tropical hues?

Tropical organisms often seem more colourful than organisms from the non-tropical latitudes (https://tomwhite.io/docs/dalrymple_et_al_2015_life_isnt_more_colourful_in_tropics.pdf). Think of coral reefs and Amazonian parrots.

We would not expect this trend to apply to ungulates, because neither the hoofed mammals nor the carnivores which hunt them can see hues such as red and green. For these animals, even browns may be effectively just shades of grey.

In the visual systems of ungulates and carnivores, the main sensitivity is to movement, not colour. And hues would be indiscernible at night anyway - even to the most light-sensitive eyes of nocturnal animals.

So it is puzzling that two types of small antelopes in Africa seem more colourful in the tropical than in the non-tropical parts of their ranges, and that the patterns are convergent.

Bush duikers (Sylvicapra, https://wildlifesafari.info/duiker_common.htm) and klipspringers (Oreotragus, https://www.mindenpictures.com/stock-photo-klipspringer-oreotragus-oreotragus-adult-male-standing-on-rock-naturephotography-image80072538.html) are not particularly closely related to each other, but both range widely across sub-Saharan Africa. In both cases the fur is uniformly brownish at high latitudes in southern Africa, but differentiated into yellowish/reddish hues vs greyish in the tropics.

And in both cases the richer hues occur on the forequarters, whereas the greyish occurs on the hindquarters.

Sylvicapra

https://www.mindenpictures.com/stock-photo-common-duiker-sylvicapra-grimmia-standing-south-africa-naturephotography-image80010109.html

https://eol.org/media/6672123

https://www.inaturalist.org/observations/95528820

https://www.inaturalist.org/observations/17353514

https://www.inaturalist.org/observations/86593063

Oreotragus

https://www.alamy.com/klipspringer-antelope-oreotragus-oreotragus-manyara-national-park-tanzania-africa-image342083213.html

https://www.alamy.com/klipspringer-oreotragus-oreotragus-adult-standing-on-rock-hells-gate-park-in-kenya-image341506471.html

https://www.alamy.com/a-female-klipspringer-oreotragus-oreotragus-in-the-savuti-region-of-botswana-africa-image331190410.html

https://www.alamy.com/klipspringer-oreotragus-oreotragus-adult-standing-on-rocks-hells-gate-park-in-kenya-image343726089.html

https://www.alamy.com/klipspringer-oreotragus-oreotragus-male-on-territorial-rock-serengeti-image64055813.html

https://www.alamy.com/klipspringer-oreotragus-oreotragus-on-the-rocky-outcrops-in-the-lobo-image5458070.html

https://www.alamy.com/stock-photo-klipspringer-on-rock-serengeti-tanzania-africa-103618837.html

Not only have Sylvicapra and Oreotragus converged with each other in this differentiation, but both have converged somewhat with a third, unrelated genus, namely Madoqua, which is restricted to the tropics.

Madoqua

https://upload.wikimedia.org/wikipedia/commons/7/75/Damara_Dik-Dik.JPG

https://www.agefotostock.com/age/en/details-photo/dik-dik-dikdik-rhynchotragus-kirki-tarangire-national-park-tanzania/MEV-10886650

https://www.agefotostock.com/age/en/details-photo/kirk-s-dik-dik-madoqua-kirki-serengeti-national-park-tanzania/YP6-1610372

https://www.gettyimages.ie/detail/photo/male-dik-dik-in-the-bush-royalty-free-image/505590060?adppopup=true

https://www.gettyimages.ie/detail/photo/kirks-dik-dik-madoqua-kirkii-tarangire-tanzania-royalty-free-image/562941793?adppopup=true

https://www.gettyimages.ie/detail/photo/dik-dik-lake-manyara-national-park-tanzania-africa-royalty-free-image/986199682?adppopup=true

The hues seen in these antelopes are dull compared with other tropical organisms, but raise a puzzle nonetheless.

In all three genera, the overall colouration is adaptively inconspicuous, allowing the figures to blend into their environments.

In which ways does differentiation of reddish at the anterior of the figure vs greyish at the posterior of the figure help to disguise small antelopes - particularly in the bright light of the tropics?

One possibility is that certain birds - which see all the hues - are important predators for bambis.

I refer in particular to the martial eagle (Polemaetus bellicosus, https://en.wikipedia.org/wiki/Martial_eagle#Mammals).

See https://www.youtube.com/watch?v=ZwS-yGOc8UY and https://www.reddit.com/r/HardcoreNature/comments/hdl261/juvenile_martial_eagle_feeding_on_a_klipspringer/ and http://wildernessdiary.squarespace.com/eagles-kenya/martial-eagle-on-dik-dik-kill-09-10-october-2007/908168 and https://i.redd.it/d9sjsm1mtyw41.jpg and https://i.redd.it/ahfpga61lf851.jpg and https://africageographic.com/martial-eagle-with-impala-kill-2/ and https://www.flickr.com/photos/david_o/4036136915 and https://i.redd.it/975n8t4uqy141.jpg and https://www.youtube.com/watch?v=c1Mzko2wUuU and https://www.eveshamphoto.net/photo2017/authors/veronica_rice.htm and https://www.alamy.com/stock-photo-martial-eagle-polemaetus-bellicosus-with-killed-young-of-a-thomsons-59310018.html and https://www.kruger-2-kalahari.com/martial-eagle-takes-bushbuck.html and https://www.mediastorehouse.com/ardea-wildlife-pets-environment/dec2014/2/martial-eagle-impala-kill-10493024.html#openModal and https://www.classicafrica.com/News/newsView.asp?NewsId=40968592&CategoryID=49).

Posted on October 08, 2021 10:12 AM by milewski milewski | 1 comment | Leave a comment

October 05, 2021

The bambis, part 6: a selection of the most revealing photos of klipspringers

For many large mammals, the photographic record is just sufficient to give an idea of what the species looks like. However, some species - such as klipspringers - are so attractive and photogenic that there are now enough photos to reveal subtleties and details.

I have scoured the Web, looking for photos that happen to reveal more than the photographers focussed on. In no particular order, here are my current choices for little-known aspects of klipspringers.

GAITS:

Everyone knows that klipspringers are the ungulates most specialised for rocky terrain, but how many realise that their walking gait (even on flat ground) is correspondingly extreme? And that they can climb trees?

Whereas antilopins - like most ruminants of open vegetation - amble, klipspringers follow a different sequence of movements of the limbs. Klipspringers are both the most extreme cross-walkers among ruminants and the only 'hyper-unguligrade' mammals on Earth. Like most ungulates, they walk on their claws, but unlike all other ungulates they walk on the tips of their claws (https://www.mindenpictures.com/stock-photo/klipspringer-(oreotragus-oreotragus)-adult-close-up-of-front-hoof/search/detail-0_80155912.html).

Compare the steenbok (Raphicerus campestris, https://www.alamy.com/stock-photo-male-steenbok-in-kruger-national-park-south-africa-34310778.html) and Kirk's dikdik (Madoqua kirki, https://www.alamy.com/male-dik-dik-antelope-walking-carefully-through-the-steppe-namibia-africa-image330805151.html) with the following of klipspringers: https://www.alamy.com/male-klipspringer-oreotragus-oreotragus-a-dry-country-antelope-with-thick-coat-walking-on-tip-toe-on-rocky-lava-in-tsavo-west-np-kenyaafrica-image241664074.html and https://www.alamy.com/a-klipspringer-ewe-oreotragus-oreotragus-walking-between-rocks-image262965521.html and https://www.inaturalist.org/observations/53953068 and https://www.alamy.com/klippspringer-running-lateral-oreotragus-oreotragus-image6351701.html and https://www.alamy.com/male-klipspringer-oreotragus-oreotragus-a-dry-country-antelope-with-thick-coat-walking-on-tip-toe-on-rocky-lava-in-tsavo-west-np-kenyaafrica-image241664075.html.

If you find yourself cross-eyed at the positions of the walking limbs, try again with the mountain gazelle (Gazella gazella), which - like the bambis above but unlike klipspringers - ambles: https://www.dreamstime.com/stock-photo-mountain-gazelle-walking-field-israel-image91922790.

The order in which klipspringers move their limbs is awkward in the sense that the hind foot risks bumping against the fore foot. However, what these rupicolous antelopes are specialised for is a combination of 'tiptoe' and stability. Cross-walking is the most stable of walking gaits, helping to explain why monkeys and the koala, adapted to walk along the limbs of in trees, cross-walk even on flat ground...

...which brings us to klipspringers in trees: https://m.facebook.com/findingalegend/photos/a.1415644325204508/3289678784467710/?type=3&source=57 and https://bcgforums.com/index.php?threads/tree-jumpers-klipspringer.1724/#lg=attachment3600&slide=0 and https://www.picuki.com/media/2625704040363578267 and https://www.picuki.com/media/2595913754140872450 and .

SERENGETI:

Everyone knows that the migrations of large ungulates in the Serengeti attract the world's best photographers of wildlife. However, how many realise that the local subspecies (schillingsi) of klipspringer has been excellently portrayed as a result?

https://www.alamy.com/klipspringer-oreotragus-oreotragus-antelope-serengeti-national-park-tanzania-africa-image359928995.html and
https://www.alamy.com/a-male-klipspringer-oreotragus-oreotragus-in-a-typical-pose-on-a-rocky-outcrop-a-kopje-klipspringers-have-evolved-to-walk-on-the-tips-of-their-ho-image333900161.html and https://www.alamy.com/klipspringer-antelope-oreotragus-oreotragus-looking-at-camera-serengeti-national-park-tanzania-africa-image359928767.html.

SEXUAL DIMORPHISM:

The following seems to illustrate the fact that some females, as well as all males, grow horns in subspecies schillingsi of the Serengeti: https://www.alamy.com/klipspringer-oreotragus-oreotragus-antelopes-serengeti-national-park-tanzania-africa-image359928965.html

AURICULAR FLAG:

The auricular flag in klipspringers is precocial (https://www.picuki.com/media/2620738757646356923). The conspicuous pattern is already present in juveniles, and the ear pinnae are already fully grown when the horns are still short: https://www.alamy.com/stock-photo-klipspringer-oreotragus-oreotragus-serengeti-national-park-tanzania-31370503.html and https://www.alamy.com/stock-photo-kenya-maralal-parkati-a-rare-sight-of-three-klipspringers-oreotragus-19159611.html.

In the Cape klipspringer, the ear pinnae are similarly precocial in size, but there is no auricular flag in either adults or juveniles: https://www.alamy.com/klipspringer-oreotragus-oreotragus-pair-montagu-pass-western-cape-south-africa-image208844037.html. This would be one of the main reasons to reclassify the Cape klipspringer as a separate species, not just a subspecies.

QUASI-OXPECKERS:

Everyone knows that klipspringers are more-or-less monogamous, and some may know that they 'kiss' with their preorbital glands. But how many realise that the married partners do not groom each other?

Instead, klipspringers have an odd relationship with starlings (belonging to the same family as oxpeckers), which remove ticks from the head: https://www.sciencephoto.com/media/473119/view/klipspringer-with-crows and https://www.picuki.com/media/2579277603076704030 and https://www.alamy.com/red-winged-starling-onychognathus-morio-on-klipspringer-oreotragus-image151850989.html and https://wildanimalworlds.files.wordpress.com/2013/09/klipspringer-oreotragus-oreotragus.jpg and https://www.nmbt.co.za/listing/augrabies_falls_national_park.html#lightbox[Augrabies%20Falls%20National%20Park]/2/.

Animals as small-bodied as klipspringers are not attractive to oxpeckers, and it is surprising that klipspringers are attractive to Onychognathus spp. (https://en.wikipedia.org/wiki/Onychognathus). Perhaps this reflects the peculiar nature of the fur (see below) in some way (https://www.researchgate.net/publication/230128769_Grooming_rates_in_klipspringer_and_steinbok_reflect_environmental_exposure_to_ticks).

Even a bird as different from oxpeckers as the familiar chat (https://en.wikipedia.org/wiki/Familiar_chat) participates in the de-ticking of klipspringers: https://www.gettyimages.com.au/detail/photo/oreotragus-oreotragus-familiar-chat-catching-flies-royalty-free-image/90049548?adppopup=true.

TAIL:

Everyone knows that the tail is hardly noticeable in klipspringers, but how many realise that it is proportionately longer than in most ruminants adapted to the cold parts of the Northern Hemisphere (e.g. chamois, ibex, wild sheep, moose, wapiti, caribou, roe deer, pronghorn)?

In klipspringers, the tail is not rudimentary, it just lacks a tassel (https://www.dreamstime.com/sturdy-male-female-klipspringer-pair-standing-tiptoe-rock-mapungubwe-south-africa-image187197351). And its colouration is inconspicuous - which is consistent with a shift of function from the caudal flagging so common among ruminants to the auricular flagging seen in the saltatrixoides-group of Oreotragus.

PECULIAR FUR:

Everyone knows that the fur of klipspringers is oddly stiff and brittle, but how many realise that the colour of the hairs is restricted to the tips?

The following individual of subspecies schillingsi, in the Serengeti, was photographed consecutively as it walked among plant stems too flimsy to be visible but stiff enough to ruffle the fur in passing: https://www.alamy.com/klipspringer-oreotragus-oreotragus-on-the-rocky-outcrops-in-the-lobo-image5458080.html and https://www.alamy.com/klipspringer-oreotragus-oreotragus-on-the-rocky-outcrops-in-the-lobo-image5458079.html.

When klipspringers have had a 'close shave' with a predator, and the brittle fur has been partly sheared in the scramble to escape, this is how it looks: https://www.picuki.com/media/2626904329229554593 and https://www.picuki.com/media/2594699343506065312.

SUCKLING POSTURE OF JUVENILES:

In antilopin bovids of similar body size to klipspringers, such as the steenbok (https://www.shutterstock.com/nb/video/clip-18770927-steenbok-antelope-raphicerus-campestris-suckling-lamb-south) and oribis (https://www.alamy.com/stock-photo-female-oribi-ourebia-ourebi-with-nursing-calf-54880619.html), the juvenile suckles by splaying the fore legs. By contrast, in klipspringers a kneeling position seems to be adopted: https://www.alamy.com/stock-photo-klipspringer-in-the-tsavo-west-national-park-kenya-33777800.html.

Posted on October 05, 2021 12:28 AM by milewski milewski | 10 comments | Leave a comment