Caprines: The World's Largest Goats

Takin (Sichuan subspecies)

All of the various kinds of caprine that I have described so far in this series have looked, more or less, either goat-like or sheep-like. There are just two species left, and those form something of an exception. While most caprines are fairly medium-sized as hoofed animals go, these are much larger, more muscular, animals.

It used to be thought, on this basis, that they were closely related to one another, representing an early branch in the evolution of goat-like animals that split away from their relatives well before the appearance of actual goats or sheep. From modern genetic evidence, that no longer looks the case. They are, as we suspected, caprines, (although, despite the title of this post, not literally goats) but within that group, they are not particular closely related to one another. Instead, their apparent similarities are a coincidence, a case of parallel evolution where two animals, both fairly goat-like to start with, faced selective pressures to become larger.

The first of these animals is the takin (Budorcas taxicolor). Takins are very distinctive animals, quite hard to mistake for anything else, once you get a good look at them. The most obvious point, as I've already implied, is the size. A fully grown male takin stands over four feet high at the shoulder, and weighs upwards of 300 kg (660 lbs). The females are noticeably smaller, but still larger than even the males of any other caprine species (with, of course, one exception that I'll get to in a moment).

Island of the Giant Hedgehogs

Hoplitomeryx matthei

A well-documented phenomenon in evolution is that of insular dwarfism. What happens is that a population of large, usually herbivorous, animals become trapped by rising sea levels, finding themselves on an island where previously they had been able to roam free across a much wider region. In response, over the course of many, many generations, their descendants become smaller.

There are two main reasons why this happens. Firstly, there isn't so much food to eat on an island, so smaller animals that eat less will be at an advantage, and able to have more offspring that survive to have offspring of their own. But, while the problem of a limited food supply is more obvious on a smallish island, even on a large continent, the supply is never likely to be inexhaustible. In which case, why do large animals exist in the first place?

That, of course, is where the second reason comes in: predators. Being large is a protection against being eaten; lions and tigers, for instance, rarely eat elephants, rhinos, or hippos. Large predators, being at the precarious pinnacle of the food chain, and present in smaller numbers to start with, find it even harder to survive on small islands than herbivores, and they often simply die out. That removes the need for herbivores to avoid them: there's no real need to be too large for a lion to eat if the biggest thing you'll ever face is a fox, anyway.

That Funky Gibbon Song

A male agile gibbon

We humans learn to speak from our parents, with our mothers playing a particularly important role. It's because of this that we have different languages across the globe, rather than all speaking the same genetically-determined tongue, pre-programmed from birth. Yet, in other animals, communication seems to be primarily genetic, with social learning playing little, if any, role.

There are, of course, exceptions to this. We know, for example, that songbirds raised in isolation produce much simpler songs than those in a natural environment, able to hear, and respond to, other birds of their species. On the other hand, they do still sing, and the songs are much closer to normal ones than a similarly deprived human would be able to do with respect to English, French, or Gujarati.

Well, we're not songbirds, but we are mammals, and more specifically, anthropoid primates. Is there really such an absolute split between us and our close relatives? The calls of many primates can be quite complex, and this surely has something to do with why language became so important to us. Are these calls entirely genetically programmed, or are they, in some way, learned?

Welcome, the Olinguito

If you follow any sort of science news site, especially if you read the zoology bits, you cannot have failed to notice the recent announcement of the discovery of a "new species of carnivore" in South America. By the standards of such things, its a major news story - the last time this happened in the New World was in 1978, when the Colombian weasel was discovered. In addition to the news coverage, the original announcement is available to read (all 83 pages of it), free online, for anyone who cares to. There's probably not a lot I can add to all that.

Still, I feel that it's not something I should really ignore, so here's my take on it, and an attempt to put the discovery into some sort of context.

Let's start with the obvious: what is this new animal, exactly? The olinguito (Bassaricyon neblina) is a newly described species of olingo. Which may, in many people's minds, raise the question: "um... what's an olingo?"

Olingos are long-tailed, tree-dwelling, members of the raccoon family, found in the jungles of Central and South America. They were first scientifically described, as a group, by the American zoologist J.A. Allen in 1876, which is itself remarkably late (all the other main groups within the family had been discovered by 1830, and most of them well before that). They've never been seen to eat anything but fruit and flowers, although it's suspected that they also snack on the occasional passing insect.

Caprines: Goats of the Shadowed Cliffs

Himalayan goral

It is, of course, the case that all animals are continuously evolving, even if some of them don't change much visibly over protracted periods of time. So we can't really point to a modern species and say that this is the kind of thing that everything else in its group evolved from. But some have, at least on visible examination, changed far less from their ancestors than others. They have found some suitable niche in which to live, and, because they're environment hasn't changed much, they've been able to stay more or less the same. It's not that they haven't changed, of course, but just that the changes are relatively subtle.

In the case of the goats, the species that have probably changed the least from the ancestral form are the serows and gorals of eastern Asia. Both kinds of animal have retained a "resource defender" lifestyle, where they find patches of lush food in the otherwise rocky wastes of precipitous cliffs and mountainsides, and defend them from all comers.

Pleistocene (Pt 10): Of Armadillos and Bison

Glyptotherium

When the continents of North and South America collided, shortly before the dawn of the Pleistocene, a range of creatures wandered across the newly formed isthmus of Panama. Most were heading south, giving us such "normal"-looking South American animals as jaguars, ocelots, and grey foxes. The ones heading north were a lot stranger, and many of them didn't do so well in the long term. These include such wonderfully weird creatures as the giant ground sloths, which managed to get as far north as modern Canada before dying out.

But they weren't alone, and not necessarily any stranger than some of their fellow immigrants. The same event that saw the arrival of the ground sloths also saw the coming of the armadillos. Today, there is only one species of armadillo in the United States, and only two outside of South America (the other gets no further north than southern Mexico). But, back during the Pleistocene, there were others, and some of them were not quite what we'd expect today.

Leopard Cubs: The Struggle to Survive

It's obviously important to know, for conservation purposes, how populations of animals are changing. Are they increasing, or decreasing, and how rapidly? A clear factor in determining this is working out how many of them are dying, and ideally, what they are dying of. But we also need to know how many are being born, how often this happens, how likely they are to reach adulthood and have children of their own, and other factors more to do with birth than with death.

Probably the best way to really get a grip on births in an animal population is to study it for several generations, seeing what changes and when, and what factors are particularly important for infant survival. For the majority of small mammal species, a generation isn't a very long time, so it's practical to do that - although the sheer number of such species inevitably means that the great majority have never been studied. For larger, longer lived, animals, its a different matter, and the task can be far more difficult.