Sunday, 14 January 2018

The Strong, Silent Type?

Compared with many other kinds of animal, mammals can often have complex social lives. While many kinds of mammal live in packs or herds, with sophisticated dominance hierarchies and the like, the most complex of all mammal societies (at least as defined by we humans) belong to species belonging to one of just three mammalian orders. It's likely no coincidence that these also happen to be the three orders with the proportionately largest brains.

Perhaps the most obvious of these are the primates, the group that includes our own species. Many species of monkey have flexible social structures where members join and leave groups, adjusting their social positions accordingly, and relying on sophisticated interactions with one another to keep everything functioning. However, the social lives of cetaceans (whales, dolphins, and porpoises) can be equally complex, with, for example, multi-level associations between different pods. The third group to exhibit this sort of behaviour are the elephants.

Sunday, 7 January 2018

Making Hay on a Mountaintop

As I write this, the weather across much of the US is not great. According to Google, it is, right now, -12°C (10°F) in Washington, DC, and that's ignoring the effects of wind chill. And it's a nippy 16°C (61°F) in Arizona... okay, so perhaps that latter one isn't the best example. But the point is, this is harsh, and, if it isn't fun for humans, then it isn't for wild animals, either.

Indeed, winter in general is a tough time for animals living in temperate climes, as much due to the lack of food resources as to the need to shelter from the cold. There are a number of different strategies they use to mitigate this time of enforced starvation. Some animals, of course, simply brave the conditions, using thick winter coats, and perhaps some means of digging out food from beneath a blanket of snow. But others take more active steps, and there are basically three ways of doing this. One is to hibernate, so that you don't need much in the way of food until the spring. A second is to simply move elsewhere, either migrating to warmer climes or, if you live on a mountain, just heading downhill a bit.

A third approach is to collect food in the autumn and then store it somewhere through the winter, so that you have ready access to it. This, naturally, poses a number of problems. You have to remember where you put the food, hope that somebody else isn't going to find and eat it, and ensure that it doesn't spoil. Even so, a number of smaller mammals do exactly this, and it's clearly something that works for them.

Sunday, 17 December 2017

Prehistoric Mammal Discoveries of 2017

Albertocetus meffordorum, the post-cranial anatomy of which
was described for the first time this year.
At the end of each year, I do a slightly different post to wrap up the blog for the season. The format of these has changed over the years, and this year, again, it's time to do something slightly different from previous occasions. Not that there haven't been some interesting new species discovered this last year, with, to my mind, the Skywalker gibbon (Hoolock tianxing) being the stand-out example. This was announced early in the year, having been discovered in the Chinese/Myamar border region by a group of researchers who were fans of a certain science fiction franchise ("tianxing" literally translates to "sky-walker" in Standard Chinese), and is likely already endangered.

But this year, instead of discussing just how many new kinds of bat we discovered in the last twelve months, I'm going to note that my posts on fossil mammals tend to be more popular than those on the living sort, and take a look at a partial assortment of scientific papers published on this subject in the last year that, for various reasons, didn't end up in my regular blog posts. So here goes.

Sunday, 10 December 2017

Short-Necked Giraffes of Spain

The giraffe family is a classic example of a mammal 'family' that consists of very few living species. Giraffes are sufficiently distinctive, and, arguably, odd, that they clearly deserve a family of their own, yet there just aren't very many of them. Exactly how many living species there are in the family is currently the subject of a dispute, since there is good reason to suppose that the animal we actually know as "a giraffe" represents multiple species, but many researchers feel that the hard evidence for that supposition is lacking. What we can say is that, apart from the giraffes proper, there is only one other living species in the family - the okapi.

Fortunately, being large creatures, prehistoric giraffes tended to leave reasonably decent skeletons behind. They're distinctive in more ways than you might think, too, having, for example, a particularly odd canine tooth that ends in two or three (admittedly small) points, rather than just the one. So our knowledge of fossil giraffes is fairly good, and it turns out that there were a lot more species of them in the past than there are today - they were once a larger, and more widespread group.

Sunday, 3 December 2017

Counting the Clouded Leopards

There's no definitive answer to the question of which group of wild mammals have the greatest public popularity, but there can be little doubt that the big cats are up there with the best of them. They are a popular subject for wildlife documentaries, and, for example, the BBC's Big Cat Diary ran for nine seasons (some under slightly different titles) between 1996 and 2008.

Because they're the easiest to film, living as they do in relatively open and accessible terrain, four species of big cat get the lion's share (ahem) of the televisual attention: lions, tigers, leopards, and cheetahs. But, of course, these are not the only ones. Taking a wider look, the cat family as it exists today has two major branches: the big cats, or "pantherines", and the "true felines". That latter group is the larger of the two, including not only the domestic moggie and such species as the ocelot, but even some relatively large animals, such as servals and bobcats. Perhaps more surprisingly, both the puma/cougar/mountain lion and the cheetah actually turn out to be "true felines" when you look at their evolutionary ancestry - in fact, they are closer to domestic cats than they are to, say, lynxes.

Saturday, 25 November 2017

Miocene (Pt 4): Bear-Dogs and Dog-Bears

Amphicyon
Many of the animals we would see in Early Miocene Europe, were we able to visit, would be of broadly recognisable types: deer, pigs, antelopes, rhinos, and elephant-like mastodons. True, many of these are nor animals we would expect to find in Europe today, and the individual species were, of course, different from the modern sort, and in some cases quite dramatically so. But they at least have identifiable relatives today.

But all of the animals I've just mentioned are herbivores. Yet, when it comes to the larger predators of the day, we instead find that most of them were rather different, lacking close modern relatives. While more recognisable carnivores did, in fact, turn up as the Miocene progressed, at least in the beginning, the majority were survivors from an even earlier time, before many modern kinds of animal had arisen.

Sunday, 19 November 2017

The Barcoded Droppings of French Water Moles

How do you know what a given species of animal eats in the wild? The question is of more than merely academic interest. In addition to its obvious relevance to zookeepers, it can also help us to understand how a particular ecology works and what sort of harm we might do it by changing something. In the case of endangered species, it can also be important for conservation, since it's no good protecting the animal if you don't also protect its food supply.

The simplest way to answer the question is probably just to follow the animal around at a suitable distance and watch what it does. In the case of large, visible animals such as lions or moose, this is likely an effective, if somewhat time consuming, method. But it works rather less well with something small or difficult to observe, especially since small mammals spend most of their time eating. (They have to, to maintain their body temperature, since small objects lose heat more rapidly, and they need, proportionally speaking, a lot of calories).