The Pig Family: Suids, Suines, and Swine

The pigs occupy an an interesting position in the mammalian family tree. The pig family, or Suidae, belongs to the order Artiodactyla, consisting of the cloven-footed mammals and a few of their closest relatives. (I will, at this point, note that I'm going to be using "artiodactyl" in the traditional, non-molecular sense, in this post. Paraphyly be damned, at least for today.)

This is unsurprising, given that pigs do, indeed, have cloven hooves. However, there are other features that almost all artiodactyls have in common, most significantly, that they are purely herbivorous animals with multi-chambered stomachs that they use to "chew the cud". Pigs, however, do not, and while they may not be the only non-ruminating artiodactyls, they are by far the most species-rich group to fit this description.

Traditionally, this was thought to be because they are more "primitive", having evolved before their relatives got round to developing more complex digestive systems. In a more modern way of looking at things, we'd instead note that, compared with other artiodactyls, pigs are omnivorous; they haven't developed more efficient ways of digesting tough plant matter because they don't need to. That they've survived as well as they have, evolving over many millions of years without ever being wiped out, shows that this has been a pretty successful tactic for them.

Miocene (Pt 5): Hyenas in the Treetops

The first hyenas somewhat resembled this African civet

When we think of prehistoric carnivorous mammals, the first image that probably pops to most people's minds is that of sabretooth cats. It will therefore be no surprise that, were we to visit Middle Miocene Europe, one of the most widespread carnivores that we would find would be a moderately-sized cat-like animal with enlarged, serrated canine teeth in its upper jaw. What might be a little more surprising is that it wouldn't actually be a sabretooth cat.

The animal was called Prosansanosmilus, and it is known to have lived at least across what is now western Europe, from Spain to Germany. It, or its immediate ancestor, had probably first evolved in northern Africa, and arrived in Europe not long after that continent had collided with its northern neighbour - one of many animals to cross over as part of the so-called "Proboscidean Event". In life, it would surely have looked much like a cat, albeit with shorter legs and flatter paws less suited to pouncing and other rapid movement. But, in fact, it was not a cat, but a member of a family that, like the bear-dogs, no longer exists; that of the barbourofelids, or "false sabretooths".

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.

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.