Sunday 22 February 2015

Eau de Raccoon

Most mammals have a better sense of smell than we do. They are able to use this in a range of different ways that suit whatever their particular needs are, such as identifying food, avoiding predators, and so on. But another key use, one that's essentially lost in humans, is as a means of communication. For the most part, this means scent marking, that practice, so familiar to dog owners, of leaving signals around for other members of your species to identify.

There are basically three ways that mammals leave scent marks. There's urinating, leaving dung around, and using glands specifically evolved to create smelly secretions. Having abandoned scent marking, we humans lack proper scent glands, and the closest we get are some modified sweat glands in the armpits and groin that create a special kind of sweat that smells, instead of the usual odourless watery stuff that the rest of our skin makes. And, really, compared with proper scent glands, that's pretty pathetic.

Sunday 15 February 2015

Infidelity Among the Aardwolves?

This year's Synapsida survey of the species in a family of mammals is, of course, that of the dog family. I've already covered wolves and coyotes, jackals will be up next, and then, alongside a few others, you're going to see an awful lot of foxes. What you won't see any of are hyenas.

That's because hyenas, physical appearance notwithstanding, are not dogs. In fact, they're actually more closely related to cats than they are to dogs. (Although they're closer to mongooses than to either, for what it's worth). One of these days I may get round to a description of the hyena family, and how it's different to that of the dogs, but that won't be a terribly long series of posts, because there are only four living species.

There's the one everybody knows, which is the spotted or "laughing" hyena, and there's a couple of smaller, rarer hyenas related to it. And then, there's the aardwolf (Proteles cristata). Aardwolves are, to be honest, pretty strange animals, and there's a lot to be said about them, their feeding habits, and so on. This, however, is not that post. Because, yesterday being Valentine's Day and all, it's time to talk about mating behaviour.

Sunday 8 February 2015

The Dog Family: Coyotes and Red Wolves

Grey wolves are found across the Northern Hemisphere, but they originated in Asia, only reaching the Americas via the Bering land bridge when sea levels were low. Most of their close relatives are also found in the Old World, but there are one or two very closely related species in North America. Of these, by far the more common and better known is the coyote (Canis latrans).

Coyotes first evolved, in North America, during, or shortly before, the Ice Ages, almost certainly from the now-extinct Pliocene species Canis lepophagus. Today, they are found throughout almost the whole of North America, from Alaska to Panama, being absent only from eastern Canada, the Caribbean coast of Central America, and a number of islands. In this respect, they have actually benefited from the presence of humans; before the arrival of Europeans, coyotes did not live anywhere along the east coast of America, and only moved in once we started chopping trees down to make way for cities and farmland.