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.

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.

The Dog Family: Coyotes and Red Wolves

Coyote

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.

Pliocene (Pt 3): Of Gazelles and Three-toed Horses

Hipparion

The Zanclean Flood may have been a catastrophe of epic proportions, but, so long as you were above where the flood waters eventually stopped, Europe at the dawn of the Pliocene was a fairly pleasant place. The weather was warmer than today, and, apparently wetter too, which might not be what time-travelling tourists would be looking for, but was certainly good news for the plants that were actually there. Where places like Spain, Italy, and Greece are today dominated by... well... "Mediterranean" scrubland, back then they would have been considerably greener. And what's good for plants is good for herbivores.

Especially when it comes to cloven-hoofed animals, many of these would have been animals that would have been, at least in general terms, familiar to us. Not necessarily familiar to us from Europe, though, since, in addition to pigs, bovines, and deer, there were also a number of antelopes. These were mostly members of the gazelle subfamily, although there were others, including some, for example, related to the modern sable antelope. The gazelles included Hispanodorcas, a small and slender antelope with slightly twisting horns, with fossils found in southern Spain. However, some were even closer to the gazelles of today, to the point that, if, like most people, you'd be pressed to tell the difference between a Dorcas gazelle and a Speke's gazelle today (or at least, to know which one was which), you'd probably not have identified these as anything different, either - although at least some of them were smaller than any living species, which might have helped.

What is a Primate?

Brown lemur

In 2012 and 2013, I finished off the year by posting short(ish) responses to questions entered into search engines that had, according to the blogger interface, led people to Synapsida. I didn't do this last year, because the great majority of the questions were ones I had already answered - perhaps an artefact of how many posts there are now at this blog. But somebody did ask "what is the definition of a primate?" and that struck me as something I could expand on at length. So here we are. What is a primate?

The simple, dictionary, definition is "a member of the order Primates". That's obviously a circular, and rather unhelpful, definition, but, then dictionaries aren't the same thing as encyclopaedias. But even it requires picking apart a bit. For a start, note the capital 'P' in the word "Primates". This indicates it's the name of a discrete thing, and not just the plural of the word "primate". It's a Latinate word, like "Rodentia" for the order of rodents or "Proboscidea" for the order of elephants and their extinct kin. Which means that it may not be pronounced the way you think; it has three syllables: Prime-ATE-eez. It literally means "of the first rank", because, you know, anything with us in it has to be of the highest rank. (Hence the title "primate" given to some high-ranking bishops).

The Smell of Success

One of the noticeable features of mammals, when compared to other vertebrates, is that they tend to have a highly developed sense of smell. Most vertebrates can smell, even if, in the case of fish, it's not quite what we'd think of by that term. Indeed, the sense of smell is pretty poor in most fish (sharks are among the exceptions, hence that blood-in-the-water thing), and it's also rubbish in birds, and not too great in many amphibians. It's rather better in reptiles, but the snakes, which appear at first glance to be really good at it, actually do so by cheating (more on that later).

But, by and large, the sense of smell reaches its apogee with the mammals. It's not just dogs that have a far better sense of smell than you do. It's also mice, deer, cats, and many others besides. The mammalian olfactory system is superbly evolved, and this dates right back to the origin of the class. In short, it's usually far better than anything we've got.

Except... um... we are mammals. So what gives? Why are we humans so useless at something that our fellow milk-giving relatives have perfected? Something that, presumably, has a lot to do with the success of mammals as a class?

The Dog Family: Wolves, Dogs, and Dingoes

Eurasian wolf

The best known and most familiar of the species in the dog family is surely the grey wolf (Canis lupus). This is not least because it is the one that we happen to have domesticated, and which most of us see just about every day. Even the wild form is so familiar that there are a great many wildlife documentaries and web pages out there that cover the species better than I can in one blog post, and I don't want to go too much over that ground. But nonetheless, for the sake of completeness, at least some sort of overview is needed here.

The term "grey wolf" is the generally accepted one for the species as a whole. While there are other species that are referred to as wolves, this is the one that we generally mean when we say the word "wolf" without qualification. Most other terms, such as "timber wolf", "steppe wolf", and so on, refer either to groups of one or more subspecies, or are simply alternative terms for the same animal. Once being spread throughout almost the entire Northern Hemisphere (albeit to only a limited extent in Africa), it is unsurprising that there are rather a lot of subspecies.

But how many? That's a question of some debate. I have talked before about how difficult it can be, in practice, to separate one species from another; the problem is even worse when you're trying to count subspecies. One scheme, for instance, has as many as 24 subspecies in North America alone, while another, more conservative, scheme recognises just twelve worldwide. There are a great many opinions that lie somewhere in between.