Rabbits in the Ice Ages

The rabbit (Oryctolagus cuniculus) is one of the more familiar mammal species to most people in the developed world, not least because it has been partially domesticated. Moreover, wild and feral rabbits are found across wide parts of the world, living on every continent except Antarctica. They are adaptable animals, able to survive in a wide range of different habitats, from hot semidesert to forests and bleak moorland. So much so, in fact, that, in most parts of the world, they are a pest.

The rabbit is widespread because we humans have spread it, following the initial domestication event in France, no later than 800 AD. This was originally for meat and fur, with pet breeds appearing only from the late 18th century. Rabbits are now found, for example, on Middleton Island, a chilly speck of land 130 km (80 miles) off the south coast of Alaska, and on the Kerguelen archipelago in the Indian Ocean, which is about as remote a place as it's possible to get.

Return of the Rabbits?

This one is wearing a radio collar...

It's abundantly clear that humans have had a dramatic effect on the number and distribution of animals across the globe. (For that matter, by some measures, plants may be doing even worse). There are great swathes of the world where particular animals were once common but are not so any more. Just to take a dramatic and obvious example, Great Britain used to be home to wolves and bears but we don't see those around any more. Those are, of course, widespread elsewhere, but other animals may be less lucky.

In some places, however, a key method in conservation may be reintroduction, bringing animals back to their native habitat, either from elsewhere, or directly from captive populations. This can help restore natural ecosystems, with the return of one originally native species helping others that are now in decline, but have yet to disappear altogether. Again taking Britain as an example, there are currently efforts underway to reintroduce beavers to the country, where they have been locally extinct since the 16th century. Similar programs for other animals exist elsewhere, but the reality is that such efforts are not always successful.

Small British Mammals: Rabbiting About Rabbits

Over the course of the last two thousand years, a number of native British mammals have been driven to extinction. These were mostly the larger ones that were considered either dangerous (wolves) or tasty (wild boar). But we have also managed to introduce a few, mostly smaller, animals that were not originally native to the islands but are now widespread. The grey squirrel, being relatively recent, is probably the best known of these, although the brown (or "sewer") rat is another, only arriving in the 16th century.

Another example was first introduced in Roman times, and so has been here rather longer - but, still, it could be argued that it's not technically native. This is the rabbit (Oryctolagus cuniculus).

Rabbit v. Rabbit

Mountain cottontail

There are literally thousands of different mammal species currently recognised. Most of them are small, and a great many of them can be quite hard to tell apart at first glance. Or even second glance, quite frankly.

The reason that they look so similar is that some body plans have been particularly effective, allowing the creatures possessing them to survive and multiply across the globe. But, if they're so similar, why doesn't one species, over the course of time, drive the other to extinction? Even if one isn't even just marginally better at doing whatever it does than the other (and, since they aren't literally identical, that's unlikely) then sheer bad luck ought to hit one or the other of them eventually.

Miocene (Pt 6): The Coming of the Mice

Palaeotragus

The Early and Mid parts of the Miocene epoch were, for the most part, times when the world was much warmer than it is today. It wasn't a steady pattern, however, and I've already described how the fluctuations in climate, over the course of many millions of years, affected the rodents of Europe. It was a time when the most common small mammals in Europe were not mice and voles, but dormice, accompanied by early hamsters, squirrels, and the gliding eomyids.

By 10 million years ago, however, the colder, drier climate had become locked in for the long term. We know that the forests of Europe changed dramatically at this time, the old subtropical trees, such as figs and palms, being replaced by oak, alder, and elm. Likely as a result of this change in the available food supply, most of the dormice died out, leaving only a few close relatives of the relatively small number of species we have today.

Q&A 2012

This is a synapsid, and not a reptile. Yes, really.

This will be the last post at Synapsida before the New Year, so I thought I'd do something a little different this time. A lot of the hits on this blog are from Google searches, with a few from similar services like Bing. Often, the searches that bring people here are questions, and the blogger.com interface lets me see what those questions were. I don't check it religiously, so I'm sure there must be many questions that brought people here that I've never seen. But, just for fun, this week I'm going to answer some of the ones I have seen.

It's not going to help the people who asked the questions in the first place, of course. And, if anyone asks the question again, there's no guarantee they'll be directed to this page, rather than wherever they were directed before. But what the heck - why not, right?

So without more ado:

Is [X] a Synapsid?

This seems to be among the top two or three questions that bring people to the site. Is a cow a synapsid? Is a tiger a synapsid? What about a monkey? Or a kangaroo? And so on.

Why Rabbits Aren't Rodents

Beaver skull

Over one third of all mammal species are rodents. By almost any reasonable measure, they are the most successful of all the mammalian orders. There are rodents everywhere, in every environment, and on every continent except Antarctica. There are even rodents native to Australia; they're the only placentals of which this is true, other than dingos and bats. They have even adapted, better than any other non-domesticated mammal, to life in urban environments. Indeed, the natural habitat of the house mouse is, pretty much, houses - presumably they used to live somewhere else at some point (river banks, probably), but not really any more.

However, that's going by the scientific meaning of the word 'rodent'. In everyday speech, I've heard the term applied to a even wider range of animals, including such things as shrews, but, most commonly, rabbits. Yet rabbits, along with hares and pikas, are not rodents. On close examination, it doesn't take much to demonstrate that, despite their size and shape, shrews aren't rodents, but rabbits... well, rabbits are pretty rodent-like. So what's the difference?