Sunday, 12 February 2017
An approach that's essentially the exact opposite of camouflage is the "aposematic display", in which the animal has stark, highly visible, colour markings that warn predators it is dangerous. Of course, you really need something to back this up, or the predators will eat you anyway, and, moreover, find you quite easily. Among mammals, among the clearest example of this are the skunks, with their dramatic black-and-white colouring that warns potential predators that they might get a face full of stink if they try anything.
Sunday, 5 February 2017
There are doubtless many zoos across the world, especially in poorer countries, where things haven't improved all that much. But, at least in the West, things have changed significantly. Animals frequently get the chance to roam in outdoor enclosures with grassy environments, rocks and trees to climb, ropes or other toys to play with, and so on. Furthermore, modern zoos do have an important role to play in issues such as conservation - there are species in the world today that would have gone entirely extinct had not some of them been kept in zoos. (For what it's worth, two mammal species - a deer and an antelope - are currently listed as "extinct in the wild" by the IUCN. Re-introduction efforts are underway for both, but it's a slow and difficult process).
Sunday, 29 January 2017
|Otariid (above) and Phocid (below)|
There are three recognised families of pinniped alive today: seals, sea lions, and another that includes only the walrus. All are distinguished by having flippers instead of feet, and a lifestyle that requires them to climb out of the water in order to breed and raise their young.
Leaving the walrus aside, the names I've just given to the other two families (and thus the title of the post) are really a bit misleading. This is because a group of animals called "fur seals" actually belong to what I'm calling the "sea lion family" (technically the Otariidae), and in casual usage, the term "seal" is often extended to pinnipeds in general. As a result, if we really want to be accurate, we need some term to distinguish members of the other family from seals more generally. The technical term for these animals is "phocids", but other commonly used terms include "true seals" and "earless seals".
Saturday, 21 January 2017
Since then, things have changed, giving us a better picture of evolutionary relationships overall. Among other things, the number of animals that really belonged in the Insectivora was whittled away, as we discovered where the things we'd thrown into the wastebasket really belonged. The rump of the group, a genuine evolutionary unit that now goes by the less accessible name of "Eulipotyphla", does, however, still contain its most familiar members, animals such as shrews, moles, and hedgehogs.
Part of the problem is that these are relatively unspecialised mammals, in the sense that they remain broadly similar to what we think the first ever placentals looked like. Moles, of course, have adapted to a burrowing underground lifestyle that makes them fairly distinctive, but this is rather less true of their relatives. This also makes things difficult when we're looking at fossils, and we're trying to figure out just how far down the placental family tree any given suspected small insectivorous animal actually is.
Sunday, 15 January 2017
In the case of humans, of course, much of our social knowledge is built up as children, learning social rules through observation and experience as well as through more explicit instruction. And, while out ability to use language to impart detailed information is something that's essentially unique to us, the need for a suitable environment to fine tune social behaviour isn't something that just arose out of nowhere. Raising an animal in isolation from others of its species might not be as cruel as trying to do the same to a human child, but that's not to say that it wouldn't have some effect on them.
Sunday, 8 January 2017
|Asiatic wild ass|
However, as we know all too well, it was by no means the last time that animals went extinct, let alone the last time that they have been eliminated from some local area. Many of these later extinctions were, of course, due to human activity, especially as we colonised new continents or discovered new islands.
But not necessarily all of them, since the climate has not, in fact, remained constant since the Ice Ages ended. After the sudden thaw that marks the boundary between the Pleistocene and the current, Holocene, epochs, warming continued, but slowed. It reached a peak somewhere around 4,000 to 5,000 BC, and then began a slow cooling that has continued almost until the present. Even that cooling trend has had its fluctuations and reversals, most notably the Medieval Warm Period of the 10th to 13th centuries AD.
Sunday, 18 December 2016
But that debate doesn't belong here, instead, as the year draws to a close, it's time to take a survey of the species of mammal that have been newly discovered this year. Or, more accurately, newly named, since what we generally do these days is find some population of a previously known species that turns out not to belong to it, and to be something else instead. There have, as always, been a fair number of them this year, and there's no guarantee that they'll all stand the test of time, and still be considered valid species in, say, 2026.
My survey is, therefore, inevitably biased, with a just a semi-random sample of some of the species announcements I happen to have come across. Most of them are going to be small animals, since they're easier to overlook in the first place, but there are a couple of quite large ones. And, by "large", I don't mean just "wolf-sized", either.