Wednesday, February 27, 2013

Animal of the week February 27, 2013 -- chomping on the wonder horse

AOTW hardly has its talon on the pulse of current affairs, but I was slow to react to the major UK news event of 2013 because I was convinced that Equus ferus caballus (horse) had already been animal of the week. But having gone back through the entire archive (how I suffer), I can confirm that it hasn’t. So, perhaps, given that so many of us are likely now intimately acquainted with horse through digestion, we should find out a little more about it.

Although there is a superficial similarity between horses, antelopes, and indeed cattle, the closest living relatives of horses are rhinoceroses and tapirs, which together form a group called the odd-toed ungulates (hoofed animals with an odd number of toes). This group is distantly related to the even-toed ungulates—the group that includes pigs, camels, cows, deer, and even hippos and whales. So whales and cows are more closely related to each other than either is to a horse.
Mustangs (feral horses) in Utah, Jamie Jackon wikicommons

Until around 10 000 years ago, wild horses lived across the Eurasia and North America, but at the end of the ice age, the numbers decreased rapidly, and horses vanished from North America and dwindled across the rest of their range. Only the Przewalski's horse (E ferus przewalski) and tarpan (E ferus ferus) survived into modern times: a few Prezewalski's survived in zoos and have now been reintroduced onto the Mongolian steppes, and the last tarpan died in the early 1900s. But their usefulness to humans gave domestic horses a new lease of life: they are now found throughout the world and feral populations have recolonised North America and established themselves in areas where previously horses were never found -- such as in Australia.

Genetic evidence suggests horses were domesticated around 6000 years ago, with most archaeological evidence pointing to a similar date, somewhere around the steps of the Ukraine, Kazakhstan and southwest Russia, although recent archaeological finds suggest that horses might have been domesticated in Arabia some 9000 years ago. The genes of domestic horses tell us that they are descended from a few original stallions, but the domestic stocks were often supplemented with wild caught mares over the centuries. Whenever domestication happened, the relationship between humans and horses is an ancient one. And as a source of meat, milk, hair, hides, transport, and labour horses have played an integral part in the development of human culture, perhaps moreso than any other animal.

Now, I've never intentionally eaten horse, but I'm not too bothered with the idea: if the animal has been well looked after or lived a fairly natural life, if I know what I'm eating, and the species is not endangered and I don't think the animal has suffered unduly in the process of it reaching my plate, I'll pretty much eat anything. The recent horsemeat in beef scandal that has erupted in Europe, however, is an indictment of our food production chains and a symptom of the dire economic straits in which many people find themselves, so that they can be exploited by unscrupulous food manufacturers and supermarkets. But this sort of talk is galloping beyond the remit of AOTW.

Anyway, horses, aren't they great? Let me sum up my feelings with the annotated jingle from a much loved advert. I love horses, best of all the animals (along with all the rest; AOTW has no favourites); I love horses, they're my friends (they're not really, I find horses a bit weird, as though they think they are people trapped in an animal's body, unable to comprehend why they don't have opposable thumbs and can't ride humans or smoke a fag, I guess that's what comes of living so closely with people for so long)!

Tuesday, February 19, 2013

Animal of the Week, February 18 2013 -- Go while you can

A starling, Philip Heron wikimedia commons
This week's animal, Sturnus vulgaris (European starling), is responsible for one of the most spectacular sights of winter, nay of any time of the year: a murmuration. This is when large flocks gather over popular winter roosting sites and put on fantastic aerial displays, with thousands of birds shifting like clouds of smoke, coalescing in tight balls, and then stringing themselves out across the sky, all happening in the blink of an eye seemingly unpredictably.

Testimony to the wonder of such an event, last year an amazing video of a murmuration went viral on the internet. Although you don't have to be paddling a canoe along a country river in the rain to witness one. This weekend I went to see if one would happen in Brighton, and it did, right over the pier, with the sounds of Jamiroquai and the arcade games in the background, I stood mesmerised by the gathering, certainly not as big as the one those girls saw, it was nonetheless a wonderful sight as the sun set with the birds swarming overhead; it was worth putting up with Jamiroquai (muted on my shitty video below; I'm so good to you). In the UK murmuations happen from November to February, so you've a week or so left with a chance to witness this most wonderful vision. Or wait until next year.

Starlings over Brighton, all the dots are starlings
In winter, birds escaping the harsh continental winter swell the numbers of starlings in this country, with our relatively benign, mild climate. These birds gather to benefit from communal warmth and safety in numbers. Small flocks begin to gather around the roosts before dusk, with groups of five, ten, or twenty birds amassing into ever larger aggregations. The largest murmurations can involve millions of birds, but a gathering of a hundred or so birds is mesmerising.

Why starlings form these amazing spectacles is a matter of debate, they probably help to deter predators: any falcon trying to snatch a bird would have to pick one out of large group, and then, thousands of pairs of eyes are better than one. It's thought the individual members of the flock keep track of their six or seven closest neighbours and move with them, vagaries in the distances between the birds mean that the "closest neighbours" can change very rapidly after periods of stasis, leading to the stunning sudden changes in the conformation of the flocks. And if you're a starling, you'd begin evasive behaviour any time one of your seven closest neighbours did -- and that allows the flock to respond rapidly to threats.

Starlings against the Brighton sunset
Perhaps overfamiliar, we often overlook starlings, but they have always been one of my favourite birds. From a distance, dark, drab, and too common to be worthy of inspection, but up close their irridescent green and purple spotted plumage is quite beautiful. Their unmelodic vocalisations warrant further attention too, as they are incredibly complex, a series of whistles, clicks, and mechanical whirrs.

European starlings were one of the bird species introduced to North America by the American Acclimatisation Society. The society sought to bring some familiar European animals to help brighten up the parks and gardens of the USA. While the pheasants and chaffinches didn't really take, the hundred or so starlings released into Central Park took flight, now more than 200 million birds have colonised  North America from Canada to Mexico. And murmurations can be seen across the pond too.

Tuesday, February 12, 2013

Animal of the Week, February 12, 2013 -- Darwin Day

A depiction of the last common ancestor.
If asked whether I'd ever do a mythical AOTW, I’ve always answered “no”. No dragons, no unicorns, no griffins or minotaurs. And while the Androscoggin beast, supposed big cats in the UK, and yetis have had mentions over the years, all were based on real animals. But this week’s animal breaks the only rule of AOTW: it's a work of science fiction, created by phylogenetic wizardry, and lacking a name. It’s the last common ancestor of all placental mammals (the 5000 species or so that give birth after a placenta nourished gestation, rather than lay eggs (platypuses and echidnas) or raise young in pouches (marsupials)).

Using a large database of morphological characteristics of living and fossil mammals, genetic data, and dates from fossil record, research published in the journal Science back-modelled the evolution of mammals since their divergence and determined that the last common ancestor of anteaters, cows, camels, elephants, humans, and whales was a small insectivorous shrew-like thing living about 64.85 million years ago (give or take 100 000 years). The latest estimates for the asteroid impact that did for the dinosaurs (those that aren't birds) is 66.04 million years ago. Researchers had previously thought the splits between major groups of placental mammals happened while dinosaurs still walked the earth. The new research shows that these groups probably split in the first few hundred thousand years after the extinction of the dinosaurs. This is not to say that other groups of placental mammals weren't alive with the dinosaurs, but that they went extinct too, without leaving any descendents, perhaps in the same event.

We already knew that the animal would be quite shrew-like, because most fossil mammals from the time of the dinosaurs were. But according to the analysis tracing back the evolution of thousands of characters described in extant and extinct mammals, the animal weighed 6-245 g, ate insects, and likely gave birth to one hairless baby. Of course, this is science, and it could all be proven to be wrong. But the last common ancestor definitely did exist, and maybe this is what it was like and when it lived.

February 12 is Darwin Day, honouring the man whose work laid the foundations for the science of evolutionary biology, so I think this wonderful story is a fitting AOTW to mark the occasion.