Saturday, 26 May 2018
This is because mammals are warm-blooded, and need to generate internal heat in order to keep functioning (unless they're hibernating). The smaller you are, however, the more rapidly you lose heat through your body surface, which means that shrews need a fierce metabolism to keep burning enough calories to keep themselves warm. This means that they have to eat almost constantly, but it also means that they want to exert themselves as little as possible while doing so, so as to waste the minimum amount of energy in the process.
Sunday, 20 May 2018
But these are not the only pig-like animals to inhabit Asia. In 1847, Brian Hodgson, a naturalist and former colonial administrator who was living in Darjeeling at the time, described and named the pygmy hog (Porcula salvania), an animal he considered so different from regular pigs in the shape of its teeth and feet that he placed it in its own, newly defined, genus, Porcula. (The scientific name, incidentally, translates as "piglet from the Sal Van", the latter being a forest that only coincidentally sounds like the Latin "silvae" meaning "woodland").
Sunday, 13 May 2018
Sunday, 6 May 2018
Such pay-offs are arguably particularly important for the huge rorqual whales, which feed by lunging at great masses of krill or other small prey and gulping them down. For them, it really matters that wherever they are diving is rich in food, so that they can find enough to offset the effort required to catch it. Quite how they strike that balance should depend on how good they are at diving, which relates to things such as their lung capacity and how much oxygen they need to sustain their bodies.
Sunday, 29 April 2018
But, of course, by no means all bats are cave-dwellers. Amongst the various families of bat, the leaf-nosed bats (Phyllostomidae) of the American tropics are the most varied in terms of diet, and also in terms of their roosting habits and other behaviour. Sure, the majority of phyllostomid species do eat insects and live in caves, as most other bats do. But the group also includes some bats that feed on surprisingly large prey (such as birds) as well as the blood-drinking vampire bats.
It also includes a large number of species that are vegetarian, feeding on fruit such as figs, or subsisting almost entirely on the sugar-rich nectar that they drink from year-round tropical flowers. Many of these fruit-eating species do not live in caves at all, but simply roost in trees - as do the much larger fruit bats of the Old World
Sunday, 22 April 2018
|Visayan warty pig (female)|
And so things remained for a hundred years, until scientists began to look more closely at the animal's genetics. When they did so, they discovered something fairly surprising. Pigs typically have 38 chromosomes (compared with 48 in humans), but it turned out that the warty pigs from the Philippines had only 36 - an entire pair had disappeared, its genetic material shuffled around elsewhere in the genome.
Sunday, 15 April 2018
This, you probably won't be surprised to learn, is as nothing compared to some of the fossil species.