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.
Sunday, 8 April 2018
Clearly, these are creatures that benefit from the group protection that living in herds provides, and, while there's obviously a limit on how large a herd can be before there isn't enough food to support them all, it's not always so clear why the herds should be single-sex. Why, in short, do so many hoofed herd animals practice sexual segregation?
There are a number of theories, and, as is often the case, they aren't mutually exclusive. Nor is it likely that the reason - or the balance of reasons, if there's more than one - will be the same for every species. It's something we have to examine on a case-by-case basis.
Sunday, 1 April 2018
Surprisingly, perhaps, we have, however, named many more fossil species than living ones, and our understanding of penguin evolution is rather better than that of most families of flying bird - which tend to have light and fragile bones that don't fossilise well. Unfortunately, as is often the way, it's the earliest and most interesting part of that fossil history that's most obscure, since, being older, these are the fossils least likely to be preserved.
But that doesn't mean we have nothing from that time.