Saturday, 30 January 2010

Butterflies of Bristol 13: More newcomers

A few new species have just come in and are awaiting emergence in the butterfly house. If you are a regular visitor, drop by and see if you can find them…

Heliconius doris

H.doris has four named subspecies, ours is the Costa Rican H.doris viridis. In addition to the sub-specific differences, populations are polymorphic in parts of their range, with the upper side of the hind wing being blue, green, or red. The larvae are gregarious and feed on Passiflora vines in the subgenus Granadilla – P.acuminata, P. serratodigitata and P. laurifolia are recorded.

Monday, 25 January 2010

January Research Colloquium: Thai Bats, past, present, and future

This year’s series of monthly research presentations started with a very interesting report by Alice Hughes, who is a PhD student at the University of Bristol and one of our volunteers.
Bats as a group are hard to study, as they are hard to locate or observe, and are consequently much neglected even in areas where there is a lot of interest. The UK for example has a well-developed network of bat study groups – I went on a bat walk led by one towards the end of last year where we used bat detectors to track Common Pipistrelles and Noctules in the middle of Bristol. The only tropical bats that have been studied in much detail are the various fruit bats, and they are not typical of the majority of species, being mostly large, vegetarian, and roosting in many species in large colonies in the open.

The current list of species known from Thailand is 121, and many more probably remain to be identified (many bat species can only be told apart by their ultrasonic calls without DNA analysis). Each of these species has its own preferred set of environmental conditions, which explains their often restricted ranges. Alice has been studying the bats of Thailand in order to obtain a predictive envelope of the various conditions required, to enable the extrapolation of how species will fare in the future, and have fared in the past, under different climate conditions. Probably the most well known is the Bumblebee Bat, Craseonycteris thonglongyai. Interestingly, the Thai population appears to have slightly different requirements to the one in nearby Myanmar, which is also genetically distinct, although whether this means there are actually two species or simply local subspecies is unclear.

Sunday, 17 January 2010

A Hippo's Tale

As I have done posts now on all the other hoofed animals we currently have at Bristol, I thought I would finish by a post on the sole remaining species, the Pygmy Hippopotamus.
There are only two species of Hippopotamus alive today, our own Pygmy hippos and the large River Hippo. As these are both confined to Africa, you might think that has always been the case. Go back as recently as the end of the last Ice Age however, and hippos could be found in many parts of the Old World, with a range at one time extending as far east as Java.
Hippos first appear in the fossil record in the Miocene, about 15 million years ago, when they already are plainly true hippos. Their ancestry is unknown, but it is generally believed that they derive from a group of fossil herbivores called the anthracotheres, which are an ancient group of both terrestrial and semi-aquatic animals that probably lost out to hippos, surviving in Asia until about 2 million years ago. Recent DNA work has shown that hippos are in fact the closest living relatives of whales, and as the oldest known ancestors of whales date back at least 60 million years it is plain that the hippo lineage has been around for a very long time.

The River and Pygmy hippos have quite different ecology, as they actually represent two distinct lineages.

Sunday, 10 January 2010

A very dear deer – the Southern Pudu

The only deer we have on show at Bristol (when they deign to show themselves at all) is the Southern Pudu, Pudu puda. One of only two species in the genus (the other is the Northern Pudu, Pudu mephistopheles} it is the world’s second smallest deer. (The Mouse Deer in Twilight World are technically Chevrotains, not true deer). The only smaller species of deer is the Northern Pudu). It is about half the size of the Southern Pudu, and there are none in any zoo affiliated to the World Zoo and aquarium Association (WAZA).

Pudu are derived from larger animals very similar to the North American White-tailed deer, which invaded South America about 4 million years ago. The same group also crossed the Bering land bridge into Eurasia, giving rise to the British Roe deer, which in many ways has very similar behaviour to Pudu although it is somewhat larger.

Tuesday, 5 January 2010

Tapir-ing off

A few years ago I was chatting with some visitors to Bristol Zoo who mentioned they had some very unusual animals back home. They were retired farmers, and when a local wildlife park closed they had bough a pair of Brazilian Tapirs. Not only had they kept them successfully, they had even bred.

While I would certainly not recommend that anyone else try this, it gives some idea as to the adaptability of the species. In fact tapirs have been kept and bred in zoos for many years, and they can be seen in many animal collections around the world.

So what are these strange creatures? I have overheard many explanations from visitors, from the understandable (“they look like pigs a bit”) to the downright strange (“they’re anteaters dear”). In fact they are of course hoofed animals, most closely related to horses and rhinoceroses, although the oldest fossil tapirs go back a very long way, so they are not especially closely related to anything.