Monday, February 26, 2007

Animal of the Week February 26, 2007 -- like a little baby human with bloodlust and hair

Well Chaps,

The whole colossal squid thing is so 2005 (, so with the discovery of stone age tools and more recently a manufactured spear, I have no choice but to make this week's animal of the week Pan troglodytes (chimpanzee).

The discovery of 4000 year old anvils and hammer stones and traces of smashed panda nuts in Ivory Coast reported in Proceedings on the National Academy of Science a couple of weeks back, was a fantastic finding—it appears that when most humans were getting to grips with stone tools and agriculture, the chimps were developing ballet... they had a nutcracking suite.

No? Alright.

This week, it emerges that US scientists in Senegal have witnessed a chimpanzee making and using a spear to kill a bushbaby. Well known for fishing for termites with thin sticks and hunting monkeys in troops. This is the first time that a non-human animal has been observed making and using a tool to hunt for meat. The female took a thin branch, appeared to work one end to a point with her teeth, then jabbed it into a hole in a tree. At first the researchers though she was trying to fish out a beetle grub, but after a few stabs, she broke through to the hollow in the tree and pulled out the well and truly stabbed body of a bush baby. Although successful hunting was observed only once, researchers say several females were seen attempting to hunt in this way.

Now, most hunting by chimpanzees is done by the males, but most tool use by females. Anthropologists reckon that this discovery suggests that females might have also been integral to the development of tool use for hunting in human evolution too. Interestingly, these particular chimps live in savannah mosaic habitat, similar to that in which the human lineage is first presumed to have broken away from that of chimpanzees.

Perhaps, the ancestors of chimps and humans also used tools and that both species have inherited this same behaviour. Personally, I reckon the behaviour has evolved indepedently, if the chimps had really been using these sorts of tools for the past 5-8 million years, why haven't they got to a more advanced stage with it? 2.5 million years ago species of Homo were crafting bone tools and stone axes: have the Pans really not progressed beyond sticks and flat stones in all that time?

Mind you, give them time, and I can see this going the way of humans: it just seems natural that the females should send their tools out hunting. Girls, you know what I'm talking about (obviously that needs to be delivered by a large American lady on a housewife-oriented daytime show).

Sorry, I'm way off the mark this week.

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Monday, February 19, 2007

Animal of the Week February 12, 2007 -- Funny little frog in your throat

Happy Chinese New Year! I have already done pigs, look, there they are.

So this week's animal of the week is not inspired by the Chinese zodiac. Rather, it is Rheobatrachus silus (platypus frog, southern gastric brooding frog). This tiny Australian frog sadly is no longer with us, but until the early 1980s the Blackall and Conondale Ranges in Southeastern Queensland, Australia, rang with the chirruping of thousands froggies going a courting. Small, green, and quite froglike, they would be unremarkable but for their novel approach to reproduction.

Once her clutch of eggs was fertilised, the female would proceed to eat them. But rather than being dissolved by stomach acids, a compound secreted by the eggs switched off the female's normal digestive function and there the eggs developed. Tadpoles then hatched from the eggs and developed into little froglets. The female could not eat while brooding her offspring and her stomach would swell to fill nearly the entire body cavity, to accomodate the froglets. When the young had developed into fully formed little frogs, the female then would vomit up her children ("midwife, can I have a glass of water, I have a froglet in my throat")!

If surprised or threatened, the gravid female could vomit up her young at any time, and the young could mature successfully outside of the body. Although they laid about 40 eggs, only 20 or so young would ever hatch, perhaps the earlier eggs were digested and were sacrificed in order to switch off the usual gastric machinations, or perhaps the tadpoles and froglets used them as a source of food whil confined to the maternal belly.

I am not the only person captivated by these bizarre things, I found this on a site dedicated to refuting evolutionary science with the argument of irreducible complexity. Although it is an old piece, there argument is slightly undermined by the last sentence of the first para, the frogs have not been seen since 1981 and are listed as extinct by the IUCN.

"The miraculous reproduction system of Rheobatrachus silus explicitly invalidates the theory of evolution, since the whole system is irreducibly complex. Every step has to take place fully in order for the frogs to survive. The mother has to swallow the eggs, and has to stop feeding completely for six weeks. The eggs have to release a hormonelike substance to neutralize stomach acids. The addition of the extra protein-rich yolk to the egg is another necessity. The widening of the female's oesophagus cannot be coincidental. If all these things failed to happen in the requisite sequence, the froglets would not survive, and the species would face extinction [PH: face it, they're looking at it's rear view].

Therefore, this system cannot have developed step-by-step, as asserted by the theory of evolution. The species has existed with this entire system intact since its first member came into existence. Another way of putting it is, they were created."

Not really a believer in that view myself, but I'll leave y'all to make up your own minds.


Peter Hayward
Head Keeper
Animal of the Week

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Monday, February 12, 2007

Animal of the Week February 12, 2007 -- Bird-eating bats

This week's animal of the week is the most large of all the bats that live in Europe and the only bat in the whole world that catches birds in mid-air. For this week's animal of the week is Nyctalus lasiopterus (greater noctule bat).

50 g in weight and a wingspan of 45 cm might not seem that big, but compared with Europe's other scrunchy faced insect guzzling flying furballs, most of which are no bigger than a ping-pong ball, the greater noctule is a gargantuan bat. And insects do not quite satisfy their giant appetite.

Fortunately for the greater noctule bats, they live on migratory routes of small brown songbirds such as wood warblers. The wood warblers and the like think they are being smart by flying at night and avoiding the birds that might otherwise try to snaffle small flying things. But the world's only known mammalian aerial predatory carnivore has a different idea. Scientists investigating these leatherwinged beasts have found a large amount of feather remnants in their droppings, especially during the autumn migration when the number of birds passing through is greatest.

Unlike other noctule bats, which are better adapted for forest flying, these are well adapted to open environments and their echolocation is set at a frequency above that audible to the birds they hunt. Clever bats.

Monday, February 05, 2007

Animal of the Week February 05, 2007 -- Philistine fish

Good Monday mes petit choufleurs,

It is indeed that time of the week again. And while there have been plenty of animals in the news that I could opt for (turkeys[done], quagga mussels[there's still a couple of cm left in this barrel], and killer whales in Edinburgh), as they say on the internet, meh! This one hasn't been in the news but it (like all the animals) is worth it; this week's AOTW is Epinephelus itajara (itajara, goliath grouper, jewfish).

Goliath groupers are potentially huge reef fish that can be found in the eastern Pacific, the Caribbean, and the west coast of Africa. They can weigh in excess of 400 kg and reach lengths of well over 2 m, although 40 kg is a more typical weight. With their huge gaping mouths and impressive size, they eat pretty much what they like, although lobsters and other large crustaceans form a large part of their diets. In this week's picture, the fish has been placed next to an American to give you some impression of its size.

Most female goliath groupers are small, and most males are large, in fact, all the really large groupers are male. This observations suggests that like other several other species of grouper they are protogynous, that is, they start out their lives as females, and only when they mature or reach a certain size, do they become male. So there are a few very large males. Once a popular food and game fish, the goliath grouper has been protected since the early 1990s and is globally critically endangered. Where they are plentiful goliath groupers can still be caught. Although they are best approached with caution: a spear fisherman was dragged into a cave and drowned by a large one last year.

In 1991, the American Fisheries Society felt that the name jewfish might be offensive, so they renamed it the goliath grouper after the Philistine champion thwarted by the Hebrew hero in the story from the Old Testament and Qur'an. Perhaps they chose to name the fish after the famous philistine giant because of its size, although I like to think the rebranding is because of the fish's disregard for high-brow culture.

Until next week my dears,