09 October 2007

Chimps choose more rationally than humans
+ bonus fun facts & interesting queries


German researchers have demonstrated chimpanzees make choices that protect their self-interest more consistently than do humans.

Researchers from the Institute of Evolutionary Anthropology in Leipzig studied the chimp's choices by using an economic game with two players. In the game, a human or chimpanzee who receives something of value can offer to share it with another.

If the proposed share is rejected, neither player gets anything.

Humans typically make offers close to 50% of the reward. They also reject as unfair offers of significantly less than half of the reward, even though this choice means they get nothing.

The study, however, showed chimpanzees reliably made offers of substantially less than 50%, and accepted offers of any size, no matter how small.

The researchers concluded chimpanzees do not show a willingness to make fair offers and reject unfair ones. In this way, they protect their self interest and are unwilling to pay a cost to punish someone they perceive as unfair.

OK, so whats the diff between an ape and a chimp? a monkey and a gorilla? alligator and a crocodile?

Easy rule: monkeys have tails, apes don't and chimpanzees are apes.

Chimpanzees are our closest living relatives. Monkeys are much more like other mammals than apes and humans are. Monkeys skeletal structure is similar to a cat, dog or other four-footed animal, and they move in the same sort of way. On the evolutionary line leading to humans, monkeys split off long before apes did.

Apes are the members of the Hominoidea superfamily of primates, which includes humans. The Hominidae family also consists of orangutans, gorillas, chimpanzees... collectively known as the "great apes".


chimp


gorillaz


more chimp


monkey

OK asshole, so whats the difference betwixt a crocodile and an alligator?

Well, the first difference between a crocodile and an alligator is that they are from different families of crocodilians. Crocodiles are from the crocodylidae family, while alligators and caiman are from the alligatoridae family. Whatever that means.

In terms of physical differences the easiest way to tell the difference between the two is that a crocodile has a very long, narrow, V-shaped snout, while the alligator's snout is wider and U-shaped. Because of the wide snout of the alligator it packs more crushing power to eat prey like turtles that constitute part of its diet.

The narrow crocodile snout, although still very powerful, is not really suited for prey like turtles but is very versatile for fish and mammals.

Another physical difference between the crocodile and the alligator is that the crocodile's upper and lower jaws are nearly the same width, so the teeth are exposed all along the jaw line in an interlocking pattern, even when the mouth is closed. They also have an enormous 4th tooth on the lower jaw that is accommodated by depressions in the upper jaw just behind the nostrils.
An alligator, on the other hand, has a wider upper jaw, so when its mouth is closed the teeth in the lower jaw fit into sockets of the upper jaw, hidden from view. Only the teeth of the upper jaw are exposed along the lower jaw line. Even the enormous 4th tooth on the bottom jaw, which is exposed in a crocodile, is hidden in the alligator.


Mr. Crocodile


Lady Alligator

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