Tuesday, June 14, 2005

Dolphins with Sponges on Their Noses

This is a really cute story, which also happens to have some very unintentionally funny sections... It seems female dolphins in one bay are using sponges as tools to help them catch fish better. The boys are too busy chasing the women to learn tool use, but the mothers are passing the method on to their daughters.

Dolphin with sponge on her nose.

They found that most spongers shared similar mitochondrial DNA, which is genetic information passed down from the mother. This indicates that the spongers are probably all descended from a single "Sponging Eve". The spongers also shared similar DNA from the nucleus, suggesting that Eve lived just a few generations ago.

But not all the female dolphins with similar mitochondrial DNA use sponges. And when the researchers considered ten different means of genetic inheritance, considering that the sponging trait might be dominant, recessive, linked to the X-chromosome or not, they found no evidence that the trait was carried in DNA. "It's highly unlikely that there is one or several genes that causes the animals to use tools," says Kr├╝tzen.

The story is here: news @ nature.com: Australian dolphins learn to hunt with sponges stuck to their noses.

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