Inbred Wee Smells Weird

Female mice can sniff out inbreds and avoid mating with them, say researchers from the University of Liverpool.

A quick sniff of a male mouse’s pee can tell a randy rodent all she needs to know about his parentage. Females were shown to prefer males who pass a wide diversity of MUPs – major urinary proteins. Lots of different MUPs, the scientists say, indicate a male mouse had unrelated parents.

It is now thought that other animals might also base their mate choices on the protein diversity of urine, evidently the cues that us humans would use (webbed toes, bog-eyes and a perma-gurn) are less obvious in the rest of the animal kingdom.

Pee-sniffing is an important part of a rodent’s life. Not only do they use it to identify potential mates, rats and mice will also avoid areas where predators have urinated.

Rodents infected with the parasite Toxoplasma, however, end up with a nasal nightmare. The parasite, which primarily infects cats, changes the rodent’s behaviour. Toxoplasma-infected mice stop avoiding cat pee, making them more likely to be caught and eaten – it’s the parasite’s handy way of getting where it wants to be.

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