Rodent kills enemies with plant poison

Hollow poisonous hairs on the back store toxic secretions

African mane rat © gemeinfrei
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The African maned rat has developed a particularly sophisticated defense strategy against dogs, jackals and other predators: it chews the bark of a highly toxic plant and then stores its toxic saliva in the hair of her striking back crest. British researchers have now uncovered this for the first time. If a dog bites the roughly rabbit-sized animal in the back, he can die from it. The acanthic herb used in Central Africa as a poison of the head is strong enough to kill a human in 15 to 20 minutes.

The mane-rat Lophiomys imhausi is thus the first known mammal to procure such a deadly poison from second-hand, the researchers report in the journal "Proceedings of the Royal Society B". Just a mere touch of the strikingly black-and-white patterned hair field is enough to make the heart-damaging poison work. How this penetrates the skin is still unclear. The saliva may contain a substance that facilitates the passage, speculate the scientists around Fritz Vollrath from the University of Oxford. Also unanswered is the question of why the mane rat is immune to the deadly poison.

"The details of this extraordinary relationship between mammal and plant require further research. However, our observations exemplify the evolutionary power of predators to produce very unusual defense strategies in their prey, "the researchers say.

Gray hair hidden under gray fur

Normally, the African mane rat is rather inconspicuous, a long gray coat covers her entire body. However, when attacked, special muscles along her back share her coat and reveal a black and white pattern of previously hidden, shorter hair. These hairs contain the deadly poison, as the researchers now prove.

Images taken in an electron microscope revealed that the poisonous hairs have a double shaft. "The central part of each hair shaft is surrounded by a thin but stable outer cylinder. This is riddled with numerous holes, "the scientists report. display

If the mane-rat spills its saliva mixed with the plant-poison on these hairs, it absorbs the secretion like a sponge. The liquid then dries out to a tough mucus. "The open structure of the hair ensures that 'charged' hair can not be touched without getting in contact with the poison, " say the researchers.

Only the hedgehog shows a comparable behavior

The use of a foreign poison is known among mammals so far only from hedgehogs. These "milking" Hautdr sen the Erdkr te and paint with the slightly poisonous secretion their spines. Such a deadly poison, which had already been on contact, as in the case of the rat-rat Lophiomys, had not been known by suckers before.

"Together with other morphological, anatomical and behavioral adaptations, this is an effective defense that is extremely unusual for a mammal, " the researchers write in their article. (Proceedings of the Royal Society B, 2011, DOI: 10.1098 / rspb.2011.1169)

(Proceedings of the Royal Society B / University of Oxford / dapd, 03.08.2011 - NPO)