Rabbit-sized poisonous rats leverage the same toxins as poison arrows

A giant rodent known as the African crested rat is, despite its adorable appearance, deadly. The rat is the only known mammal to harvest plant toxins — the same kind traditionally used in poison arrows — to protect itself from predators. While researching this unique aspect of the rat's existence, scientists with the University of Utah found unexpected social behavior among the rodents.

The African crested rat somewhat resembles a skunk, and it is able to sequester toxins from certain plants in order to defend itself. This defense method makes the animal special, given that no other mammal is known to have the same ability.

In a new study, the researchers found that the African crested rat also has unusual social behaviors — for one thing, the rats seem to form monogamous relationships and may even assemble their own small families with their offspring.

The study's lead author Sara Weinstein described the rodent as akin to a 'black box.' The poison defense, which was first reported in 2011, is made possible by the Acokanthera schimperi, a plant that is used as part of traditional arrow poisons.

Compounds found in the plants called cardenolides are very toxic to the majority of animals, including humans. This latest study sought to confirm the poisonous rat, but stumbled upon the surprising social behaviors as well. "We initially wanted to confirm the toxin sequestration behavior was real and along the way discovered something completely unknown about social behavior," Weinstein explained.

For this study, the researchers managed to capture 25 African crested rats — the largest group studied so far — and documented around 1,000 hours of behavior on video. Among other things, the observations confirmed that the rats use the plant toxins to protect themselves.