In a converted cattle shed in central Kenya, a mischief of rats is getting up to some. Bristling with energy, the salt-and-pepper animals—African crested rats, which look like skunks that tumbled around in a dryer—gnaw on the stalks and leaves of a poisonous plant. Raising the fur on their flanks, the rats use their tongues to lather their bodies with a mixture of spit and toxin. Recently, a team of researchers including scientists from the University of Utah and the Mpala Research Centre in Kenya took a look at the…