The deer mouse (Peromyscus maniculatus), sometimes called the field mouse, is a little bigger than a house mouse. It's easily ...

Four rodents in the U.S. are known to carry it: the deer mouse (Peromyscus maniculatus), white-footed mouse (Peromyscus leucopus), marsh rice rat (Oryzomys palustris), and hispid cotton rat (Sigmodon ...

These sperm hooks are found not only in animals in the Peromyscus genus, which Hook studies, but across almost all mice—which is why it’s so surprising that scientists don’t know what they’re for.