The greater mouse-deer is a teeny-tiny little thing, more or less rabbit-sized with legs the size of pencils. (I drew this one’s front legs too big.) The deer, also called chevrotains, live in Brunei, Indonesia, Malaysia, Myanmar, and Thailand. They weigh about 11 pounds, and unusually for deer, they don’t have horns or antlers. They do have big ol’ upper canine teeth, though, that become tusk-like in males.

Here’s an alarming (to me) fact: female greater mouse-deer spend only about two hours between giving birth and becoming pregnant again! They’re pregnant their whole lives. This leads me to ask a question of my biologist readers: are the pregnancies of other mammals as uncomfortable as ours? I’m thinking of morning sickness, varicose veins, hemorrhoids, backache, swollen ankles, etc. Is this unique to humans, and if so, why?

A remarkable thing about greater mouse-deer (which are sometimes called “living fossils” because of how ancient they are as a species) is that they are amazingly good swimmers. Scientists have observed them fleeing predators—say, humans or mongooses—by jumping into the water and staying under for up to five minutes at a time. They’ll swim around for an hour to keep away from a threat. Another Asian mouse-deer species does the same thing, as does an African relative of the species. These observations have lent credence to the idea that whales evolved from deer-like mammals.

Supposedly, greater mouse-deer make good pets. I think they would look particularly cute paired up with an Italian greyhound.

BBC: “Aquatic deer and ancient whales”