Holmes points out that even though humans are covered in hair follicles–we have more of them than chimpanzees do–most of our fur grows in an “extravagant topknot” on our heads. In the context of the wider animal kingdom, this is a bizarre, even perverse evolutionary innovation. We also have more sweat glands than any other animal on earth–we can sweat almost a gallon an hour. We don’t think of ourselves as poisonous, but our mouths are as full of noxious, infectious bacteria as is a Komodo dragon’s, and a human bite can be seriously toxic.

The premise of The Well-Dressed Ape is that everybody knows human beings are really animals but nobody cops to it linguistically.

Just talking about ourselves the way we talk about animals is a step toward self-knowledge. “We Homo sapiens,” Holmes writes, “so eager to describe the rest of the world, have been chary about committing our own species to paper.”

Holmes describes us quite wonderfully, and she’s a tireless compiler of biological trivia. Our sense of taste, for example, outperforms a pigeon’s and a tiger’s (it turns out that tigers can’t taste sweetness) but is crushed in turn by that of a lowly catfish, which has taste buds not just in its mouth but all over its body.

In Animals Make Us Human, Grandin is particularly interested in a kind of behavior called a stereotypy: an abnormal action that someone cannot stop repeating. Autistic people often have stereotypies. So, it turns out, do unhappy animals.

Animals Make Us Human is a practical, species-by-species guide to making animals happier, grounded in Grandin’s belief that “all animals and people have the same core emotion systems in the brain.” For most people, her chapters on dogs and cats will be the most immediately rewarding. For instance, she says one reason cats’ emotions are so hard to read is that they have no eyebrows. But there’s a world of insight to be gained from her work on farm animals as well as more exotic zoo animals.

Grandin shows a startling tenderness as she teases out what’s troubling a wolf who couldn’t stop pacing and a herd of antelopes who had panic attacks on their daily walks. (The culprit was a yellow sign; yellow is a scary color for many beasts.)

There aren’t many worse insults for a human than to be called an animal, but these books–which do just that, at great length–are instead strangely ennobling. They make you realize how much effort we expend every day convincing ourselves that we are different and what a relief it is to admit that we are not. It’s lonely here at the top of the tool-using hierarchy–why don’t we let down our fur and join the club? If they will have us, that is. If animals could describe us in return, the results might not be so flattering.