Tarzan had a chimpanzee, Cheeta, in the movies and a monkey, Nikima, in the source novels. Of course, Tarzan had been raised by apes, and he lived in a jungle, so perhaps his pets were a special case. Then again, Clint Eastwood made a pair of movies about a California trucker with an orangutan, Clyde. On television’s Friends, the hapless Ross owned a spider monkey named Marcel for a season or so. The Man with the Yellow Hat had his hands full with Curious George, but nothing seriously bad ever happened. Why, then, has my wife so consistently vetoed my frequent suggestion that we buy a pet monkey to dress as a cowboy and ride on our dog’s back as a tourist attraction in Central Park? What does she have against monkeys?

Needless to say, my wife is right (and for the record, I was joking). In fiction, apes and monkeys are portrayed as clever, charming companions that are at worst mischievous and at best capable of stealing keys from your captor to unlock the cell where you are being imprisoned. The reality is far less fun: not only do they resist housebreaking and become sick easily, but their propensities for jealousy and misunderstanding human body language can make them turn vicious and destructive with very little warning. The news this past February about a Connecticut chimpanzee’s horrific attack on a friend of its owner underscored that point all too well.

Cheers to the U.S. House of Representatives, then, for passing the Captive Primate Safety Act (HR 80), which forbids interstate trade in primates as pets. Like the Captive Wildlife Safety Act of 2003, which banned similar commerce in lions and other big, undomesticated cats, the primate bill targets only the use of the animals as pets, making exemptions for research, zoos and even helper monkeys trained to assist the disabled. A version of this smart legislation is moving to the Senate as I write this, and I hope that it passes.

A criticism raised against the Captive Primate Safety Act was that monkey attacks hardly constitute a burning threat to the nation. True, but restricting the sale of monkeys and apes would not just protect humans from their hairier cousins, but also vice versa. Keeping these creatures as pets is fundamentally cruel. They are neither little people nor dogs nor something in between, and they do not prosper if kept in the human world. Without anthropomorphizing them, we should mind their capacity to suffer. Indeed, although I personally still accept the use of primates in laboratories as often justifiable, the mounting evidence for their high intelligence and awareness increasingly challenges my confidence in the ethics of that position.

The record of our evolutionary separation from other primates can be read in a comparison of human and chimpanzee DNA, as Katherine S. Pollard discusses in her article. Discover the astonishingly small changes in the genome that distinguish Tarzan from Cheeta. And if you are in the market for an extremely small cowboy costume, I can offer you a bargain.