The female chimpanzee at the Philadelphia Zoological Garden died of complications from a cold early in the morning of December 27, 1878. “Miss Chimpanzee,” according to news reports, died “while receiving the attentions of her companion.” Both she and that companion, a four-year-old male, had been born near the Gabon River, in West Africa; they had arrived in Philadelphia in April, together. “These Apes can be captured only when young,” the zoo superintendent, Arthur E. Brown, explained, and they are generally taken only one or two at a time. In the wild, “they live together in small bands of half a dozen and build platforms among the branches, out of boughs and leaves, on which they sleep.” But in Philadelphia, in the monkey house, where it was just the two of them, they had become “accustomed to sleep at night in each other’s arms on a blanket on the floor,” clutching each other, desperately, achingly, through the long, cold night.

The Philadelphia Zoological Garden was the first zoo in the United States. It opened in 1874, two years after Charles Darwin published “The Expression of the Emotions in Man and Animals,” in which he related what he had learned about the social attachments of primates from Abraham Bartlett, the superintendent of the Zoological Society of London:

Many kinds of monkeys, as I am assured by the keepers in the Zoological Gardens, delight in fondling and being fondled by each other, and by persons to whom they are attached. Mr. Bartlett has described to me the behavior of two chimpanzees, rather older animals than those generally imported into this country, when they were first brought together. They sat opposite, touching each other with their much protruded lips; and the one put his hand on the shoulder of the other. They then mutually folded each other in their arms. Afterwards they stood up, each with one arm on the shoulder of the other, lifted up their heads, opened their mouths, and yelled with delight.

Mr. and Miss Chimpanzee, in Philadelphia, were two of only four chimpanzees in America, and when she died human observers mourned her loss, but, above all, they remarked on the behavior of her companion. For a long time, they reported, he tried in vain to rouse her. Then he “went into a frenzy of grief.” This paroxysm accorded entirely with what Darwin had described in humans: “Persons suffering from excessive grief often seek relief by violent and almost frantic movements.” The bereaved chimpanzee began to pull out the hair from his head. He wailed, making a sound the zookeeper had never heard before: Hah-ah-ah-ah-ah. “His cries were heard over the entire garden. He dashed himself against the bars of the cage and butted his head upon the hard-wood bottom, and when this burst of grief was ended he poked his head under the straw in one corner and moaned as if his heart would break.”