Life and death at the zoo: Oldest chimpanzee euthanized

PORTLAND, Ore. - On the same day the Oregon Zoo welcomed a newborn elephant to the world, zookeepers also said farewell to the oldest animal they had in captivity.

Zoo staff decided to euthanize Coco the chimpanzee after she suffered a "debilitating health setback."

Coco was around 60 years old and had been at the zoo for the last 50 years. The median life expectancy for a female chimp is 31.7 years.

"Coco was quite elderly for a chimp," primate curator Jennifer Davis said. "Unfortunately, she suffered a debilitating health setback earlier in the week and her quality of life had diminished to the point where euthanizing her was the most humane option."

Coco was born in the wild and came to the U.S. as a pet, which was legal at the time. She was donated to the zoo by her owner in 1961. She was the second oldest chimp in any American zoo.

The zoo provided the following history of Coco:

"In the 1970s, Coco was part of a study that changed the way chimpanzees born in zoos are raised. At the time, about half the breeding population of zoo-born chimps in the United States had been born and raised in Portland, and researchers began questioning why zoo-born chimps in the rest of the country weren't reproducing more.

"Over the next 15 years, research at Portland's zoo showed that chimps who were cared for by their mothers for longer periods were significantly more likely to exhibit natural breeding behaviors by the time they reached adolescence and adulthood.

"Based on this research, Dave Thomas and Nancy King Hunt co-authored a chapter on early rearing for the Association of Zoos and Aquariums' Species Survival Plan for chimpanzees. Accredited zoos across North America subsequently adopted the new standards, keeping young chimps with their mothers for at least three to five years.

"During this time, the zoo also had a strong connection to renowned chimpanzee expert and conservationist Jane Goodall. In 1973, Goodall had been featured in a public service announcement endorsing the formation of the zoo's governing agency, Metro and she was instrumental in helping the zoo find support to fund a large outdoor area to house all its chimps together. In 1979, Goodall visited the zoo with her husband, Derek Bryceson, director of the Tanzania National Parks. Other prominent zoo visitors during this era included President Jimmy Carter and his wife, Rosalynn.

"Coco is survived at the zoo by two of her daughters Delilah, 39, and Leah, 38 along with their troop-mate Chloe, who is around 43."