Casey, 31, a chimpanzee raised in Rockford, Ill., by a gorilla wrestler and a doted-upon resident of the Henry Vilas Zoo since 1995, died Wednesday from an unknown cause following a physical examination, Dane County officials reported.
Zoo staff was described as "shocked and saddened" at the death. The physical was supposed to be routine, said Carrie Springer of the Dane County executive's office, adding that Casey was middle-aged for a chimpanzee.
Casey, who was reportedly able to ride a rocking horse, play football and drink from a bottle at the age of 1 month, was one of 26 chimps raised by Milton and Winona Kling, who trained animals and ran an amusement park.
The death leaves the zoo with two adult chimpanzees, Cookie and Magadi.
Casey died during anesthetic recovery, following the physical exam and "diagnostic procedures," according to Springer. The tests, a collaboration between the zoo staff and the UW School of Veterinary Medicine, included blood collection, cardiac ultrasound and X-rays.
"Casey was a well-loved animal and a favorite of many at our zoo. He will be dearly missed by zoo staff and the community," zoo director Ronda Schwetz said.
Zoo officials said a post-mortem process, part of the Association of Zoos and Aquariums Chimpanzee Species Survival Plan, will be used to determine the cause of death. The data will also be contributed to the Great Ape Heart Project, which addresses cardiovascular disease, a common occurrence in great apes such as chimpanzees, orangutans and gorillas.
Casey's history in Madison, according to newspaper archives, dates to 1995, the year the zoo's primate house opened, when Casey joined Cookie as donations from the Klings, who had raised the chimps — and many others — in their Rockford home. Casey and Cookie's arrival at the zoo was unusual in that they had not been raised in another zoo.
A newspaper article from the time noted that when the chimps first saw the Klings after they were donated to the zoo, the chimps "were so hurt they wouldn't even wave back ... they turned their backs on them instead, in a kind of protest."
Casey was part of a group of chimps, the story said, that had "been the stars in many TV shows, commercials, films, political parties, and birthday parties." The Kling family in 1962 took over Kiddieland Park outside of Rockford. A contemporary history of the park noted the "Klings trained animals, (and) they had several chimps who would entertain at Kiddieland Park and other affairs. The Klings would obtain the chimps when only months old and raise them as one would a child, with diapers, and baby clothes and kept in a playpen until they were old enough to climb out on their own."