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  • From: Carrie McLaren <stay.free AT verizon.net>
  • To: monkeywire AT lists.ibiblio.org
  • Subject: [monkeywire] Chimp given vasectomy to preserve "primate purity"
  • Date: Tue, 11 Feb 2003 13:44:30 -0500

The Daily Yomiuri (Tokyo)

February 9, 2003 Sunday

Chimp gets snip to stop crossbreeding Alpha ape in Tama Zoo given vasectomy when study shows 'primate purity' at risk

A male alpha chimpanzee at the Tama Zoological Park in Hino, western Tokyo, was given a vasectomy this month to prevent further crossbreeding among species in response to a nationwide campaign to maintain the purity of the nation's primates.

"I felt sorry for him, but there was no other way," said Koichiro Yoshihara, the 57-year-old head zookeeper.

The decision was made by the Japan Zoo Aquarium Association, which discovered more than 10 percent of chimpanzees at the nation's zoological facilities were the product of crossbreeding. In October 2002, the association called on zoos to prevent further crossbreeding by using contraceptives or keeping different species in separate compartments. Kenta, a 22-year-old male chimpanzee, was operated on for the second time in January, after an initial procedure in May. His age is equivalent to the early 30s in a human.

The decision followed a report by Saga Medical School Prof. Kenichi Shinoda and other researchers who performed DNA analysis on 373 chimpanzees at 57 facilities across the nation, the country's first such survey.

The researchers concluded in autumn 2001 that a considerable proportion of chimpanzees in Japan were being kept with other species, causing crossbreeding among species native to eastern, western and central Africa that would not take place under natural circumstances.

The study's results shocked researchers at the Japan Zoo Aquarium Association, who found that 65.1 percent of the nation's chimpanzees were descended from a western African species while 3.5 percent came from an eastern African species. A central African species accounted for 1.1 percent of the nation's chimpanzees, while 11.5 percent were mixed and 16.1 were unidentifiable.

Tests performed on Kenta showed his father was a native of central Africa while his mother was eastern African. Kenta's facial features are more prominent than those of chimpanzees from other parts of Africa, a characteristic typical of eastern African chimps.

As Kenta is an alpha chimpanzee with many mates, the park first tried separating him from female chimpanzees during the mating season. However, this measure disrupted the chimpanzees' social hierarchy as it meant Kenta failed to prove his dominance by mating with several partners.

The park, which keeps 20 chimpanzees, the largest number in the nation, consequently decided to breed only the western Africa chimpanzees. Two female chimpanzees of mixed descent have since been given contraceptive pills developed for humans.

After the vasectomy, Kenta continued to occupy the sunniest spot in the outdoor pen and watch over his clan. He also mates with his partners as he did before the operation.

"Kenta is good at mediating fights among others and he's respected by the female chimpanzees," 39-year-old caretaker Hiroki Nagata said.

On Dec. 15, the first baby chimpanzee was born at the park since the policy of limiting breeding to chimpanzees of pure western African species was implemented. The park hopes the baby chimpanzee will grow up well.

Since Kenta can no longer reproduce, the park is depending for a new generation of chimpanzees on two males descended from the first alpha chimp, Joe, that have been proved to be of western African descent, and three female chimpanzees of the same species that arrived in the park last year.



  • [monkeywire] Chimp given vasectomy to preserve "primate purity", Carrie McLaren, 02/11/2003

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