SCIENCE -- May 10, 2012 at 1:30 PM EDT
'Oops Babies' Sired by Twice-Vasectomized Chimp
Editor's note: On Thursday's NewsHour broadcast, science correspondent Miles O'Brien reports on the debate over using chimpanzees for biomedical research. First, here's an inside look at one of the sanctuaries profiled in the piece.
At Chimp Haven, chimpanzees roam freely through the pine, sweetgum and huckleberry forest. They pluck fresh buds from the highest branches of the elm trees. They forge friendships and build nests. In fact, they're encouraged to be wild in all ways but one: breeding.
But lately there's been a strange, Jurassic Park-like turn of fate.
Despite a strict no-breeding rule and extreme efforts to stop it, the chimps are having accidental babies. Five years ago, Tracy was born in the sanctuary's forest. And this year, on Valentine's Day morning, 29-year-old Flora was found in an indoor area holding and nursing a newborn chimp. Immediate pregnancy tests on all the female chimps found 42-year-old Ginger also knocked up with a summer due date.
The births occurred even though all males in the group were vasectomized. Some were even twice-vasectomized, like Conan, father of the new baby, who they're calling Valentina Rose. DNA tests show Conan was also the father of 5-year-old Tracy.
With Chimp Haven devoted to reducing the number of animals in captivity, new babies are a problem. The facility is essentially a retirement home for the chimps who were used in research or entertainment or were raised as pets. Its mission is to provide lifetime care for the animals. And chimp care isn't cheap: Caring for one animal costs as much as $15,000 a year.
"Our entire goal is to take care of chimpanzees that are no longer used in medical research," said Linda Brent, founder and director of Chimp Haven. "Our goal isn't to create more chimpanzees that need help. ... So every time there's a birth here, in essence, it takes money away from somebody else who might be in need."
(Brent explains more in the interview with Miles O'Brien at the top of this post.)
In response to the latest pregnancies, Raven Jackson, the facility's veterinarian, sprung into action. She immediately put all of the female chimps on birth control, a 28-day pill regimen. And on suspicion, she embarked on the task of inspecting the vasectomies of all the other males.
It's a good thing she did. Of the 13 males examined, 12 of the vasectomies had regrown. Translation: Almost every male chimp at Chimp Haven was fertile and capable of breeding.
"What I'm seeing is complete regrowth," Jackson said. "I'm shocked that I'm opening them and they're all intact."
In humans and chimps, a vasectomy involves severing the vas deferens, the narrow tube that carries sperm from the testicles to the urethra. The original procedure involved snipping a one- to two-inch section from the vas deferens and cauterizing the ends. But in some cases, those ends have proven able to regrow and reattach within five years.
"You have two ends that want to find each other and biology that wants to reproduce, so that's what happens," said Jocelyn Bezner, veterinarian at Save the Chimps, a Florida-based sanctuary with 272 chimpanzees. Bezner, who had similar problem among her animals -- a 30 percent rate of regrowth -- brought in a human urologist to remedy the problem. He taught her a new procedure, which she then taught Jackson.
The new procedure starts the same way but then involves suturing one end of the severed vas deferens -- the end attached to the urethra -- into the body tissue to prevent regrowth from occurring.
"I'm glad we found a technique able to do that," Bezner said. "We want the chimpanzees to be able to have sexual activity. It seems to lessen fighting and be part of their social interaction. That's why we don't neuter them."
Scar tissue from the previous vasectomies makes it a somewhat difficult procedure, Jackson said, but she added that it doesn't appear to be painful for the chimps.
"Really, we're just now seeing outcome of early vasectomies done," Brent said. "There's a time lag, and they're growing back." This is information that should be shared with anyone who works with captive apes, she said, adding that they hope to publish the results soon.
"We've always known that in so many ways, chimps are so resilient. This is another example of that."