[monkeywire] Chimps continue to foil birth control
Carrie McLaren
carrie at stayfreemagazine.org
Sat Jun 26 11:11:50 EDT 2004
Posted on Sat, Jun. 26, 2004
http://www.kansascity.com/mld/kansascity/living/9013017.htm?1c
Birds do it, bees do it...
At the Kansas City Zoo, not even monkeys in the trees are doing it
without protection
By EDWARD M. EVELD The Kansas City Star
"In some regards, it's easier to breed animals in captivity than to
keep them from breeding."
Kirk Suedmeyer, director of animal health at the Kansas City Zoo
Gazing at the chimpanzee hill at the Kansas City Zoo, visitors see
chimps doing chimp things, climbing on trees, grooming each other,
roughhousing.
It looks so natural, and that's the point.
What visitors might not realize is that the chimp boys and girls are
allowed to hang out together in captivity because of something
unavailable in the wild: contraception.
In February the zoo celebrated the birth of an eastern black
rhinoceros, the first baby rhino at the zoo in 3 1/2 years. Much
celebration and a naming contest followed. Such hoopla might lead one
to think zoos were working overtime to get their animals to breed.
Mostly, the opposite is true.
"In some regards, it's easier to breed animals in captivity than to
keep them from breeding," said Kirk Suedmeyer, director of animal
health.
Zoos are getting better and better at the latter. They are tweaking
human-style birth control, including the pill and hormone implants.
They're trying out birth-control vaccines. And they're helping to
develop other methods, such as contraception-laced feed for the
hooved animals.
To make it possible for the lions at the Kansas City Zoo to stay
together in one big happy pride, Suedmeyer performed tubal
cauterizations on the two females, Donna and Jean. The pride, led by
Dumisani, includes Jean's three offspring: Nala, Mufasa and Simba.
The idea is that the procedures could be reversed if more lion babies
were ever needed.
The idea and the hope, that is. As with many animal contraception
methods, there are many unknowns.
"It's a technique developed for people, and we're applying it to
animals," Suedmeyer said. "Sometimes it's not the same."
Birth control wasn't a big issue when animals were kept in cages. But
zoos now prefer naturalistic exhibits, allowing animals to display
behaviors typical in the wild. With more social interaction among the
animals, the contraception challenge grew.
For one thing, zoos can't accommodate lots of extra babies.
"There's only so much space," said Liz Harmon, the Kansas City Zoo's
general curator.
Methods such as neutering and spaying are discouraged because they're
irreversible, can alter behavior and have side effects. Zoos still
use gender separation as a means of birth control, especially for
species in which contraception has been less successful.
In some situations, birth control simply isn't needed. The giraffes
in the Kansas City Zoo's Africa area are all females. The gorillas
are males.
The chimpanzees, however, are good candidates for birth-control pills
or implants. In the Kansas City troupe, seven chimps are on the pill
and one has a contraceptive implant. When the implant expires,
Suedmeyer said, that female will be switched to pills.
The implants are effective but pose some problems. Suedmeyer places
the implant in a chimp's back, so the animal won't bother the sutures
needed to close the incision. But troupe mates sometimes find the
sutures and try to pull them out. The same has happened with a pair
of tamarins, with the male monkey trying to take the implant out of
the female.
Suedmeyer has inserted a few extra stitches elsewhere, away from the
implant incision, as a distraction.
"We tried to outwit them a little bit, but it doesn't work," he said.
The pill isn't foolproof either. Chimps are crafty at hiding a pill
under their tongues and spitting it out later. Or, if the pill is
added to their food, it can be difficult to know that they've eaten
it all and received a full dose.
The St. Louis Zoo got a shock last month when keepers discovered that
Merah, an orangutan on daily birth control pills, was pregnant.
Ironically, the zoo in St. Louis is the national headquarters for
animal contraception.
"Yeah, I was pretty proud," said Ingrid Porton, co-director of the
Wildlife Contraception Center, which serves the more than 200
accredited zoos in the American Zoo and Aquarium Association.
Porton suspects the pregnancy was not a failure of the pill but a
"delivery failure." Typically a staff member crushed the pill in
yogurt or honey and watched Merah put it in her mouth. Then she was
given a chaser, more yogurt or a drink, to ensure everything got
swallowed. It's possible, though, that she shared some of the food
with her youngster.
"My suspicion was that she didn't get the full dose every day," Porton said.
While the pill and implants are highly effective, they are not 100
percent. Porton said that a chimp in North Carolina named Ruthie is
famous in animal contraception circles for getting pregnant no matter
what method keepers try.
"She has proved them all worthless for her," she said.
The Wildlife Contraception Center collects data on methods and
results from zoos around the country. Based on that data and other
research, the center makes recommendations as specific to a species
as possible.
New birth control measures are being explored and others, practiced
in some places for years, are being put to the test through research
trials. One recent success, Porton said, is a reversible vasectomy
done on bushdogs, small, stocky dogs from South America.
Gaining attention is an implant called Deslorelin, which represses
the production of reproductive hormones. Zona pellucida is a vaccine
that produces antibodies to keep sperm from penetrating eggs. It has
been used in feral horses and wild elephants in Africa, but questions
remain about proper dosages and how often booster shots are needed,
Porton said.
To study the long-term effects of contraception, a pathologist in
California is examining the reproductive tracts of female zoo mammals
that die. Comparing the animals that have been on birth control and
those that have not will yield more clues about the safety of various
methods, she said.
Generally, the contraception methods are geared toward mammals, a
complicated enough endeavor considering the hundreds of species. With
other animals, such as birds, limiting offspring is more of a
management issue. Nests can be removed or dummy eggs inserted, Harmon
said.
"They will sit on them and not lay any more," she said.
Finite exhibit space isn't the only reason to keep animals from
getting pregnant. Genetic diversity is also a biggie.
With a fairly fixed number of animals at the nation's zoos, officials
want to avoid inbreeding. Successive inbreeding can produce genetic
mishaps, which can result in health problems and death.
"Very few animals come in from the wild now," Harmon said.
Computerized records keep the history of captive animals and their
ancestors. Family trees are developed to show the relationships among
animals.
By controlling who's breeding with whom managers can increase
offspring among family lines poorly represented in the zoo population
and reduce offspring from animals already well represented.
The goal is not to leave parenting to chance.
"We have to have family planning," Porton said.
So the next time the zoo celebrates a new offspring in one of its
rare or endangered species, like the rhino, celebrate. It's a great
success for the zoo staff and for animal conservation.
But, as it turns out, so is most every avoided pregnancy.
To reach Edward M. Eveld, features writer, call (816) 234-4442 or
send e-mail to eeveld at kcstar.com.
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