A Northern-banded water snake made its zoo debut last summer in the Reptile House. An Eastern diamondback rattlesnake, not exhibited since 1973, also has joined the collection. Two Chinese alligators, not seen since 1983, will go on exhibit this month.
The collection's decline began during the tenure of Spelman's predecessor, Michael Robinson. He spent 16 years promoting the zoo as a "bio park," with a focus on animals and the plants native to their habitats.
Elena Bell, a fourth-grader at D.C's Capital City Charter School, cleans Rose, a Polled Herford bull, at Kids' Farm.
(Gerald Martineau -- The Washington Post)
Robinson showcased invertebrates and opened the popular Amazonia and Think Tank, with its "O-line" for free-ranging orangutans. But major breeding programs were halted or curtailed, and the hoofed-stock exhibits declined.
"We didn't have the facilities then to bring in new animals, and older animals were dying," Xanten said.
The National Academy of Sciences, which studied the zoo's operations for Congress, said the size of the collection fell 54 percent from 1993 to 2002. Acquisitions declined 67 percent from 1999 to 2002.
In rebuilding the collection, the zoo gets most of the animals as loans or gifts from other zoos or animal sanctuaries. Some animals, especially birds, are bought or traded. The zoo is also used as a holding facility for male zebras, giraffes and red pandas for future breeding elsewhere.
The zoo director gives final approval on acquisitions. If a species is new, the curator does a formal proposal on the impact of getting the animal, including cost and any special diet or exhibit requirements. Zoo veterinarians have to sign off and researchers can request a certain subspecies.
Sometimes, the animal collection changes because the zoo changes. Construction for the new Asia Trail has displaced some exhibits, for example, and the cheetahs and kangaroos will be moved from the area to make way for an expanded elephant facility in 2007.
And sometimes, public passions and curator interest dictate which animals come and go.
Pygmy hippos "are very hard to come by these days," said Elephant House curator Tony Barthel, because many zoos are building underwater viewing exhibits for the more aquatic Nile hippopotamus -- and have let their pygmy hippo breeding programs lapse.
The zoo, determined to keep pygmy hippos in its collection, got a male from Toronto last fall and a female from San Francisco in March, after her mate died.
"It's like a pendulum," Barthel said. "We'll continue looking at what animals are here now and what animals we want to have and what spaces will be available for the short term and the long term."