Wathne says there are trends for roadside zoos, a kind of roadside species du jour. "Right now it seems to be giraffes, because the public can feed them," she says. "And river otters - with some places allowing people to swim with the otters." Big cats and primates, she adds, are common because they're crowd pleasers.
"Really, the only species I can think of that a roadside zoo probably could not get or would be very difficult to get would be polar bear, gorilla, orangutan or rhino," she says.
A zoo home is rarely permanent
It's been some 50 years since Sissy was brought into the U.S. and it's unclear how many animals, like her, are shuffled annually throughout AZA zoos. (Request for comment by the AZA was not returned.) But in 2009, some 2,175 animals were shipped from the Smithsonian's National Zoo alone (most were invertebrates, mainly aquatic creatures such as cuttlefish).
And the standards that AZA zoos have for transport exceed those of roadside zoos.
"When animals are moved from one accredited zoo to another, they are moved for a specific reason," Ron Kagan, director of the Detroit Zoo, told The Dodo. For example, when Detroit's exceptional Arctic Ring of Life was opened in 2001, "the Detroit Zoo received polar bears from a number of other zoos because its facility was much larger than the existing facilities at the time," Kagan says.