Four primates die swiftly and mysteriously at Duke Lemur Center

The Duke Lemur Center has lost four endangered aye-ayes to a mysterious illness that struck within a 24-hour period – a string of fatalities that is unprecedented in the center’s 50-year history.

Two males and two females ages 7 to 28 died in separate indoor rooms at the Durham-based center starting at 4 p.m. Tuesday and finishing early Wednesday. As yet, veterinarians have no explanation for the fast-acting affliction.

“This is the most tragic event we’ve had,” said Greg Dye, operations manager.

“Lots of tears, lots of hugs,” said Bobby Schopler, supervising veterinarian.

Native to Madagascar, aye-ayes are threatened by hunters, habitat loss and the superstition that they are evil and should be killed on sight. Fewer than 50 remain in captivity worldwide, and with these four deaths, Duke’s aye-aye population falls to nine.

With large ears, dark fur, bushy black tails and teeth that grow continuously, they bear little resemblance to the more commonly known ring-tailed lemur popular in “Madagascar” movies. Still, the aye-ayes are symbolic enough of the program to appear in the Lemur Center’s logo. They hunt at night, using their beaver-like teeth and flexible middle fingers to pull insects from tree trunks. Scientists consider them the most intelligent lemurs, which are distant primate cousins to humans.

Most lemurs in Duke’s aye-aye colony were named for horror characters, being nocturnal. Those who died this week are Morticia, nearly 28, the mother of seven aye-ayes bred at the Lemur Center; Norman Bates, 7, Morticia’s son; Merlin, 22, who spent six years on loan at the San Francisco Zoo; and Angelique, 11, who made news in 2005 for being the first aye-aye born to parents also born in captivity.

Video cameras in the aye-ayes’ enclosure showed normal behavior until about 2 p.m. Tuesday. None of the remaining aye-ayes appear to be affected, but staff is monitoring all 250 lemurs every 30 minutes. Public tours do not enter parts of the center where the stricken animals were kept. The center will be open Thursday as normal, by appointment.

Infections seem unlikely in the lemurs’ deaths because the illness came on and turned fatal so quickly, Schopler said. Dye said the investigation will consider ambient air in the enclosure, food, toys and the post-mortem examination.

“The important thing to keep in mind is there’s not a manual,” Dye said. “We’re being very careful not to make guesses.”

Lemur Center veterinarians saw only fluid collection around the heart during necropsies, said staff veterinarian Cathy Williams in a news release. Tissue and blood specimens will be sent out for pathology and toxicology exams that could take at least a week.

Duke’s Lemur Center developed the breeding of aye-ayes in captivity, and many of the lemurs housed in zoos and conservation centers nationwide are Duke natives.

This story was originally published October 26, 2016 at 4:47 PM with the headline "Four primates die swiftly and mysteriously at Duke Lemur Center."