Five Meerkats Mysteriously Die at the Philadelphia Zoo

The sudden deaths of five meerkats at the Philadelphia Zoo this month have stunned zookeepers and officials, and a dye used to mark the animals might be to blame.

The meerkats, two males named Ari and Kgala and three females named Lula, Nkosi and Nya, were siblings and arrived at the zoo in 2013, said Rachel Metz, the zoo’s vice president of animal well-being.

The three female meerkats died on June 1, one of the males died on June 3 and the other male died on June 12. None of the meerkats had experienced any serious health issues before, a zoo spokesperson said.

The deaths came as a shock to zoo officials, who said they had never had issues with the dye in the past.

“This is a dye we had successfully used for 30 years, and obviously something changed here,” Ms. Metz said. “We’re trying to figure that out. We have a pretty robust internal and external fact-finding process we’re going through.”

An in-house necropsy, an autopsy for animals, showed signs that the deaths could have been related to an ink used to mark small animals for identification. Zoo staff members sent samples of the animals to the University of Pennsylvania School of Veterinary Medicine for further toxicology reports to confirm the cause of the deaths, but results could take weeks, said Ms. Metz.

Since the meerkat deaths, the zoo has ceased using the dye on small animals like titi monkeys and lemurs, Ms. Metz said. Staff members have shifted to using other methods of identifying animals, such as tags and monitors. It is also working with the Associations of Zoos and Aquariums, a nonprofit and accrediting organization, to inform other zoos about the deaths in case they are using the same dye.

The mysterious nature of the deaths has taken a toll on the zoo’s staff members, Ms. Metz said.

“Our animal care staff often spend more time with the animals at the zoo than their own families at home and their own pets,” she said. “There is a real bond between the staff and the animals, and obviously they are devastated by this.”

The Philadelphia Zoo houses animal health care facilities and participates in a number of conservation efforts, including one for golden lion tamarins.

Meerkats, slender-tailed creatures with pointy faces, are members of the mongoose family and are native to Botswana, Mozambique, South Africa and Zimbabwe. They typically live in large packs called mobs, which can contain dozens of individuals. They exhibit sociable and animated behavior, which was documented on “Meerkat Manor,” a popular Animal Planet television show that ran from 2005 to 2008.

Meerkats are also known for their teamwork when hunting for food and looking out for predators as well as for sheltering in extensive underground tunnels.

There are no remaining meerkats left at the zoo, Ms. Metz said, but officials plan to work with the Associations of Zoos and Aquariums to bring them back eventually. There is currently no timeline for when this might happen, she said. Meerkats have recently been born at zoos in Miami, Tucson, Ariz., and Chattanooga, Tenn.