Three African blackfooted penguins mysteriously die at the Aquarium.

Zuri, Betty and Tranya are gone.

Their passing last weekend was sudden and unexpected, the Monterey Bay Aquarium announced today. Nobody knows what killed the three African blackfooted penguins.

Zuri and Betty died unexpectedly on Friday, according to the press release. The aviculturists, who know each individual in the exhibit, looked for penguins acting strange and isolated four of them. One of them, Tranya, died Saturday. The other three were moved back to the exhibit.

Dr. Mike Murray, the aquarium’s director of veterinary services, found no obvious cause of death in the post-mortem exams. Aquarium officials hope lab tests will eventually provide more clues.

Information from a number of laboratories will hopefully shed more light on the cause of death, but may take a few weeks to be completed. African blackfooted penguins are native to southern Africa and endangered.

The Aquarium's announcement includes the following short obituaries. RIP, penguins.

Zuri was hatched Nov. 10, 2002 at the Maryland Zoo. She arrived at the aquarium in 2006 and was paired with Pringle. The mated pair are the biological parents of Tola, a chick that hatched at the aquarium in 2011.

Betty hatched Nov. 13, 2008, also at the Maryland Zoo, and she and her sibling, Sabie, arrived at the aquarium in 2009. She was paired with Seekoei.

Tranya has been at the aquarium since 2005. He hatched Nov. 11, 1998 and came to Monterey from the Aquarium of Americas in New Orleans, along with his sibling Walvis. Tranya was paired with Molopo.