A suburban Philadelphia zoo says four of its animals have died of unrelated, but natural causes in recent months.
Philly.com reports the Elmwood Park Zoo in Norristown made the announcement Monday.
The zoo says Matilda the elk was euthanized after she developed a neurological disorder and had trouble walking. Officials say the 15-year-old's necropsy revealed Alzheimer's type II astrocytes in the animal's brain.
In May, a 24-year-old Saki monkey named Lace began to deteriorate after an upper respiratory infection. Officials euthanized Lace in June after the monkey stopped responding to treatment.
A Leicester Longwool sheep, named Diva, also died after suffering a seizure.
Nox, a 15-year-old gray wolf, was found to have a bleeding mass in her liver and spleen and was also euthanized.