Oregon Zoo investigators will perform a necropsy on Nicole, the Amur tiger who died Monday, to determine what happened. The 15-year-old big cat suffered an apparent seizure, and vets were unable to revive her. She and her brother Mikhail have been at the Zoo since 2000. Nicole’s keeper told KGW that Nicole was quite affectionate and will be missed. Amur tigers have a lifespan of about 14 years.

PRP