Explained: Another beluga whale dies at Chicago aquarium after rescue mission from Canada park

A third beluga, Osiris, died at Chicago's Shedd Aquarium after being rescued this summer from Marineland in Canada.

Necropsy

An examination of an animal's body after death to determine cause of death.

NOAA Fisheries

A U.S. federal agency that oversees marine species protection and regulation, including reporting requirements for whale deaths.

Cook Inlet beluga

A population of beluga whales native to Alaska's Cook Inlet, classified as endangered.