Brookfield Zoo mourns dead dolphin

September 4, 2011 10:00:00 PM PDT
Nea, a 4-year-old dolphin at the Brookfield Zoo, died unexpectedly Monday afternoon.

Shortly before the 1 p.m. dolphin show, the marine mammal staff heard a loud pop.

They noticed that the Atlantic bottlenose dolphin appeared to be injured. She could not be revived.

It appears Nea died from a skull fracture suffered after by accidentally colliding with another dolphin.