CHICAGO (WBBM NEWSRADIO) -- The cause of a fall that resulted in the euthanization of Isis, Brookfield Zoo's last African lion remains a mystery.
According to Brookfield Zoo, 14-year-old Isis was found Monday laying on the floor of the moat in her outdoor habitat. Although not witnessed, it appears that Isis fell and was injured. Despite the immediate and intensive treatment provided by the veterinary staff, Isis sustained significant injuries and the decision was made to humanely euthanize her on Tuesday.
“The safety and well-being of the animals in our care is our utmost priority. Although it is unclear what caused her fall, we are reviewing all aspects of this tragic occurrence," said Bill Zeigler, senior vice president of animal programs on Tuesday.
WBBM Newsradio's Rachel Pierson followed up with the zoo on Thursday.
"We don't know exactly what happened," said Bill Zeigler, Senior Vice President of Animal Programs.
Zeigler said the moat has been part of the exhibit since the 1930's.
Zeigler said she had seizures Monday night and staff made the decision to euthanize her Tuesday.
"Zenda was something that was planned, so staff were able to prepare for it," Zeigler said.
Both Isis and Zenda arrived at Brookfield Zoo in May 2008. They could often be seen grooming one another and sleeping together.
"Our national zoo association has a number of programs called Species Survival Plans. And those Species Survival Plans take all the animals, like lions, that are in our North America collections, they're analyzed genetically and we analyze the population demographically, and then we make management decisions based upon building a sustaining population and maintaining as much genetic diversity," Zeigler said
The male lions are expected to arrive this spring.