(Reuters) - The Oregon Zoo said on Friday it was forced to euthanize a newborn lion cub after it had been grievously injured by its mother accidentally.
Zoo workers became worried about the four-day-old cub on Thursday night when they noticed it wasn't moving like its three siblings, the zoo said in a statement.
Caretakers entered the private den of the first-time mother, seven-year-old Kya, and saw a badly infected wound on the cub's rear thigh. The mother further opened the wound in attempts to clean the gash, the zoo said.
The cause of the injuries were a mystery until workers reviewed surveillance footage of the den, the zoo said. Workers say Kya accidentally bit into the cub's femoral vein and artery when she gripped the newborn in her jaws shortly after birth.
On Thursday night, caretakers determined the injuries were untreatable and euthanized the cub.
"We did everything we could, but there was no way to save the cub," said zoo deputy director Chris Pfefferkorn.
Kya gave birth to four cubs on Monday. The other siblings, two girls and a boy, appeared to be healthy, the zoo said.
(Reporting by Curtis Skinner in San Francisco; Editing by Mark Potter)