St. Louis (AP) Five rare tiger cubs have been born at the Saint Louis Zoo.
The Zoo says the critically endangered Amur tigers were born April 28th and are being kept in a den that's off display.
The zoo says first-time mother, Kalista, is busy nursing and caring for her babies.
The normal litter size for a tiger is two or three cubs. The five in St. Louis weigh four and a-half to seven pounds each.
The species used to be called Siberian tigers. They are at risk because of habitat loss, human encroachment and poaching.