Rio, a 17-year-old Andean bear, has given birth to a cub at the Phoenix Zoo.
Rio and her cub are doing well, zoo officials said. This is the fourth cub for Rio, but for unknown reasons, all three in the past did not live more than seven days, the zoo said.
Rio and Billie Jean, an Andean bear at the National Zoo in Washington D.C., are the only Andean bears in North American zoos who have successfully reproduced since Billie Jean's birth six years ago. Billie Jean has had two sets of twins - one set in 2010 and another set born December 2012, just three weeks before Rio's cub was born.
Rio and her cub are in a maternity den where the family can bond in a quieter environment.
Zoo staff has been monitoring them through an audio baby monitor. It could even be several more weeks or months before zoo staff sees the cub.
This particular species has a high mortality rate, with first-year mortality at 41 percent for males and 44 percent for females.
The cub was sired by Rizarro, a 23-year-old Andean bear who came to the Phoenix Zoo in 2011 from the Pittsburg Zoo.
Andean bears are a small, arboreal, largely vegetarian bear from the Andes Mountains in South America. They are the only species of bear native to South America and are also called spectacled bears due to the white markings on their faces which make them look as if they are wearing glasses.