A rare black rhino calf was born to first-time parents at the St Louis, Missouri zoo, officials said.
Weighing in at just over 55 kilos (120 pounds), "the little male is nursing well and being cared for by his mother," the zoo said in a press release Tuesday.
Black rhinos are a critically endangered species after being poached nearly to extinction between 1970 and 1992.
Intensive anti-poaching efforts have seen the wild population in Africa rise from about 2,300 in 1993 to 4,240 today, according to the International Rhino Foundation.
The Saint Louis Zoo is among 37 institutions in North America working to breed rhinos in captivity.
A name has not yet been chosen for the calf, the first to be born at the zoo in 20 years.
Mother Kati Rain and father Ajabu, both six, arrived in St. Louis in 2007 after being transferred from zoos in Kansas and California.
The mother and calf -- who was born January 14 -- are bonding in their off-display barn and will move into their outdoor habitat when the weather turns warmer.
Explore further: Scientists reveal global patterns of specialized feeding in insect herbivores