SAN DIEGO - A 5-day-old hippopotamus born at the San Diego Zoo was found dead on Thursday, zoo officials said.
Zoo staffers made the discovery during routine morning observations, zoo spokeswoman Christina Simmons said. The cause of death was unknown, she said.
On Wednesday, the zoo announced the birth and said the mother, Funani, had kept the calf so close that animal keepers could not determine if the baby was male or female. Simmons called her "an experienced mother and very attentive."
It was Funani's fifth calf, the zoo said. She last gave birth in 2011. The father is named Otis.
Hippopotamuses are a threatened species, facing both natural predators and man-made dangers such as poaching, according to the zoo.
With so many obstacles in the wild, mother hippos are known to be very protective of their newborns.