A baby hippopotamus who was just 5 days old died at the world famous San Diego Zoo this week. The baby weighed an estimated 40-45 lbs. (18-20 kg.) when it was born on March 29. At this point, zoo officials don’t know why or how the baby died. The baby hippos mother, Funani, had given birth to five calves so she was an experienced mother who was very attentive to her little ones. In fact, she was so protective of this baby that zoo keepers couldn’t get close enough to know whether it was a male or female.  In general, hippos are very protective of their babies.

Here’s a video of the baby with Funani.

Here’s another video of Funani teaching another one of her calves, Adhama, to swim.

Unlike the pigmy hippo, the river hippopotomus is not yet on the endangered species list, although population is dwindling since their tusks are in high demand.