Biologists have long believed that elephants and sea cows, despite their obvious modern differences, share a common ancestor.

ECONOMIST: The elephant and the mermaid

It is estimated that more than 80 sea cows died in collisions last year - a 20% increase on 1998.

BBC: Manatee

As land repeatedly surfaced and receded, the remains of marine creatures got mixed up with those of terrestrials, forming one big Ice Age graveyard: sea cows, prehistoric sharks, spike-tailed armadillos the size of refrigerators.

NEWYORKER: Bones of Contention