Sirenia are herbivorous mammals of coastal waters. They have arms, which are modified into paddles, but no legs, are fat, and have highly modified skulls with greatly reduced dentition. Their nipples are under their arms (see the picture of a pair of manatees).
... capable of it.
According to EADS, the maximum speed possible without reheat is Mach 1.5 (although this drops to Mach 1.2 with an air-to-air weapons load). ...