“…the sea otter positioned itself dorsal to the [seal] pup’s smaller body while grasping it by the head and holding it underwater in a position typical of mating sea otters. As the sea otter thrust his pelvis, his penis was extruded and intromission was observed. At 105 min into the encounter, the sea otter released the pup, now dead, and began grooming.”
Also, and more recently, a rare golden lion tamarn monkey was eaten by otters in accident at British zoo.
I remember watching a sea otter catch seabirds off the northern coast of California. The otter would catch the birds and break the necks, or at least that is what I thought it was doing. It was pulling the heads off and then drinking from the bird’s body like a viking’s grog.