A male Wild Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) has been filmed spontaneously ejaculating. It is apparently the first reported and filmed instance of this awkward yet fascinating event, a situation that is not unfamiliar to many adolescent male homo sapiens (the spontaneous ejaculation, not the filming hopefully).

[ Morisaka et. al. @plosone]

From the abstract:

Spontaneous ejaculation, which is defined as the release of seminal fluids without apparent sexual stimulation, has been documented in boreoeutherian mammals. Here we report spontaneous ejaculation in a wild Indo-Pacific bottlenose dolphin (Tursiops aduncus), and present a video of this rare behavior. This is the first report of spontaneous ejaculation by an aquatic mammal, and the first video of this behavior in animals to be published in a scientific journal.

Video at figshare.

[Some interesting observations at dolphin researcher justingregg's blog]