Seals behaving badly
Seals are raping penguins and scientists don't know why.
This recent phenomenon has been observed among young Antarctic fur seals on Marion Island in the South Atlantic. They are targeting king penguins.
In a newly published research paper, a South African research team - Ryan Reisinger, William Haddah, Tristan Scott, Marthán Bester and Nico de Bruyn - documented three incidents of seals on the island sexually assaulting penguins.
There have been other recorded incidents over the last 30 years.
"In human terms, you would call it rape," said Reisinger.
"The penguins react as they would to a predator trying to kill them; they initially fight for their lives but the seals are much larger and stronger, so they easily overpower the penguins."
The birds are injured in these encounters. In one incident, a seal attempted to copulate with a penguin, then ate it.
The researchers are not sure what is driving this behaviour.
It was at first thought to be part of the seals' normal predatory behaviour towards the penguins becoming misdirected.
The highly unusual behaviour might be learnt, "but we don't know what the reward may be for learning this behaviour", said Reisinger.
Another theory is that competition for females has forced some younger males to turn to penguins.
"It's a little perplexing, shocking and, strangely, a bit embarrassing to see I guess, but there is definitely nothing funny about it," De Bruyn said.