Male cuttlefish cross dress to get to females

Male cuttlefish disguise themselves as females so they can get close to potential mates being guarded by rival males.

New research published today in the journal Nature says that males of the Giant Australian cuttlefish, Sepia apama, use their ability to instantaneously change colour to pose as females allowing them to access broody females being guarded by dominant male cuttlefish.

Roger Hanlon, a marine biologist at the famous Woods Hole Marine Biological Laboratory in Massachussets, and his co-authors describe in Nature how male competition for females is intense in S. apama, with as many as 11 males fighting to mate with a single female.

Hanlon says that rival males fight with each other for females and guard their mates closely from other males when they win. However, Hanlon found that other males were changing their colours so that they looked females so they could sneak in and mate with the female behind the back of the male.

In order to disguise itself, the male cuttlefish not only has to change its colour, it also has to hide some of its arms and alter the shape of the visible ones so they look more like those of a female\'s.

\"We\'re finding genetic proof that sexual mimicry leads to immediate fertilisation\", Hanlon told

For more details read the paper: Hanlon, RT., Naud, MJ., Shaw, PW and JN Havenhand (2005) - Behavioural ecology: Transient sexual mimicry leads to fertilization. Nature 433, 212 (20 January 2005); doi:10.1038/433212a