Gender Bending Fish


A ma’am or a sir, a him or a her…maybe BOTH,  when attempting to score a mate. Those crazy cuttlefish are at it again with their amazing talent to morph.

New research finds that these clever mollusks use their color-changing abilities in creative ways: by pretending to be the other gender.

Well, half-pretending, that is.

When a male cuttlefish is wooing a lady, he often “cheats” by painting typical female patterns on one side of his body, while the other side (the one facing the female)  shows off typical male patterns. This gender-bending disguise fools rival males into thinking they’re seeing just a couple of ladies hanging out. That means more of an opportunity for the cheater cuttlefish to mate.

Culum Brown, a biologist at Macquarie University in Australia and his colleagues first noticed the cuttlefish’s “two-face” disguise in their laboratory, where they have a semi-natural enclosure for the mollusks. The scientists were conducting a study on anti-predator behavior when a group of Sepia plangon, or mourning cuttlefish, began courting. The researchers noticed that the males sometimes displayed a strange, split-down-the-middle coloration. On the side facing the female, they’d be getting their groove on, showing pulsating stripes to woo said lady. On the side facing a rival male, they’d show mottled camouflage (boredom, perhaps?), a typical female look.

The wily cuttlefish doesn’t always display this mating pattern. The behavior occurred only in groups where there were two males and one female, the researchers found. Extra females might have disrupted the male’s concentration or simply made it hard for him to orient his disguise in the right direction.

The other thought is that fish brawls may ensue when there are more males present. A less dominant fish might never get to mate if a fight ensues.


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