Wish I were a Catfish Swimmin’ in the Deep Blue Sea

Popular Science Magazine at the Dr.’s office:

Researchers also showed female mosquitofish videos of males with digitally enhanced genitals.

They found the females were drawn to the enhanced males rather than those with average sized genitals.

Scientists said the slowness of the well-endowed fish was caused by greater drag in the water, which reduced their ability to dodge predators with swimming bursts.

“This swimming burst is very important in avoiding predation, and males possessing relatively large gonopodia might experience reduced burst-swimming speed owing to the enhanced drag generated by the large genitalia,” they report.

Dr Rob Brooks, an expert on animal evolution and sexual selection from the University of NSW, said the research illustrated the opposing forces of evolution.

Without an evolutionary downside to having large genitalia, the male mosquitofish would simply end up with impracticably massive sex organs, Dr Brooks said.