Rotational swimming preferences in mosquitofish: evidence for brain lateralization?

Rotational preferences of mosquitofish (Gambusia holbrooki) were investigated in circular tanks with a group of females or a group of predators located at the centre, or during spontaneous swimming in absence of any particular target. Mosquitofish swam preferentially clockwise in presence of the predators, whilst no significant preferences appeared with the females or during spontaneous swimming. Similar rotational biases have been reported previously only for rodents and marine mammals: the present findings suggest that even teleost fish may possess lateralized brains.