Scientists have long suspected that big brains come with an evolutionary price — but now they've published the first experimental evidence to support that suspicion, based on their efforts to breed ...

Male guppies may sexually harass females of another fish species to prevent them from reproducing, researchers suggest. They believe the guppies – which have invaded Mexican rivers and lakes – are ...

It’s not uncommon in the animal world for males to harass females and force them to mate with them, even if the females are not interested. But a new study has revealed female guppy fish learn to ...