What extra quality do animals that work out how to exploit new food sources have? If you're a guppy, it seems to help if you're small, hungry and female (Anim. Behav. 57, 331-340; 1999).

Credit: CORBIS/DORLING KINDERSLEY

Kevin Laland and Simon Reader set up lab populations of the guppy Poecilia reticulata (below) consisting of males and females and hungry and well-fed fish. The fish were then put in a maze with food at the end of it. In three-quarters of the trials, a female was the first to discover the novel food source. Two-thirds of the time, it was a hungry fish that solved the problem. In a separate experiment the authors found that smaller fish were faster problem-solvers. There is some evidence that new behaviours can spread by imitation.

These results show that, rather than innovators being inherently creative, a fish's circumstances can drive it to experiment. Hungry fish are more active, better motivated to find food, and more likely to take risks than their better-fed counterparts. Small fish might do better to discover new food than fight with bigger fish for existing food sources.

Why, then, should females be smarter? Laland and Reader speculate that this is a consequence of motherhood. Guppies give birth to live young, so females, which are almost permanently pregnant, need extra food to nurture their brood. Males are probably better employed seeking out new mates than new food sources, so we might expect to see more innovative behaviour in this area of activity — something that could apply across the animal kingdom, as it is common for females to invest more in their offspring than males.

But it seems that innovators are born, as well as made. Fish that were ‘past innovators’ cracked new problems significantly quicker than ‘past non-innovators’. So — starving artists take note — although perspiration helps, it's best to have a spark of inspiration too.