Can a parasitic infection change your personality? It can if you're a mallard duckling. These birds typically avoid unfamiliar objects and prefer
items that are green and blue. But when researchers injected Anas platyrhynchos ducklings at 4, 9, or 14 weeks old with red blood cells from sheep to simulate a parasitic infection, the birds—as adults—explored new items in their environment and approached small orange toys, a color they typically avoid because they seem to associate it with toxic food. Reporting online today in the Proceedings of the Royal Society B, the researchers hypothesize that these so-called personality changes may help adults explore a larger area and find more food. And this in turn may help them make up for the energy they've lost fighting the infection.