These animals and many others self-medicate, using plants and other surprising materials to improve not only their own health but also the health of their offspring.

A video of capuchin monkeys at the Edinburgh Zoo shows them rubbing onions and limes on their skin and into their fur as an antiseptic and insect repellent. Biologists have noticed that parasite-infected female monarch butterflies are more likely to lay their eggs on anti-parasitic milkweed, giving their offspring instant medication, while uninfected females show no preference. And urban birds who incorporate cigarette butts into their nests may be doing so because chemical properties in the smoked cigarettes may repel parasites, according to a 2012 study.While cigarette-butt wallpaper may not appeal to