Curiosities: Why can birds eat hot peppers?

June 14, 2010

In the 1990s, scientists began to wonder why birds in the Southwest ate the hot-tasting fruits of a wild plant called the “bird pepper.” Rodents had not been seen to dine on the pepper’s fiery fruits. Scientists fed bird seed to two species of birds, and then fed the same food coated with capsaicin, the active “hot” chemical in peppers, and “they did not lose weight and were fine,” says Anna Pidgeon, an assistant professor of forest and wildlife ecology at UW–Madison. Birds may be able to eat peppers because they have so few taste buds: Chickens have just 24 taste buds, and pigeons have 37, Pidgeon says. Humans have close to 10,000 taste buds, and rodents and other mammals likely have a similar number, Pidgeon says. “We can’t be sure why birds don’t sense the hot taste, but they seem not to be affected by it. Still, there is plenty of evidence that birds discriminate among chemicals. Chickens will accept sucrose in water, but not saccharine. Although both have the same sweet taste, they have a different chemistry.”