Answer: Birds

Although humans have developed quite an appetite for spicy food and consume peppers of all shapes by the ton, most mammals don’t care for the spicy burn of a hot pepper. In fact, evolutionary pressure on ancient pepper plants is exactly how we ended up with the peppery burn in the first place.

Pepper plants in the chili pepper family Capsicum adapted over time to produce a substance, capsaicin, that binds with pain receptors found in mammalian mouth and sinus cavities. Conveniently for the pepper plants, however, birds have few to no equivalent pain receptors in their mouths. As such, birds are a near perfect pepper seed propagation vehicle: they happily eat the pepper and its seeds, the seeds pass through their digestive tract undisturbed (whereas most mammals would crush/grind the seed during consumption), and they are deposited in nutrient rich bird droppings far from the point where they were eaten.

While seducing birds might have helped the chili pepper in the millenniums before humans came along, nothing gave them a boost like the human appetite for spicy food. There is evidence that the first chili peppers were domesticated approximately 6,000 years ago in Mexico and today many varieties of chili peppers are cultivated around the world (including varieties, for the thrill seekers, with capsaicin concentrations so high they can blister your skin).