Most of the world’s bats eat insects, and in areas with cold winters, that is all they eat. Many tropical bats eat fruit and nectar, and a few are carnivores that eat other animals, including rats and mice, small birds, frogs, lizards, or even fish. Only three out of more than 1,000 species drink blood.

Most experienced bat scientists can guess what a bat eats by looking closely at its adaptations. Each species of bat is adapted for the food it eats. Some bats specialize in eating just one or a few kinds of food, but others are generalists who eat various foods. Special adaptations, such as wings, feet, eyes, nose structure, and mouth structure, allow bats to find and eat certain kinds of food with little or no competition from other species. This is very successful as long as their unique food source is abundant, but such specialization is risky because the kinds of prey, fruit, flowers a bat eats might die out, leaving the bat to starve. Animals that eat various foods can switch types if one disappears, but they cannot compete well with specialized animals for any one food.