Do Carnivorous Plants Eat Their Prey?

The ominous-looking Venus flytrap is one of the most famous carnivorous plants, and its snapping traps have fascinated many a curious child (or adult). But the Venus flytrap is just one member of a remarkable group. There are more than 600 carnivorous plant species, and the ability to catch and digest prey has evolved independently at least six times among flowering plants.

Despite their fearsome reputation, carnivorous plants do not “eat” insects and other prey as a source of energy. Like nearly all other plants, they are photosynthetic and use sunlight to manufacture sugars from carbon dioxide and water. Rather, they trap and digest insects and other small animals to obtain nitrogen and other nutrients that their roots do not frequently encounter in the poor soils where they typically grow. This adaptation allows them to exploit habitats such as bogs and wetlands that are challenging to other plants.

Different species have evolved a remarkable array of traps. Pitcher plants lure prey in passive pitfall traps filled with digestive fluids. Sundews and butterworts ensnare insects with adhesive leaves, while Venus flytraps and aquatic bladderworts use rapid “snap traps” to capture their victims. Most carnivorous plants attract and digest insects and other invertebrates, but some large pitcher plants have been known to digest frogs, rodents, and other vertebrates. A few also utilize leaf litter, and at least one pitcher plant uses animal feces as a source of nutrients.

Many carnivorous plants occupy highly specialized ecological niches and are limited to narrow geographic areas, making them especially vulnerable to habitat loss and overcollection. As a result, numerous species are considered threatened or endangered.