Nepenthes are tropical pitcher plants native to parts of South East Asia, India, Madagascar and Australia. Most are vines, but some remain compact in habit. The name "Monkey Cups" comes from monkeys occasionally drinking the fluid in the pitchers.

The pitcher is actually a swelling of the mid-vein in the leaf. Insects are attracted to this because of nectar secretions and coloration. The slippery rim (peristome) and inner walls of the pitcher encourage insects to fall into the digestive fluid at the bottom of the trap. Nutrients are absorbed from this "soup."