The plant is known to occasionally trap vertebrates and even small mammals, with drowned rats having been observed in the pitcher-shaped traps.[8] It is one of only two Nepenthes species documented as having caught mammalian prey in the wild, the other being N. rafflesiana. N. rajah is also known to occasionally trap small vertebrates such as frogs, lizards and even birds, although these cases probably involve sick animals and certainly do not represent the norm. Insects, and particularly ants, comprise the staple prey in both aerial and terrestrial pitchers.