The helmeted hornbill (Rhinoplax vigil) is a very large bird in the hornbill family. It is found on the Malay Peninsula, Sumatra and Borneo. The casque (helmetlike structure on the head) accounts for some 11% of its 3 kg weight. Unlike any other hornbill, the casque is almost solid, and is used in head-to-head combat among males. It is a belief among the Punan Bah that a large helmeted hornbill guards the river between life and death.
It has mostly blackish plumage, except that the belly and legs are white and the tail is white with a black band near the tip of each feather. The tail is long and the two central tail feathers are much longer than the others, giving the bird a total length greater than that of any other hornbill species. The body length is 110–120 cm (43–47 in), not counting the tail feathers, which boost the length a further 50 cm (20 in). Males average 3.1 kg (6.8 lb) in weight and females about 2.7 kg (6.0 lb). Although sometimes considered the largest Asian hornbill, they weigh a bit less than the great hornbill (and considerably less than the African ground hornbills).
This species has a bare, wrinkled throat patch, pale blue to greenish in females and red in males. The casque goes from the base of the bill halfway to the tip, where it ends abruptly. It and the bill are yellow; the red secretion of the preen gland covers the sides and top of the casque and the base of the bill, but often leaves the front end of the casque and the distal half of the bill yellow. Unlike other hornbills, the helmeted hornbill’s casque is solid, and the skull including the casque and bill may constitute 10 percent of the bird’s weight.
This bird eats mostly fruit, especially figs. It may also use the casque as a weighted tool to dig into rotten wood and loose bark in search of insects and similar prey. Unlike many fruit-eating hornbills, it is sedentary, and pairs maintain a territory. Males fight over territory on the wing, ramming each other with their casques.