Drumbeak

Drumbeaks (genus Tympanirostris) are large beak-monkeys that dwell in the understory of the Payalan rainforest. Their most notable feature is their alarm call, made by flicking the hard backs of their ears against their elaborate beaks. The call’s resemblance to sounds made by percussion instruments is the origin of the name “drumbeak.”

Drumbeaks are among the many treetop animals cleaned by comb beetles at designated “cleaning stations”— the beetle’s comb-like mandibles strain out ticks and other harmful parasites, which they eat.

Evolution
Beak-monkeys are divided into two families: Kallidae (the limp-tailed beak monkeys) and Rhynchocebidae (the prehensile-tailed beak monkeys.) As evidenced by their long, hanging tails, drumbeaks are members of Kallidae, along with their close relative, the fruit-scooper.

External ears are a characteristic unique to drumbeaks and absent in all other beak-monkeys; structures similar to the fruit-scooper’s warning frills may have given rise to drumbeak ears.

Habitat
Drumbeaks generally keep to the lower levels of the rainforest, inhabiting the understory, and only rarely venturing onto the forest floor. They can sometimes be seen in the canopies depending on what types of fruit are currently blooming.

Diet
The drumbeak diet is about 80% fruits and nuts, and they have an important role in the jungle as seed-dispersers, since they tend to swallow fruit whole. They are opportunistically omnivorous and will eat insects and small animals on occasion.

Behavior
Drumbeak’s signature alarm calls are used to warn other animals of incoming predators such as swinging lizards or darangos. They can flee through the treetops with suprising speed for their bulk.

In addition to alarm calls, drumbeaks will “tap” their crests repeatedly to court mates and let others know their position in the forest. These calls usually have slow and mellow rhythms compared to their quick and urgent-sounding alarm calls. During courtship, a male and female will perform a sort of call-and-response song, slowly moving towards each other as the ritual progresses.

More than other beak-monkeys, drumbeaks actively seek out comb beetles and can most often be seen around cleaning stations. A comb beetle cleaning a drumbeak will always start from the end of the tail upwards— the reason for this behavior is unknown.