The diet consists of coconuts, other nuts, fruits, and flowers. Litters of U. caudimaculatus have been recorded in New Guinea during November and December and may contain one to three young. The young remain with the mother until they are at least half-grown. U. anak is often hunted for food by the highland natives of New Guinea. With its formidable incisors, it is even able to open cans of food.
Population density varies greatly, and home range appears to be large.
Individuals are solitary and probably territorial. Males become highly aggressive during the breeding season, which begins in October-November with the onset of the summer rains. The gestation period is 36 days, and litters usually contain two or three young.