The second finger of the nauger is remarkable, being about as long as the forearm. It is used for poking down burrows and winkling out the larvae of the wood beetles on which the arbrosaur feeds. A hooked claw at the end secures the catch. The skull of the nauger is perfectly adapted to its purpose of drilling into solid wood. The teeth grow only at the front of the jaw and are directed forward, each one lending support to the one before. Those at the very front bear the brunt of the pecking force. When they wear out or break, they are replaced by more teeth growing in from behind. The neck joint is very strong, protecting the back of the skull and the brain and giving support to the heavy neck muscles needed for the constant rapid pecking.
The Nauger, Picusaurus terebradens, is a partly quadrupedal, woodpecker-like arbrosaur from the deciduous and mixed woodlands of North America, in The New Dinosaurs: An Alternative Evolution. Predators include the treepounce.
In the deciduous forests of North America live a vast variety of different arbrosaurs, each one specifically adapted to a particular way of life. One of the most highly specialized is the nauger, with its wood-boring jaws and its long thin finger. It feeds almost exclusively on the grubs of wood-burrowing beetles that it hunts in the living wood of the trunks and branches. The strong hind legs and the stiff bristles on the tail give it a firm grasp on the tree while it listens for movement beneath the bark and drills into the wood after the larvae.
If there were no non-avian dinosaurs still living in the Cenozoic, it is possible that some of the ecological niches now occupied by tree-living arbrosaurs would have been occupied by birds. It seems entirely probable that a bird could have evolved to fill the niche of the pecking arbrosaur, with a strong bill taking the place of the powerful teeth, and possibly a specialized tongue doing the work of the long finger.