Little is known about the reproductive behavior in colugos. It is also found in some adult eutherian mammals, such as treeshrews, colugos, and rodents. Enamel wrinkling is also seen in some Philippine colugos. The living colugos lack such a strong postmetacristid. Its teeth already included the comb-like structure distinctive to modern colugos. The two species of colugos make up the order Dermoptera. In contrast to the colugos, the size and shape of the tines are more uniform. In colugos, the toothcomb has a completely different structure. The herbivorous colugos in the genus "Cynocephalus" may also use their toothcomb for food procurement. Colugos are unskilled climbers; they lack opposable thumbs and are not especially strong. Colugos are arboreal gliding mammals found in Southeast Asia. As a result, colugos were once considered to be close relatives of bats. Of all the gliding mammals, colugos have the most perfected adaptation for flight. Colugos are a small group of Southeast Asian gliding mammals closely related to the primates. Colugos are shy, nocturnal, solitary animals found in the tropical forests of Southeast Asia.