Duicón Dust Bathing

Jack P. Hailman

Dust bathing is a form of self-grooming that is common in birds and rids the bather of ectoparasites such as mites and lice. In this clip, a fire-eyed diucón (Xolmis pyrope) engages in a bout of dust bathing, preens its feathers, and ultimately scratches its head by lifting its leg over the wing (indirectly). Bird species can be divided into those that scratch their head indirectly, and those that do so directly, by extending the leg under the wing. While it was once argued that the method of scratching employed by birds mapped onto their underlying phylogeny, many exceptions exist, and some species change the method employed in scratching their head over the course of development. Still, the mapping of behavioral traits onto phylogenetic relationships can provide important insights into the evolution of behavior.

FURTHER READING: Lee A. Dugatkin, Principles of Animal Behavior, 3rd ed. (New York: W. W. Norton, 2013), chap. 2, “The Evolution of Behavior.” M.M. Nice and W.E. Schantz, “Headscratching movements in birds,” Auk 76 (1959), pp. 339–342.

Naked Mole Rats

Frank R. Castelli; P.W. Sherman Lab, Cornell University

Naked mole rats (Heterocephalus glaber) are eusocial mammals, exhibiting reproductive division of labor, overlap of generations, and cooperative care of young. This advanced form of sociality is thought to be a product of the same factors that promoted the evolution of cooperative breeding in invertebrates: (1) ecological constraints on dispersal and independent reproduction favoring group living, and (2) aspects of kinship and underlying reproductive biology that favored extensive cooperation within those groups.

FURTHER READING: Lee A. Dugatkin, Principles of Animal Behavior, 3rd ed. (New York: Norton, 2013), Chap. 2, “The Evolution of Behavior”; Chap. 9, “Kinship”; Chap. 10, “Cooperation.” E. A. Lacey & P. W. Sherman, Cooperative breeding in naked mole-rats: implications for vertebrate and invertebrate sociality, in N. G. Solomon & J. A. French, (Eds.), Cooperative Breeding in Mammals. (Cambridge, UK: Cambridge University Press, 1996), pp. 267–301.