nature.net
February 2005
Howls and Growls
By Robert Anderson
In the first chapter of his Origin of Species, Charles Darwin argued that if you wanted tangible evidence for evolution, you need look no further than the family pet. “Artificial selection” among domesticated animals, he noted, had resulted in extraordinary variations in a relatively short time, and “natural selection,” Darwin explained, would work in much the same way.
To get some sense of how much variation exists among those of the canine persuasion today, visit the Web site of the American Kennel Club. The site lists entries for the 158 pure breeds recognized by the club (there are hundreds more). The Web site of the Westminster Kennel Club is, of course, the best place to find information about the club’s dog show—the premier event of its kind—which takes place in New York City in February.
If you want to explore the natural history of the domestic dog, a good place to start is the Web site of the Natural History Museum of Los Angeles County, at the online version of a recent exhibition titled “Dogs: Wolf, Myth, Hero & Friend.” Click first on “Evolution and Diversity,” which outlines the history and effects of both natural and artificial selection. Next click on “Form and Function,” from the vertical menu at the left, where you'll find brief accounts of the three senses that make dogs so exceptionally useful to people: vision, hearing, and smell.
Dogs are also contributing to the study of genetically transmitted disease in humans. This past summer the National Institutes of Health announced the first sequencing of a canine genome (see their News Advisory). The advisory notes that, because of the long history of selective breeding, many dog genomes carry information about diseases that afflict both dogs and people. Hence canine genetic sequences will prove useful for research on, among other things, cancer and autoimmune disorders.
Genetic studies have also helped emphasize that the apparent variety among dog breeds is mainly skin deep: every domestic dog is “cousin” to the wolf. At Canid Genetics, Robert K. Wayne has summarized some of the studies, and presents them with links to the related scientific papers. Wayne notes that in 1993 the American Society of Mammalogists and the Smithsonian Institution reclassified all domestic dogs as Canis lupus familiaris, a subspecies of the gray wolf.
So what about wolf evolution? On the home page of the Natural Worlds Web site, click first on “World of the Wolf,” which will take you to the topic page. Click on “Wolf History—The Fossil Record” to find a page of images linked to information about both extinct and extant wolf species.
More on the genus Canis is available at The Searching Wolf. Scroll down the home page to see an impressive list of links to sites on all things “wolf” (near the bottom, you'll even find a list of wolf sites specifically for kids). I particularly enjoyed the audio files of wolf vocalizing, which you can access by clicking on “Sounds,” in the blue menu box at the left. Launch the sound clips hyperlink, and try playing “Wolf Chorus Howling” to find out how your own domesticated wolf may react to the call of the wild.
Robert Anderson is a freelance science writer living in Los Angeles.
Copyright © Natural History Magazine, Inc., 2005