| Summary: | This article was published in the Spring 2013 issue of the Journal of Undergraduate Research Domestic dogs, Canis lupus (variety familiaris), show extremes of morphological variation in comparison to their ancestor, the wolf (Canis lupus), with some breeds being much smaller than a typical wolf (males 40-60 kg, females 30- 45kg), while other breeds are much larger. A major trend observed to be a result of the process of domestication is paedomorphosis, or retention of juvenile traits into adulthood. Dogs express paedomorphic traits to different degrees, ranging from phenotypes that resemble wolves to extreme forms such as toy dogs, with short muzzles and legs. These traits can be both morphological to behavioral in nature. Such traits must interact because morphology is used to express behavior. One key example of this is the use of both ear and tail orientation to signal status in interactions among dogs. By observing dyadic encounters, I measured the extent of paedomorphic reduction of the ability to use signaling behaviors, specifically those involving the ears and tails. I did not find a correlation between overall paedomorphosis and frequency of signaling, but did find significant interactions between signal frequency and the degree of dissimilarity of the tail of individual breeds from a wolf tail. Despite this interaction, I found that signaling was consistent across breed types and sizes. This indicates that signaling is highly conserved and evolutionarily important, even across a large range of phenotypes. When tail signaling is reduced, it is often associated with a highly variant tail, especially those artificially shortened by human action.
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