Factors Affecting Body Size in Sympatric Ontario Canis

Body sizes and feeding habits of coyotes, Canis latrans, and wolves, C. lupus, in southeastern Ontario were examined between 1959-1969 and 1983-1984. Coyotes increased in mean body weight and length whereas wolves decreased in mean body length. The decrease in body length of wolves was correlated with an increase in the use of smaller, more abundant prey. It appears that body size of wolves and coyotes in Ontario has been selected for by the size and abundance of prey and is not the result of a coevolutionary response between two competing carnivores.