Within, and perhaps outside of, these general boundaries the range of coyotes appears to be expanding due primarily to their high reproductive potential, great dispersal ability, and opportunistic food habits (Vaughan, 1983). Coyote expansion has also been facilitated by the elimination of large competitors such as gray wolves (Canis lupus), with whom they usually compete unsuccessfully (Gier, 1975; Carbyn, 1982) and avoid (Fuller and Keith, 1981). Furthermore, coyotes show a marked ability to compensate for increased human exploitation (Knowlton, 1972; Sterling et al., 1983). They are able to exist and reproduce successfully in extremely diverse habitats ranging from sea level to 2000-3000 m, including deserts, open grasslands, broken and dense forests, and large cities such as Los Angeles, California (Howell, 1982; Wirtz et al., 1982). As Gier (1975) stressed, neither altitude, latitude, nor vegetation restricts their survival. The family Canidae, to which coyotes and 36 other species belong, is 1 of 7 polytypic families in the order Carnivora. Other members of this diverse order include the ursids, procyonids, mustelids, viverrids,

Urination and defaecation patterns of free-ranging coyotes (Canis latrans) were studied in the Grand Teton National Park, Jackson, Wyoming, for two years. The vast majority of urinations by adult males and females were involved in 'marking,' and differentiating between 'marking' and 'elimination' may not be necessary. Our results may be summarized as follows: 1) Raised-leg urinations (RLU) performed by males were most frequently used in marking. (2) Females marked throughout the year using the squat (SQU) posture. (3) Snow tracking and reading snow sign resulted in a gross underestimate of the relative frequency of SQU's and a large overestimate in the relative frequency of defaecations (DEF) when compared to results obtained by direct observation. (4) There was sexual dimorphism for the contexts in which marking occurred. Overall, marking by males was associated with courtship and mating, with travelling, and with aggression. Marking by females was associated with the acquisition and possession of food and with the denning season. (5) Marking rates per coyote increased in groups larger than two animals. (6) RLU marking rates were greatest in areas of high intrusion when compared to denning areas and areas in which non-group me hers infrequently trespassed. SQU marking rates were highest in denning areas and high-intrusion areas. We suggest that scent odours are important in orienting individuals in space but do not represent in and of themselves barriers to movement.

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Predatory behavior of coyotes (Canis latrans) was studied between 1977 and 1980 in the Grand Teton National Park, Jackson, Wyoming. Major prey were voles (Microtus spp.), Uinta ground squirrels (Spermophilus armatus), pocket gophers (Thomomys talpoides), and grasshoppers (Locustidae). Coyotes typically rushed and ran down squirrels; when hunting mice, coyotes pounced and stabbed at them with their forepaws. Sequence structure was similar, though sequences directed to squirrels were significantly more variable. When juvenile coyotes hunted mice, sequences were similar to those performed by adults that hunted mice. Adults and juveniles were about equally successful. The size of prey last eaten influenced the interval until the next search was initiated; the larger the prey, the longer the interval. However, the time interval since the last capture and the outcome (capture or failure) of the next predatory attempt were not correlated. Durations of search, orient, and stalk were longer in short (< 10 em) grass than in tall grass; stalk, orient, and total durations also were more variable in short grass. Coyotes that hunted in short grass were more successful. Durations of all acts were shorter and coyotes were more successful in snow less than 10 cm deep than in deeper snow. Mean orient and total durations were more variable in deep snow. Height of ground-cover apparently affected coyote movements and the way in which cues from prey were perceived. Local wind conditions did not affect capture success. Coyotes were least successful when they hunted mice and more successful when they hunted squirrels. More time was spent searching and stalking squirrels.