|A coydog (Coyote × German Shepherd) Image: Wikimedia, Lyta79|
Coyotes and dogs hybridize extensively in North America. The hybrids are partially fertile in both sexes. Hybridization of this type has been known since at least the 1880s (Seton 1929, p. 401; Shufeldt 1887). Hybrids are known as "coydogs."
The cross is reversible, but it usually involves a male dog because, although any male dog can fertilize a female coyote in heat, to fertilize a bitch in heat, a male coyote must be in rut. Mengel and others (Gier 1957, pp. 46-47; Kennelly and Roberts 1969; Silver and Silver 1969, pp. 31-32) have reported that coy-dogs breed earlier (December) than pure coyotes (February). Coyote testes usually begin to regress in March and by June no spermatozoa are present. Gipson et al. (1975) say male hybrids are seasonal breeders like the coyote, but their cycle begins two months earlier than a coyote’s and may peak after male coyotes. Length of gestation in F₁ hybrids is intermediate (62-63 days, vs. 58-62 in dog and 60-65 in coyote).
Mengel says an F₂ generation was more varied than in the F₁ (mongrel C. familiaris female × C. latrans male) and composed of “doglike to somewhat coyote like animals. Behavior varied, but all of the animals were intermediate, with some coyote-like traits, including howling…their small number [mean = 2.25 pups; range 1 to 3] in relation to the possible number, suggests some decrease in fecundity but might also have resulted from crowding or other suboptimal conditions inducing prenatal mortality. There was a rather high incidence of dental anomaly.”
Wild hybrids are widespread in North America and relatively common. For example, a single hunter killed 25 in Kansas between 1945 and 1951 (Gier 1957, p. 45). Regarding a population, thamnos, in Minnesota (treated as a race of C. latrans) and a highly variable hybrid population in New England, Lawrence and Bossert (1969, p. 8) say that
Hybrids howl like coyotes but also bark like dogs. Shufeldt (1887) says F₁ hybrids that he observed “run and trot like the coyote; and when off at a distance they have a way of standing sidewise as motionless as a statue and regarding you; while at such times they keep their two fore-limbs together, as well as the hinder ones. Such a position is very commonly assumed by the prairie-wolf [i.e., the coyote], and may be said to be a direct lateral view of the animal, with its face looking towards you.” Mengel (p. 324) mentions an F₁ male with asymmetric teeth (C though M2 much longer on left side).
The following is a list of dog crosses discussed on this site. Some of these crosses are much better documented than others (as indicated by the reliability arrow). Moreover, some are extremely disparate, and so must be taken with a large grain of salt, but all have been reported at least once.
By the same author: Handbook of Avian Hybrids of the World, Oxford University Press (2006).
References: Bee and Hall 1951; Bekoff 1977; Carson 1962; Cook 1952; Dice 1942; Gier 1957; Gipson et al. 1974, 1975; Hall 1943a; Hilton 1978; Kennelly and Roberts 1969; Kolenosky 1971; Lawrence and Bossert 1969; McCarley 1959; Mahan 1977; Mahan and Gipson 1978; Mengel 1971†; Murie 1936; Richens and Hugie 1974; Riley and McBride 1975; Seton 1929; Shufeldt 1887; Silver and Silver 1969; Young and Jackson 1951 (pp. 121-124).