|Coyote (Canis latrans)|
Wolf (Canis lupus)|
These hybrids, known as coywolves, are produced in the northeastern U.S. and eastern Canada, wherever wolves and coyotes come into contact. They are fertile in both sexes and apparently better adapted to urban environments than are either coyotes or wolves, so that the hybrid population is currently expanding and moving into large cities such as Toronto and New York.
Wayne and Vila (2003) speculated that, “female wolves and male coyotes are more closely matched in size, and thus may also be more likely to mate.” However, Lehman et al. (1991) found coyote mtDNA in most of the ostensible wolves in the hybrid zone, but found no wolf mtDNA in any of the coyotes, which indicates a strong directionality to the cross, that is, that male wolves usually mate with coyote bitches (although the reciprocal cross has occurred in captivity). So it appears that Wayne and Vila's assumption was mistaken. Hybrids tend to backcross to wolves, not coyotes.
Paradiso and Nowak (1972, p. 1) note that the red wolf, Canis rufus, is “highly variable in all characters,” which is consistent with a recent hybrid origin, and that it is in general intermediate between latrans and lupus with respect to the measurements of its characters. Moreover, Wayne and Jenks (1991) and Reich et al. (1999) offer convincing genetic evidence that rufus is in fact derived from this cross, and all historical specimens of rufus seem to be hybrids (Nowak 2002; Roy et al. 1994a, 1996). Nevertheless, the IUCN describes C. rufus as a critically endangered species.
The following is a list of reported 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).
Note: Theil (2006) describes the behavioral interaction of wolves and coyotes in the wild.
Additional references: Boyd et al. 2001; Ferrell et al. 1980; French and Dusi 1979; Gipson et al. 1974; Kolenosky 1971; Lawrence and Bossert 1967, 1969; Lehman et al. 1991; Mengel 1971; Paradiso and Nowak 1971, 1972; Phillips et al. 2003; Pilgrim et al. 1998; Roy et al. 1994a, 1994b, 1996; Sears et al. 2003; Silver and Silver 1969; Stanfield 1970 (p. 35); Thiel 2006; Wayne 1996; Wayne and Vila 2003; Schmitz and Kolenosky 1985a,1985b; Sears et al. 2003; Wayne et al. 1991; Young and Goldman 1944; Young and Jackson 1951 (p. 124). Internet Citations: RUFUS.
Human Origins: Are we hybrids?
On the Origins of New Forms of Life
Cat-rabbit Hybrids: Fact or fiction?
Georges Cuvier: A Biography
Prothero: A Rebuttal
Branches of Biology