Twirly,

I am really curious about the biological fact that male coyotes kill any other breeding coyote. Drive him out of the territory, yes (perhaps) but I know of no evidence that suggests this commonly results in death. I also do not know of any evidence that males search out dens to kill coyote pups. There seems to be a dearth of information about these biological facts. In fact there seems to be considerable cooperation among coyotes at times to raise litters of pups. The following is the report of one study:

"Pack associates are either the grown pups from previous litters or are unrelated coyotes which were accepted into the pack by the mated pair (Bekoff & Wells 1980). If coyote density is high and emigration rates are low than a larger percentage of pack associates will be related to the mated pair (Andelt 1985). These additional members aid in obtaining resources, defending resources, and raising pups within the pack. In addition, pack associates increase the pack�s access to larger ungulate prey because there are more individuals to coordinate better hunting strategies (Geffen et al. 1996). Although the aid pack associates contribute to the pack may be beneficial, they are not critical for the mated pair�s pups to survive. This is demonstrated by mated pairs that successfully raise their pups without the aid of pack associates. The relationship between pack associates and the mated pair is an example of alloparenting. The pack associates receive more benefits than the mated pair or pups gain from them. First, they gain the protection of the pack. This is important to their survival because transient living, their other option besides being a part of the pack, has been shown to have much higher mortality rates. Secondly, the pack associate has a chance of inheriting the territory if one of the parents is sick or is killed and they are able to secure the alpha position. The third benefit is the valuable experience they gain by helping to raise the mated pair�s pups which will help them raise their own pups in the future (Bekoff & Wells 1980; Geffen et al. 1996; Kamler & Gipson 2000; Gese 2001). Since the parents receive little to no necessary aid from the pack associates, their helping behavior is considered to be selfish cooperation."

It coyote on coyote predation were such a big factor in coyote population dynamics I would think it would be reported commonly in studies of the social behaviour of these interesting animals.

Soooo, how about a reference or two or three from recognized researchers.

Cheers
Drac