Determining whether predation has occurred, and by what species, requires knowledge and experience. Evidence must be gathered and evaluated with regard to predators in the area, time of day, season, types of wounds, and other factors. Sometimes, even experts are unable to confirm the cause of death. It may be necessary to rely on circumstantial information. For more information, refer to “Procedures for Evaluating Predation on Livestock and Wildlife.”
Damage to Structures
Coyotes are not known to damage structures.
Damage to Livestock and Pets
Predation by coyotes on livestock generally is more severe during spring and summer, when the diet of coyotes changes from fiber to largely protein. While coyotes frequently are blamed for losses of domestic animals, they often scavenge animals that perished by other means. The observation of droppings and tracks of coyotes near a carcass is insufficient to prove predation by coyotes.
Accurate identification of predation requires quick discovery of the deceased animal. The determination of predation becomes less certain as the carcass ages, or if the remains are few or scattered. The quantity of remains of the prey that is left after a kill varies widely, depending on how recently the kill was made, size of the animal killed, weather, and number and species of predators that fed on the animal.
To determine if coyotes are responsible for the kill, look for signs of struggle, such as scrapes or drag-marks on the ground, broken vegetation, or blood around the site of the kill. Look for the presence of subcutaneous (just under the skin) bleeding at the point of attack. Bites to a dead animal will not produce evidence of bleeding, but bites to a live animal will. If enough of the carcass remains, carefully skin the neck and head to observe punctures by teeth, and hemorrhage around the punctures. Coyotes typically attack sheep at the throat, but young or inexperienced coyotes may attack any part of the body. Coyotes usually kill calves by eating into the anus or abdominal area. Dogs generally do not kill sheep or calves for food and are relatively indiscriminate in how and what part of the animal they attack.
Sometimes it is difficult to differentiate between kills by dogs and coyotes without looking at other signs, such as size of tracks (Figure 3) and spacing and size of puncture wounds on the prey. The average stride of a coyote at a trot is 16 to 18 inches, which typically is longer than that of a dog of similar size and weight. Generally, dogs attack and rip the flanks, hind quarters, and head, and may chew the ears of their prey. Sheep sometimes remain alive but may be wounded severely. Punctures from talons of large birds of prey also may cause hemorrhage, but the location of the wounds usually is the top of the head, neck, or back.
Coyotes may kill several animals in a single episode, but often only feed on 1. Coyotes, foxes, mountain lions, and bobcats usually feed on a carcass at the flanks or behind the ribs and first consume the liver, heart, lungs, and other viscera. Bobcats and mountain lions often cover a carcass with debris after feeding on it. Bears generally prefer meat to viscera and often consume the udder from lactating ewes first. Eagles skin carcasses on larger animals and leave much of the skeleton intact. With smaller animals such as lambs, eagles may bite off and swallow the ribs. Feathers and droppings called “whitewash” usually are present where an eagle has fed.
Damage to Landscapes
Coyotes damage plots of watermelons (Figure 4). They also eat fallen and rotting fruit, and may bite irrigation lines.
Health and Safety Concerns
Coyotes typically are not considered a threat to humans, though several documented attacks have occurred, including one that resulted in the death of a human. Children are at the greatest risk. Researchers have created an ascending scale that may be useful in evaluating the likelihood of an attack by a coyote in some situations:
- An increase in numbers of coyotes on streets and in yards at night.
- An increase in numbers of coyotes approaching adults or taking pets at night.
- Early-morning and late-afternoon observance of coyotes on streets and in parks and yards.
- Observance of coyotes chasing or taking pets during the day.
- Coyotes attacking and taking pets on leash or in proximity of their owners.
- Coyotes chasing joggers, bicyclists, or other adults.
- Coyotes seen in and around play areas for children, school grounds, and parks during the day.
- Coyotes acting aggressively toward adults during mid-day.
Coyotes suffer from various diseases, including distemper, hepatitis, parvo virus, and demodectic and sarcoptic mange (caused by parasitic mites, Figure 5). Rabies and tularemia also occur and may be transmitted to other animals and humans. Coyotes harbor numerous parasites including mites, ticks, fleas, worms, and flukes.