Monday, January 31, 2011

Coyotes Are Omnivores

Rib bones still attached to the steer carcass with their surface shredded
By the three-week mark of finding the steer carcass at the Dipper Ranch, the skeletal frame is becoming exposed.  All the major bones are still attached yet something is scraping their surface.  I assume this is from gnawing or scratching by the coyotes since they are frequently caught by the wildlife cameras at the carcass, and their teeth and claws are more capable of shredding hard surfaces than the beaks of the other common visitors - ravens and vultures.

Day 20 - bones exposed on the steer carcass but limbs still attached
I've seen coyotes break apart and haul off pieces of deer carcasses much faster than this. Last year, I watched a coyote run through the "John Deere" meadow toting an entire deer ribcage in its mouth.  For now, the loosely connected steer carcass is still heavy and its skin too thick to easily tear apart, so the coyotes resort to gnawing it in place.

Raccoon Canine skull and jaw found in Bone Yard -
Probably a coyote but possibly a domestic dog.
The largest tooth is the canine tooth.
Carnivore: an animal that eats meat, usually by capturing live prey for consumption.  The Carnivora order of mammals have strong canine teeth to hold and tear flesh.

Carnivore scat at Mallard Pond packed with hair
Representatives of the Carnivora order in the Santa Cruz Mountains are:  coyote, gray fox, eastern red fox (introduced), grizzly bear (extirpated*), black bear (extirpated?), ringtail, raccoon, sea otter, seals, sea lions, striped skunk, western spotted skunk, long-tailed weasel, badger, mountain lion, and bobcat.  Coyotes represent the largest, native meat-eating dogs in these mountains.

Coyote hunting at grassland/brushland edge near the Dipper gate
Coyotes' most frequent prey are rabbits and rodents.  You may have seen a coyote pouncing in a grassy meadow and not even realized its playful gesture was the successful pinning of a vole because it swiftly swallowed the small animal whole.  They may capture and consume fawns, or sick, disabled and sometimes healthy adult deer.  They usually hunt alone, but bonded pairs and sometimes small packs hunt together as a unit.  Coyotes also capture small livestock such as chicken, sheep or calves, and will kill domestic cats and dogs.

Snake scales in a scat.
I used to think these were bits of plastic bags
 until I spotted the tip of a snake's tail in a scat
(center of this photo; click photo to enlarge).
Omnivore:  an animal that eats both plants and animals.  Coyotes are widespread in many different types of habitats and remarkably versatile to adapting to their environment and seasonal offerings.  In addition to meat, they commonly eat grass, fruit, berries, insects, snakes, and garbage.

On Day 8, I found this bright orange pellet near the steer carcass
and didn't know what it was.
Later, I pondered about orange berries and realized
two types were currently ripe:
madrone (shown above) and toyon.
When I smashed toyon berries (left),
they had hard black seeds
but the mystery pellet did not.
Smashed madrone berries have white pits,
similar to those in the pellet.
Mystery solved - probably a scat from
an omnivorous coyote.
The local coyotes seem especially fond of fruit, however, so are gray foxes.  I find it difficult to tell if a small scat consisting of a loose plop of seeds and skin, is from a fox or a coyote.

"I am king of the carcass."
Day 16
Scavenger:  an animal that feeds on dead material such as a carcass killed by another animal, sickness, injury, or starvation; also an animal that feeds on garbage and roadkill. Vultures are full-time scavengers, raccoons are commonly recognized as eating garbage and whatever they can get into, but even large carnivores like bears, coyotes, wolves and mountain lions will scavenge on carrion they did not kill.  It's important to remember that just because an animal is feeding on a carcass, that doesn't mean it was the predator that originally brought down the prey.

Vultures and ravens picking the carcass on Day 16.
I've been watching the interactions of scavengers at the steer carcass.  At Yellowstone National Park, Adolph Murie noted, "[T]he raven watches the coyote and the coyote watches the raven.  If one has found a source of food, he is sure to be joined sooner or later by the other."  At carrion, Murie watched coyotes and ravens ignore and harass each other. Coyotes heeded the cawing and flight of ravens as a warning of the approach of larger, competing scavengers.  Ravens watched and then stole from coyote caches.

Loose tufts of black hair scattered around the carcass on Day 12
as if the coyotes were scratching at the leathery cow hide
to break into new sections of meat.
In conclusion, coyotes are in the Carnivora order, put their canines to good use as meat-eaters, but they are also omnivores and opportunistic scavengers.  At the Dipper Ranch steer carcass, coyotes appear to be a key disassembler, tearing into the tough skin so that flesh is more available to other scavengers - the vultures and ravens.

Sneaking a persimmon out of the backyard.
See Also:

Mammals of the San Francisco Bay Region, William D. and Elizabeth Berry, University of California Press.

California MammalsVol. I-III. D.C. Zeiner, W.F.Laudenslayer, Jr., K.E. Mayer, and M. White, eds. 1988-1990. California Department of Fish and Game, Sacramento, California. 

Ecology of the Coyote in the Yellowstone, Adolph Murie, Fauna of the National Parks of the United States, Fauna Series No.4, 1940.

*Note:  Extinct means that all individuals of that species are gone forever.  Extirpated means that no individuals of that species occur in the area under discussion, but individuals may survive at other locations.


  1. Wow. Great post. And aren't you clever re: finding and crushing red/orange berries to see which was in the pellet. Nice! And, yes, thank you for sharing with folks that just because animal A is eating it, doesn't mean animal A killed it. A very important point.

    I just saw coyotes yesterday, and someone else posted pics of them yesterday--maybe something is in the air?

  2. Love that you figured out the orange pellet. This post is chock full of information! Thank you.

  3. The CA Mammals reference above says coyotes mate January through March (only one time per year as compared to domestic dogs) and pups are born about 2 months later. Maybe that is why we are seeing so many roaming coyotes right now.

  4. I believe the skull is from a raccoon.

  5. Declan: I just found a similar skull on the Dipper Ranch and a friend found another on the coast. With your comment and checking my new book Animal Skulls: A Guide to North American Species by Mark Elbroch, I agree that is a raccoon skull. Never realized those striped guys had such serious canines. Thanks.


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