Coyote (Canis latrans)
Background Information
Image courtesy of National Park Service
Physical Description
Coyotes resemble small wolves in their physical appearance, in fact Lewis
and Clark called the coyote “prairie wolf” when they encountered
them on their journey to the west (Gompper 2002). The coyote's coat color
can be a wide mixture of colors including white, gray, brown, and rust. These
colors may change over the course of an individual’s lifetime (Bekoff
& Wells). In addition, coyotes exhibit a slight degree of sexual dimorphism
between the sexes depending on their geographical location. Coyote males range
in size from 8 to 20 kilograms and females are slightly smaller (Bekoff &
Wells 1980). In general, male coyotes weigh approximately 12-18% more than
female coyotes (Bowen 1982). There is also difference in body size between
coyotes living in western states and coyotes living in eastern states. Coyotes
living in eastern states are slightly larger in size than western coyotes
(Gompper 2002).
Habitat & Distribution
Coyotes are currently found in Canada, North America and Central America occupying
almost every habitat imaginable (Bekoff & Wells 1980). Before wolves were
eliminated from the United States, coyotes only occupied the western U.S.
However, without the competition from wolves they have expanded their habitat
to include all of the U.S. except Hawaii (Gompper 2002). Packs tend to prefer
open grasslands which is advantageous for the pack’s hunting strategies.
Prairies which contain large coyote populations include many species of grasses
and shrubs which attract small mammals, one of the coyote's food sources.
The features of these prairies include scattered, patchy areas of juniper
woodlands (Gese et al. 1988). It is believed that coyotes adapted to prairie
life and their behavioral traits are optimized to this habitat (Bekoff &
Wells 1980). Transient coyotes, which are of lower social status in the coyote
population, are forced to use sub optimal habitats. They use the woodlands
and cultivated fields which the packs prefer not to use (Kamler & Gipson
2000). However, in some areas coyotes display the opposite trend and are generally
found at higher densities in well covered woodland areas rather than in open
prairie lands (Gese et al. 1989). In addition, coyotes tend to prefer habitats
with a high abundance of available mammalian prey and fruits (Gese et al.
1988; Chamberlain et al. 2000).
Food
Image courtesy of Wilderness Photography Expeditions
Coyotes are opportunistic omnivores which take advantage of a variety
of resources found in their environments (Chamberlain et al. 2000;
Bowyer et al. 1983). Their food sources include, but are not limited
to, small
rodents, rabbits, deer, elk, moose, antelope, cattle, hogs, skunk,
javelina, armadillo,
opossum, birds, crustaceans, insects, lizards, prickly pear cactus,
fruits, and grasses (Bekoff & Wells 1980; Andelt 1985; Rose & Polis
1998). Coyotes are active during both the day and night hours but
are much more
active at night, particularly times around dawn and dusk (Andelt 1985;
Bender et al. 1996). This also affects the types of prey coyotes
are able to eat
because some animals have very different daily activity patterns which
would prevent coyotes from hunting them. The type of food that coyotes
utilize
is also dependent on group or pack size. Transient coyotes generally
scavenge more than coyotes living in pairs or packs (Kamler & Gipson
2000). This is probably due to the fact that packs can organize hunting
strategies that a solitary
coyote can’t accomplish alone. Both mated pairs and packs hunt
large ungulates much more than transients. In addition, packs
have been observed to hunt ungulates
more than mated pairs (Gompper 2002).
The percentage of mammalian flesh in the coyote's diet varies depending
on the season. As the seasons change coyotes must constantly modify
their diets to fit the available resources for that time of
year (Bekoff & Wells).
For example, in the winter months mammals account for approximately
87% of the diet. This is due to the low availability of flora during
the cold winter months. In the summer months mammals account
for approximately 28% of the diet. Mammals
compose such a large portion of the
coyote winter
diet due to low availability of other food sources in the colder
months such as insects, lizards, and plants (Andelt
1985; Bowyer et al. 1983). Coyotes also differ in the manner they
obtain food between the cold and warm months. During the winter season
coyotes tend
to scavenge for carcasses of dead animals, such as ungulates, while
in the summer months coyotes tend to kill their prey, such as small
rodents (Bekoff & Wells
1980).
Studies have also shown that it takes at least two coyotes to kill an adult
deer. This eliminates deer as a potential food source for transients and some
mated pairs (Bekoff & Wells). In addition, during the winter months transients
and mated pairs rarely gain access to carrion. When a pack finds the carcass
of a dead animal it will intensely defend the desirable resource (Bekoff &
Wells). Carrion is a very valuable food source during the winter. This is
because tracking the scent and locating the carcass dosen’t involve
extensive energy expenditures from to stalking and killing living prey.
Predators
Image courtesy of National Park Service
Coyotes have very few natural predators. These predators include alligators,
wolves, mountain lions or cougars, and most detrimental to the coyote
populations, humans. The type of predator a coyote may have is
dependent on its
location, although human predators threaten
coyotes over their entire range
(Andelt 1985; Gese et al. 1989; Gompper 2002; Sacks & Neale
2001). Human related activities account for the majority of
recorded coyote
deaths each
year (Gese et al 1989). These human activities may include
hunting, poisoning, trapping, and automobile related fatalities.
In addition,
coyotes have
been major targets for sport-hunters in recent decades (Windberg
et al. 1997).
Other
information
Image courtesy of Michael H. Francis
Ranchers and farmers utilize the same habitats as coyotes and often
times experience the consequences of these two lifestyles colliding.
Livestock
herds are an abundant and easy food source for coyotes which
take advantage of this defenseless resource. In western states alone,
coyotes reportedly
kill approximately $27 million worth of livestock each year (Gompper
2002). In response, approximately 97,000 coyotes are killed annually
in an attempt
to lower the number of livestock deaths per year due to coyote
predation (Gompper 2002).
Before wolves were persecuted from much of the U.S., wolves and coyotes shared
the same habitats and were considered interference competitors. They were
interference competitors because both wolves and coyotes used the same habitats
and the same resources. However, the wolves, being more aggressive, would
prevent the coyotes from accessing those crucial resources. Wolves were more
aggressive and would limit coyote access to resources which in turn limited
their populations. Wolves were also known to purposefully target and kill
coyotes even if they were not intruding in a wolf territory. The wolves did
this simply because the coyotes represented competition. Without wolves present
to limit their populations, coyotes are able to take full advantage of the
available habitats and resources. Without limitations coyote populations have
dramatically increased and have since expanded to occupy all of North America.
The influence that wolves once had over coyotes can be seen in regions where
wolf recolonization projects have been successful. In these areas where the
wolf populations have started to increase, the coyote populations have begun
to decrease. Coyotes in these regions have also started to change their microhabitats
to avoid the wolf populations (Gompper 2002).