Coyote (Canis latrans)
Social Organization
Image courtesy of National Park Service
Dominance Hierarchy
Coyotes have well developed dominance hierarchies within the pack which
is adhered to once the hierarchy is established through ordered fights
between competing coyotes. The hierarchy may change if a member is forced
to leave the pack or if
the
pack accepts
a new
member (Bekoff & Wells; Gompper 2002). In addition, if an alpha
male dies or gets replaced, the alpha position is always filled from
within the pack
(Gese 2001).
Packs & Mated
Pairs
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Coyotes which live in northern and western areas of their range display more
developed and complex social systems than coyotes found in the southern and
eastern areas of their range (Chamberlain et al. 2000). All coyotes travel
and live together either in groups of three or more individuals called packs,
as mated pairs, or as solitary individuals, called transients (Andelt 1985;
Bekoff & Wells 1980; Chamberlain et al. 2000). The basic unit of a coyote
pack is the mated pair. The mated pair is always comprised of the alpha male
and alpha female, which are typically the only individuals to breed in the
pack. To form a pack the mated pair is accompanied by pack associates who
can be genetically related or unrelated individuals (Bekoff & Wells).
Coyotes may live in packs because they are able to better defend resources
such as food caches or carrion (Bekoff & Wells 1980). This beneficial
adaptation would allow individuals in that pack to access more resources and
therefore give the alpha male’s pups a better chance of surviving to
maturity. This also may have evolved in areas with high competition pressures
from the wolf before it virtually disappeared from the coyote’s habitat.
In general, more coyotes live in packs, approximately 70%, than coyotes that
live as mated pairs, approximately 17%. The other 13% accounts for transient
individuals. Packs make up a large percentage of the population because pups
will stay with their parents up to one year after birth. If resources are
very scarce pups may stay for a longer time period with their parents becoming
pack associates before venturing off to find their own territory (Andelt 1985).
There are many benefits that coyotes receive by living in a pack. These benefits
include a better and more efficient defense of the pack’s resources,
and the pack is able to locate food sources more easily with additional members.
In addition, pack associates take some of the strain off the breeding female
from searching for food to defending the territory while allowing her to conserve
energy and have healthier, longer living pups although this isn't necessary
for the pups (Bekoff & Wells 1980). The social organization of the coyote
is based on food availability and social intolerance within the group structure.
During times of food shortage the pack will force subordinate individuals
out of the group that then become transient (Gese et al. 1989).
Transients
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The transient status is generally
not a desirable way of living for the coyote. This can be seen in the demographics
of the transient populations. Transient individuals are either yearlings,
indicating they recently left the protection of their birth pack, are disabled,
diseased, or elderly. Its believe that transients acquire their low status
because they are for some reason unable to compete within the hierarchy of
the pack and are subsequently ejected from pack life (Gese et al. 1988). Transient
individuals also have a much higher mortality rate than coyotes living in
either pairs or packs. This is because they don’t have access to easily
accessible resources and they gain protection from other individuals as do
coyotes living in a mated pair or in a pack (Andelt 1985; Atwood & Weeks;
Kamler & Gipson 2000). Although transient individuals have the lowest
social status they are not necessarily doomed to the transient lifestyle.
Transients that are healthy year old coyotes or individuals that are recovering
from a disease may be accepted into a pack if the mated pair approves (Kamler
& Gipson 2000). Although transient coyotes may live the undesirable life,
there are some benefits to being solitary. The main benefit is access to rodents
which are the transient coyote’s major food source. Rodents are a resource
which is hard to defend by a large pack of coyotes or mated packs and is difficult
to share amongst many individuals. Transient coyotes are able to gain access
to the rodents and don’t have to share their food with other individuals
as a in the pack's situation (Bekoff & Wells 1980).
Pack Associates
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.
Hunting
Behaviors
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Coordinated group hunting among coyote packs is rare because of their
ability to survive on small mammals such as gophers (Bekoff & Wells 1980).
However, when coyotes do attack large prey they form a coordinated hunting
group and target the weak or old individuals (Bekoff & Wells 1980). In
addition, coyote packs have been observed to collaborate in order to protect
and defend a valuable resource from intruders (Bekoff & Wells 1980).
Due to the fact that coyotes depend so heavily on small mammals for much
of their food source they have developed an efficient solitary hunting method.
The coyote’s first step is to locate its prey. This may involve searching
for the prey or searching for fresh signs of prey. Once the general vicinity
of their target prey is determined, the coyote proceeds to thoroughly search
and establish its precise location. Next the coyote will stalk its prey,
moving as close as possible without being noticed. The coyote will charge
its prey to take it by surprise if it can’t get closer while remaining
inconspicuous. If this step is successful then the coyote will pounce on
its prey with the front paws to pin it to the ground. The coyote kills by
biting its prey in the head and neck, occasionally followed by violent shaking
(Bekoff & Wells 1980). Although coyotes have a highly developed solitary
hunting method they only make a successful kills 10% to 50% of the time (Bekoff & Wells
1980).
Some coyotes exhibit special short term hunting relationships with badgers.
Coyotes and badgers team up together to hunt for small mammals that live
underground such as ground squirrels. Both the coyote and the badger
will visually scan the surrounding area but the badger seems to rely
on the
coyote’s
acute visual sight to guide them to the prey. If a group of ground squirrels
are found that are above ground both the coyote and badger will rush
the group to make kills. If the ground squirrels are able to escape and
hide
underground the badger takes over and start digging for the prey. This
is an advantageous partnership for both animals because they benefit
from each
other’s strengths. The coyote has highly acute eyesight and badgers
are extremely efficient diggers. The short term relationship these two
species have for hunting persists because the morphological adaptations
of the
coyote and the badger are complementary to hunting small mammals such
as ground
squirrels. Current research suggests this relationship is mutualistic
because benefits received from the relationship for both species are
more beneficial
than the costs of maintaining the relationship (Minta et al. 1992).
Howling
Behaviors
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Coyotes have at least three different types of vocalizations used in
various situations. The first call is lone howling done by a single
coyote. Lone
howling lasts a long period of time and has a higher pitch compared to
the other types of calls. This call is thought to be a type of communication
by lost
or separated members of a pack. The second type of vocalization is group
howling. This type of call is characterized by several coyotes each giving
a lone howl at the same time. The third type of vocalization is the group-yip
howl. The group-yip howl is identified by patterned high intensity yips
and howls performed by multiple coyotes in a group. Both the group
howling and
group-yip howling appear to serve the same functions. One function is to
advertise the location of the group’s territory and the second is
to coordinate group hunting strategies (Bender et al. 1996; Gese
2001;
Gompper 2002). By announcing the general area of a coyote pack’s
territory they can reduce the risk of encountering another pack of coyotes
which may
result in a violent and costly fight (Bender et al. 1996).