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Wolverine

Order: CARNIVORA
Family: MUSTELIDAE
Genus: GULO
Species: GULO

The wolverine is the largest member of the weasel family Mustelidae and, though formerly classified as its own New World species, luscus, it is usually classed as the same species found in Eurasia, gulo. Wolverines are known by several colloquial names. The genus and species name “gulo” means “The Glutton” referring to its reputation as a ferocious slayer and consumer of all it encounters. “Skunk-bear” alludes to the wolverines resembling small bears, skunk like body striping, and habit of marking food sources with musk and/or urine. The Cree called them “Ommeethatsees” meaning “one who likes to steal” relating the wolverines=92 reputation for raiding traps/trap lines, human food caches, and cabins. As with many colloquialisms, there is some basis in reality and some degree of exaggeration in these names.

The wolverine is a stout, thick bodied, short-legged weasel weighing 20 to 60 pounds and measuring from 30 to 45 inches long including its 7 to 9 inch, bushy tail. As with most members of the weasel family, there is significant sexual dimorphism in body size with males averaging about 10% longer of body and 30% heavier. This sexual dimorphism decreases with increasing latitude. Wolverines are described as dark brown with prominent, broad, yellowish buff stripes from shoulder to rump on both sides of the body sometimes extending onto the tail. They also often have white to yellow headbands, collars, and/or socks that can aid in the identification of individuals. The wolverine generally walks heel to toe in a plantigrade fashion with 5 toes usually, but not always, registering in the 3-4 inch wide by 4-5 inch long track. Common gaits include an alternating direct register at a walk, 3 and 4 print lopes, and, less often, the mustelid 2×2, bounding pattern.

Wolverines cover an average of about 15 miles per day (except females with kits) searching for food and marking their territories primarily at night. Territories range from about 50 -500 sq. miles; males generally having notably larger territories than females and often overlapping the territories of a few to several females but not of other males. Communication and territory marking is accomplished primarily by urination and secondarily by musk from anal, plantar (back feet), and abdominal glands. Low population densities are thought to be the norm but recent studies indicate that “The Glutton” is probably not as solitary as once thought. Wolverines prefer high mountain wilderness often including the alpine zone, taiga, or tundra and coastal regions in the more northern latitudes of their range. They are circumpolar existing in the northern latitudes of both the Eurasian and North American continents. On the N. American continent, they are believed to range in parts of CO, CA, OR, WA, ID, MT, WY, AK, and most of the provinces of Canada. There is evidence that they once roamed the montane zones of AZ and NM, pre-European settlement of this continent. Their distribution seems to be directly associated with the presence of large mammals as carrion food resource (i.e. ungulates or sea mammals.)

The “skunk-bear” is especially carniverous with ungulate and sea mammal carrion being of critical importance in their diet. They will actively predate small mammals like snowshoe hares, birds like ptarmigan, and, opportunistically, large mammals that are injured or bogged down in the snow. When available, wolverines will also eat significant amounts of berries and insect larvae. These big weasels are infamous for raiding traps for the bait (=3Dcarrion), human food caches, and cabins and are known to haunt avalanche chutes for carrion that may be found buried in the snow. They have a great nose for detecting food buried deep in the snow, powerful musculature and claws well suited for digging through snow and ice, and powerful jaws capable of crushing large ungulate femurs (as moose) and tearing frozen meat. Wolverines are also known for caching food and scent marking food caches.

Lynx

Order: CARNIVORA
Family: FELIDAE
Genus: FELIS
Species: lynx (canadensis)

The Canadian Lynx is one of three wild cats that are known by the common name Lynx. The others include the Spanish Lynx, which is listed as an endangered species, and the Eurasian or Northern Lynx. The Canadian Lynx is a boreal cat which historically inhabited coniferous forests of the northeastern United States, the Great Lakes, the Rocky Mountains, and the Cascade Mountains. Each of these areas are now separated from each other by habitat unsuitable for lynx populations. It’s current range overlaps and replaces the more common bobcat from the northern portion of western mountains and the Canadian border, continuing northward through out Canada and Alaska.

A full-grown lynx can weigh up to 40 pounds and measure 38-40 inches long, which is slightly smaller than a bobcat and males are slightly larger than females. They have a coat that has been described as buffy or gray colored with a few black hairs. During the summer their coat can appear to be more reddish or gray-brown. Underneath its face there is a whitish ruff with black streaks. Lynx are said to have a stooped appearance due to the fact that the cat’s hind legs are longer than the front. Similar to a bobcat, they have a “bobbed” or shorter tail but are identifiable by two striking differences. First, their characteristic ears, which have prominent tufts and secondly, the larger paws, which are twice as large as those found on a bobcat, and are covered with fur to keep it from sinking into deep snow. These enlarged feet make lynx highly adapted to hunting snowshoe hares in the deep snow. Prints are rarely clear and individual pads are difficult to discern due to the heavy fur that covers their paws. Drag marks may be observable from this fur as the paw is removed from a track and moved forward. Lynx become sexually active when 2-3 years old and give birth to young in May or June. They are nocturnal and are active all year.

Lynx feed primarily on snowshoe hares, named for their exaggerated, larger hind paws. Lynx populations are strongly associated with hare population levels, which fluctuate greatly in cycles that rise and fall approximately every 9-10 years. Lynx choose forested areas with high hare populations searching for prey. By hiding in these dense areas they are able to hide or stalk their prey. Hare will comprise most of their total diet which is supplemented by tree squirrel, mice, various bird species including grouse, and have also been known to feed on carrion. These forest carnivores are very good climbers and are known to ambush prey from trees. Like other members of the Felidae family, they will cache their prey and feed on it for several days.

 

Lynx habitat needs require a forest with tree communities of various ages and a mix of deciduous and coniferous patches. Also needed are dead and downed logs and windfalls, which provide cover for denning sites, escape from other predators, and protection from severe weather. Earlier successional forests provide suitable habitat for the main prey species the snowshoe hare. Lynx tend to avoid open areas and prefer dense cover and rocky areas commonly associated with wooded thickets. They are solitary animals and are active mostly at night, though in the winter they become more active during the day.

On March 21, 2000 the Canadian Lynx was listed as a threatened species under the endangered species act. According to the forest service a species is listed as threatened when it is likely to become endangered throughout all or a significant portion of it’s range. The majority of lynx populations inhabit land managed by the Federal Government. Within the contiguous United States, lynx populations occur at low densities, which are related to the limited availability of snowshoe hares. Lynx metapopulations in the US are part of a much lager core population of lynx in Canada. Low densities of lynx in the US are due to the natural patchyness of boreal habitat and possibly the compounding negative effects related to development and management decisions, which if harmful to snowshoe hare populations or the ability for lynx movement, will negatively effect lynx numbers.

Fisher

Order: CARNIVORA
Family: MUSTELIDAE
Genus: MARTES
Species: pennanti

The Fisher is a medium size member of the mustelid family often compared to the American Marten, a slightly smaller mustelid, due to many shared habits and characteristics. The “fisher-cat” is neither much of a fish catcher nor is it a member of the cat family though it does resemble a house cat in general body size and shape, but the fisher has shorter legs and a longer, wedge- shaped snout. The fur on a fisher is dark brown to black, as an animal ages the hair tips may become ‘frosted’, especially around the head and shoulders. They molt in the fall. Males generally have coarser hair coats, this makes the females more desirable to trappers. Their bodies measure 20 – 30 inches with an additional 13 – 17 inches of tail and weigh from 3 – 12 pounds. Males are usually significantly larger than the females. Tracks reveal 5 toes in a plantigrade foot averaging 3 in. wide by 4.5 in. long with thick fur on the soles of their feet in winter. The nails are at least partially retractable though not sheathed and the mustelid, 2×2 bounding gate is most common with fisher track patterns. (see tracking section for illustrations)

Fishers are considered to be quite carnivorous, favoring snowshoe hares as well as squirrels, carrion, mice, shrews, voles, birds, fruits like berries, and ferns. They are also famous for their ability to successfully hunt and kill porcupines. One of the very few other animals to prey on porcupines is a close cousin of the fisher, the wolverine. The fishers’ long, wedge-shaped snout is well suited for making vicious attacks to the porcupines face until mortal wounds cause the porcupine to succumb. In some forests, fishers have been reintroduced to try to control porcupine populations. This biological control method has been successful at least for short-term population reductions; it is currently unknown how well it works for long-term porcupine population control. They generally hunt by systematically searching for patches of abundant prey and then systematically searching those patches for prey to kill. Fishers will sometimes cache food items and find/make temporary den sites near large food items like a deer carcass.

The breeding season for fishers is in late March and April. Like most other mustelids, fishers experience delayed implantation of 10 – 11 months. The egg is fertilized at the time of mating, then the embryo stops developing and remains in a dormant state until the female is in good physical condition during late winter, the embryo then implants and develops. The actual gestation lasts approximately 30 days with parturition (birth) occurring in March and April. They typically breed again within 10 days of parturition. Females breed at one year and have their first litter of about 3 kits at age 2 years. Males are probably not sexually mature until age 2. Fishers are pretty solitary animals except during the breeding season when plantar glands on their hind feet increase secretions and a black, tarry substance of unknown origin signal their intent to mate.

Fisher natal and maternal dens are usually located high (+/- 50 ft.) in tree cavities which partially explains their overall preference for mature to old growth, late successional, forest habitats. Researchers have noted significant use of young to mature forests during the winter. They also require significant tracts of contiguous forest with a high degree (70%) of canopy cover and prefer conifer or mixed conifer and northern hardwood forest types. They are also disproportionately associated with riparian communities for less than well known reasons. Fisher distribution and survivability is negatively impacted by forest fragmentation, stand isolation, and deep, fluffy snow. In comparison, martens have very similar habitat requirements but they are much less inhibited by deep snow. This may be an important way in which these two species are segregated. There is a considerable span of home range size estimates from 1.5 to 25 sq. miles, probably averaging around 10 sq. miles. Once again, males tend to have much larger territories than females, which often overlap territories of more than one female but rarely that of another male. Fishers will commonly travel 2-3 miles each day and while they are arboreal to some degree, most hunting and traveling is on the ground. They mark their territories and communicate with urine and anal, cheek, abdominal, neck, flank, and plantar (feet) glands. Martes pennanti was formerly widely distributed across northern forests of N. America up to around 60 degrees N. latitude, south in the Appalachian Mountains to North Carolina, and throughout the Pacific Coast mountains. Current distribution is now well known but they have not returned to the southern Appalachians, and are considered spotty in the Pacific Coast mountains, especially in Washington and Oregon, and in the southern reaches of their former distribution in the Rockies. These medium size weasels are particularly susceptible to logging and trapping.

Marten

Order: Carnivora
Family: Mustelidae
Genus: Martes
Species: Americana

The American marten, or pine marten, is a medium-sized member of the weasel family (the mustelids). It is also known as the American sable, and is closely related to fishers, badgers and weasels. Martens were trapped widely in the 1800’s for it’s rich brown fur, and is still trapped in some states for its beautiful coat. In color, the fur is a rich, medium brown with a characteristic orange throat patch.

Pine martens are 21 to 26 inches in length, including the long, bushy tail and weigh 1.5 to 2.75 pounds. Males are 20 to 40% larger than females. Being carnivorous, they feed on primarily on voles, mice, red squirrels, with supplemental feeding on insects, birds, eggs, fruit and nuts. They may live for up to 17 years.

Tracks of the pine marten reveal five toes in a plantigrade foot averaging 1.5 to 2.5 inches in with by 3 to 4 inches in length. The straddle is 3 to 4.5 inches and the stride of a marten averages around 20 inches, with the 2 X 2 bounding pattern typical of the weasel family.

The breeding season for martens is in late March and April. Like most other mustelids, fishers experience delayed implantation of 10 – 11 months. The egg is fertilized at the time of mating, then the embryo stops developing and remains in a dormant state until the female is in good physical condition during late winter, the embryo then implants and develops. The actual gestation lasts approximately 27 days with parturition (birth) occurring in March and April. A typical litter has 2 to 4 kits, with one litter per year. They typically breed again within 10 days of parturition. Females breed at one year and have their first litter of about 3 kits at age 2 years. Males are probably not sexually mature until age 2. Martens are pretty solitary animals except during the breeding season when plantar glands on their hind feet increase secretions and a black, tarry substance of unknown origin signal their intent to mate.

Martens are similar in behavior to their larger cousin the fisher. Martens prefer late successional forests, with mature to old growth trees being especially important for natal and maternal den sites. Martens appear to like to make temporary dens and perches in mistletoe bundles known as ‘witches brooms’. They are distributed circumboreally, found through spruce-fir forests from northern New Mexico to the northern limit of trees in Alaska, and from the West Coast to the Newfoundland Islands, in mountain ranges with suitable habitat. Marten generally require a high canopy cover (up to 70%), although Wild Things researchers have documented marten presence in forests recovering from recent fires. This is due to the high numbers of mice and voles that feed on the rich vegetation that thrives after a burn.

The home range is probably half to one square mile, but ranging up to seven miles. Males have larger home ranges than females, with females often having overlapping territories, but rarely overlapping with males.

Martens are highly inquisitive, and are known for their habit of investigating anything new in their territories. Unfortunately, this makes martens very easy to trap. They are often encountered in the Yellowstone Ecosystem feeding on the carcass of a winter-killed elk or other ungulate.

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