PLATE 81
BEARS
BLACK BEAR Ursus americanus 1.5–2.1m, 8–14cm, 47–409kg; 1.3–1.7m, 8–14cm, 39–236kg
Distinguished from other bears by smaller size, larger ears, pale muzzle, and a rounded back. Fur color varies geographically; most eastern animals are dark black; western populations can be brown, cinnamon, or blond. Some coastal populations in British Columbia and Alaska are creamy white (Kermode Bears) or bluish gray (Glacier Bears). Some animals have a white chest patch. Lips are prehensile. Males are larger. Often leaves its mark on trees when stripping bark to eat sap, climbing tree with claws, or rubbing and scratching to mark territory. In most areas the Black Bear hibernates through the winter in ground or tree dens; in the far south only pregnant females hibernate. Populations are increasing across most of their range, and this is the bear most likely encountered in North America, even roaming into densely populated suburban areas. Unlike other bears, they are basically shy, and retreat quickly, sometimes after a brief bluff. Omnivorous, it is an opportunistic predator in woodlands and swamps, and is the only bear in eastern forests.
BROWN BEAR Ursus arctos 1.0–2.8m, 6–21cm, 80–600kg
Impressive, powerful, large brownish bear with a massive head with a dished facial profile and a humped shoulder. Fur color variable and may be virtually any shade of brown. Head and shoulders are typically paler than the darker sides, belly, and legs. Front claws are extremely long. Ears are round and indistinct and tail is short. Variable in size with larger coastal and island (including Kodiak Bear) populations and smaller inland (Grizzly Bear) forms. Males are larger. Leaves marks on trees like Black Bears. Omnivore and predator. Breeding is in May–July, but implantation delayed until November, and gestation is 6–8 weeks while the female is hibernating. In January–March, 1–4 young are born growing rapidly from a birth weight of 500g to 15kg by 3 months of age. Maximum life span is 20–30 years in the wild. Threatened and declining through much of its range in North America and Europe. Seasonally abundant near salmon spawning streams. Solitary, except for females with cubs. Persists in remote forests, tundra, and open plains.
POLAR BEAR Ursus maritimus 2.3–2.6m, 7–12cm, 400–800kg; 1.9–2.1m, 7–12cm, 175–300kg
A very large, white bear of the Arctic. Longer neck and relatively smaller head than other bears. Fur may appear yellow in summer. Females first breed at age 5–6, and pregnant females may weigh up to 500kg. Breeding season is April–May but delayed implantation slows gestation until fall, and cubs are born in December. Neonates are tiny (600g) but grow quickly in the den, and emerge at 10–12kg in March or April. Cubs remain with their mother for 2.5 years, learning to hunt seals on the sea ice. Only pregnant females overwinter in dens; all others remain active. Ringed seals are the prey of choice, but they also take bearded seals, and occasional harp seals, hooded seals, walruses, belugas, narwhals, and even sea ducks. They are able to fast for up to 8 months if food is unavailable. Threatened by melting ice associated with global warming and airborne pollutants that accumulate in polar regions. Home ranges may exceed 300km2 in areas of receding ice. Pursues fish and seal prey in pack ice and coastal regions.
PLATE 82
PROCYONIDAE
FAMILY PROCYONIDAE-This group of medium-sized members of the order Carnivora are all omnivores or frugivores. They typically have long tails and are good climbers.
RINGTAIL Bassariscus astutus 62–81cm, 31–44cm, 870–1143g
Unique with slender build and long, bushy, striped tail. Face is gray, back is pale yellowish to tawny reddish in color and the underparts and feet are pale. Flat-edged tail has 14–16 stripes and a black tip. Males are slightly larger. Strictly nocturnal. Eats fruit, mice, and other small prey. Found from sea level to 1400m, and occasionally up to 2900m. Can tolerate some human presence, and sometimes found in small urban nature preserves. Use a variety of habitats with rocky outcroppings, canyons, or talus slopes including montane conifer forests, riparian areas, dry tropical habitats, chaparral, and deserts.
RACCOON Procyon lotor 63–95cm, 20–40cm; 60–91cm, 19–34cm, 4.0–15.8kg
Well known for its dark mask and ringed tail. Grizzled pelage varies from gray to blackish. In winter a yellowish or reddish tinge may develop on the nape of neck. Albino, dark brown, and cinnamon color phases are also known. Omnivore and semiaquatic forager, using their dexterous hands to find and catch small prey. Raccoons are probably the most omnivorous mammal in the world, and will eat whatever food items are most common in an area. They have learned how to exploit human foods in many areas, including agricultural crops and urban garbage. Typically solitary, urban raccoons have learned to tolerate each other where food is abundant and they can reach densities of 50–100 animals per km2. Nocturnal. Larger in north, where well-fed animals can reach 50% body fat. Common in every habitat with water sources.
WHITE-NOSED COATI Nasua narica 85–164cm, 25–38cm, 2.7–6.5kg
This tropical procyonid reaches the northern edge of its range at the US-Mexico border. Unique with a long mobile snout and a slender tail with incomplete dark rings. Males are about 20% larger than females. The Coati is an active diurnal forager, and may spend 90% of its waking hours hunting food. Eat a variety of invertebrates and fruit that they find by using their snouts to sniff under the leaf litter. Good climbers, but obtain most food on the ground. Females and young travel together in bands of up to 40 animals while males are typically solitary. In the United States they are typically found in riparian pinyon-oak-juniper habitats, but occasionally range into deserts and savannahs.
PLATE 83
AQUATIC MUSTELIDS
AMERICAN MINK Neovison vison 55–70cm, 19–22cm, 550–1250g; 47–60cm, 15–19cm, 550–1000g
Dark, semiaquatic weasel with a white chin patch. Back and belly rich brown; variable amount of white on chin and throat. Hind toes slightly webbed. The Sea Mink subspecies(N. v. macrodon) was larger and redder, with a strong scent. It used rocky sea shores along our North Atlantic coast until it was hunted and trapped to extinction by the 1860s; some consider it a full species. Solitary, except for females with young, and most active at dusk and dawn. Predator of aquatic birds, mammals, fish, and frogs. Breeding is in the spring and delayed implantation may extend gestation to an average of 51 days; 3–6 young are produced each year in a single litter, and weaned at 5–6 weeks. Dens are in the banks of forested or brushy streams, under tree roots, in hollow logs, or in abandoned muskrat houses. The American Mink is common, but rarely seen, near the shoreline of waterways and lakes.
NORTH AMERICAN RIVER OTTER Lontra canadensis 1.1m, 42–47cm, 7.7–9.4kg; 0.9–1.1m, 31–40cm, 4.5–13.6kg
The only river otter in North America. Back is brown; chin and throat are silvery. Tail is long, thick at the base, and gradually tapering. Mostly nocturnal, often seen at dusk or dawn. Scenting latrine areas on shore consist of matted-down vegetation and scraped-up earth, with defecations around the periphery. Eats fish and other aquatic prey. Dens are reworked from other animals’ burrows or natural shelters under logs, trees, rocks, thickets or along river banks. An underwater entrance leads to a nest chamber lined with plant material and hair. They mate in the water in late winter or early spring, and the active gestation period is about 2 months, but can last up to a year through delayed implantation. Lives in most types of unpolluted freshwater and coastal marine habitats, but rare or extirpated in many parts of the east and Mid-west.
SEA OTTER Enhydra lutris 1.3–1.4m, 36cm, 18.0–45.0kg; 1.1–1.4m, 27cm, 11.0–33.0kg
The only fully aquatic carnivore, and one of the smallest marine mammals, with plush fur, pawlike hands, and flipper-like feet. Tail is flattened dorso-ventrally. Noses of females are often scarred from aggressive males. Forages solitarily (females with their pups), but often rests and socializes in groups called “rafts” that are readily observable from shore. Rafts in south are small (fewer than 12) but hundreds of males may congregate in the north. Foraging dives last from a few seconds to 4 minu
tes, and prey items are brought to the surface to eat. Sea Otters typically float on their back and handle invertebrate prey on their belly, using rocks as tools to open hard invertebrates. Females breed at about 4 years and have a single young annually after a gestation period of about 6 months. Recovering from massive hunting at turn of century, still threatened. Lives in shallow coastal waters.
PLATE 84
BIG MUSTELIDS
AMERICAN MARTEN Martes americana 560–680cm, 20–23cm, 470–1250g; 50–60cm, 18–20cm, 280–850g
Identifiable with bushy tail, buff-orange throat patch, and sharp facial profile. Fur varies from light to dark brown. Legs are short and ears are small and rounded. Larger than American Mink and smaller than Fisher. Predominantly a predator of small mammals and birds, will also eat fruits and insects. Active day and night year-round, with peaks at dawn and dusk, but secretive and rarely seen. Maximum lifespan 15 years. Sensitive to trapping pressure and logging; recent natural expansions and managed reintroductions are helping Martens reclaim some of their historic range. Arboreal and terrestrial hunter of coniferous forests.
FISHER Martes pennanti 90–120cm, 37–41cm, 3.5–5.5kg; 75–95cm, 31–36cm, 2.0–2.5kg
Large, dark-colored, stocky weasel. Bigger and darker than American Marten. Face, neck and shoulders sometimes marked with hoary gold or silver-colored guard hairs. Deep brown coat lightens over summer, darkens in fall molt, and may appear reddish in spring. Throat and chest are marked with white or cream patches of varying size and shape. Females are smaller, with finer and glossier fur. Arboreal and terrestrial predator of small and medium-sized animals. Regularly preys on Porcupines with fast frontal attacks; also eats fruits and nuts. Increasing in the east, declining in the west. Hunts in a variety of forest types.
WOLVERINE Gulo gulo 94–107cm, 22–26cm, 11.3–16.2kg; 86–93cm, 21–25cm, 6.6–14.8kg
Largest member of the weasel family, with a pair of yellowish bands running from shoulder to rump. Has a large head and a short, stout neck. Typically holds tail and head low while walking with an arched back. Wide-ranging, solitary scavengers and predators of Caribou and smaller prey, such as ground squirrels, snowshoe hares, and ptarmigan. Mainly nocturnal, but occasionally out in the daytime. Breeding is in spring, summer, and fall, and delayed implantation results in 1–5 young born in February–April. Maximum lifespan is about 5 years in the wild. Dens are excavated in snow, under uprooted trees, or in rocky crevices. Lives at low densities in tundra and forested habitats.
AMERICAN BADGER Taxidea taxus 60–87cm, 10–15cm, 3.6–11.4kg; 52–79cm, 10–15cm, 3.6–11.4kg
Unique with short legs and black and white striped face. White stripe runs from nose to neck in most populations; stripe continues to base of tail in the southwestern animals. Long coarse fur is gray on the back and may be mixed with white, brown, buff, rust, or orange color. Young are pale buff-colored. An efficient digger with very large claws, its presence can be detected by frequent diggings and den entrances. Secretive and solitary, but fiercely defensive when attacked. Sleeps through most of winter, but becomes active on warmer days. Hunts ground squirrels and other small and medium-sized prey. Lives in grasslands, deserts, and open marshy areas.
PLATE 85
MUSTELA
LEAST WEASEL Mustela nivalis 180–205mm, 25–40mm, 40–55g; 165–180mm, 22–30mm, 30–50g
North America’s smallest carnivore; lacks a black tail tip. In summer, back varies from rusty brown to pale sandy tan; belly is white or yellowish. Northern populations have a pure white winter coat. Molting animals may appear spotted. Rarely seen, even though active day and night year-round. Well-developed senses of sight, smell, and hearing allow them to use postural, vocal, and olfactory communication. Preys on mice day and night; must eat its body weight in food each day. Slender body plan allows them to chase mice down burrows. Prefers marshes, grasslands, and other nonforested areas.
ERMINE Mustela erminea 219–343mm, 65–90mm, 67–116g; 190–292mm, 42–70mm, 25–80g
A short-tailed weasel with a dark tail tip and (typically) white on feet. Smaller than Long-tailed Weasel, with a relatively shorter tail (less than 44% head-body length). Males are 40–80% larger than females; animals can also be sexed by genital morphology. Back is brown in summer. Winter coat is white, with a black tail tip. Primarily a nocturnal hunter of mice, young rabbits, and other small prey. Breeds in summer, but delayed implantation results in 4–9 young born in spring, in a burrow or hollow log. Young reach adult size by about 6–7 weeks, and mothers teach the young to hunt by going out in family groups. Uses most habitats in range, the widest variety of all mustelids.
LONG-TAILED WEASEL Mustela frenata 330–420mm, 132–294mm, 160–450g; 280–350mm, 112–245mm, 80–250g
A long-tailed weasel with a dark tail tip. Larger than the Ermine, with a relatively longer tail (more than 44% head-body length). Variable amount of white on hind legs and feet. Northern populations molt to a white winter coat. Some populations in Florida and the southwest have white or yellow facial markings (leading to the name Bridled Weasel). Hunts small prey, especially mice and young rabbits. Dens are in dense brush along drainages. Breeding is in July–August and implantation is delayed until spring. Found in most habitats through large range, especially near water.
BLACK-FOOTED FERRET Mustela nigripes 490–600mm, 107–140mm, 915–1125g; 479–518mm, 120–141mm, 645–850g
This masked weasel survives only in captivity and in a few recently reintroduced wild populations in western states. Unique with a sandy-colored body and dark feet, tail tip, and facial mask. Difficult to see, they are nocturnal and terrestrial, and may remain in prairie dog burrows for extended periods in winter. Presence is indicated by tracks in snow, and in digging for prey they often leave a distinctive pile of soil on the surface measuring about 100×40×10cm. Breeding is in March–April, gestation is 42–45 days, and litter size is 3 or 4. Reclaiming prairie dog towns and surrounding areas in western grasslands, now reintroduced in parts of their historic range in Wyoming, South Dakota, Montana, and Arizona.
PLATE 86
SPOTTED AND HOG-NOSED SKUNKS
SPOTTED SKUNKS-Unique with their glossy, jet-black fur and white spots beginning near the ears and forming a pair of dashed lines down the back. Although some consider them to be one species, these two small skunks were recently split into an Eastern and Western species based on genetic and reproductive evidence: the Western Spotted Skunk has delayed implantation but the Eastern does not. Externally the Western Spotted Skunk has more extensive white markings than its Eastern cousin. They typically warn potential predators with their trademark handstand before spraying. These two quickest and most agile skunks are also the most carnivorous, catching mice, insects, and other small prey in their nocturnal hunts.
WESTERN SPOTTED SKUNK Spilogale gracilis 35–58cm, 10–21cm, 500–900g; 32–47cm, 200–600g
A small spotted skunk with large white spots on the face, back, and tail. Faster, more agile, and weasel-like than most skunks, and highly carnivorous. Diet includes small mammals, birds, lizards, insects, and carrion. Pungent anal scent glands provide a defensive spray, which is accompanied by a curious handstand and tail display. Breeding is in the fall, and delayed implantation results in 2–6 young born in spring. Uses rocky and brushy areas in woodlands, grasslands, farmlands, and deserts.
EASTERN SPOTTED SKUNK Spilogale putorius 31–61cm, 8–28cm, 276–885g; 27–54cm, 9–21cm, 207–475g
Small skunk with thin white spots and a small white tip to a mostly black tail. Larger than Western Spotted Skunk in area of overlap. Primarily nocturnal, secretive, and rarely seen. Feed heavily on mice, birds, bird eggs, and insects, as well as occasional fruits and vegetables if available. Cracks eggs by hiking them back between the hind legs like a football center. Breeding is in spring, with short delayed implantation, unlike S.gracilis. Avoids open areas, preferring habitats with extensive cover, especially riparian woodlands.
AMERICAN HOG-N
OSED SKUNK Conepatus leuconotus 40–92cm, 13–41cm, 1.1–4.5kg
Named for its unique long, naked nose pad, this skunk has coarse, long black fur marked with a white stripe down the back. Claws are well developed for digging up insect prey. Previously recognized as two separate species, the two forms are now viewed as subspecies. The smaller eastern subspecies from southern Texas and Mexico has a white dorsal stripe that is narrow, especially on the rump, with a tail that is black on the underside near the base (caution when looking for this character on live animals!). The larger western subspecies(C. l. mesoleucus) has a broader stripe and no black on the underside of its tail. Males are larger than females. Infrequent recent sightings raise concern over conservation status in some areas. Recorded from brush and semiopen grassland in southern Texas, and rocky terrain including stream beds in desert-scrub and mesquite grasslands further west.
Mammals of North America Page 15