PLATE 93
GOATS AND SHEEP
MOUNTAIN GOAT Oreamnos americanus 1.2–1.8m, 8–20cm, 46–136kg; 1.3–1.5m, 8–14cm, 45–83kg
A white goat with small, slightly curved black horns. White coat is long and shaggy in the winter and shorter in the summer. Males are larger, with longer horns. Similar to female Dall’s Sheep, but with black, not brown horns. Hooves are specialized for gripping rock. Males display and fight among themselves for access to females, and dominance hierarchies are established on the outcome. Breeding season is November–January, and one or two 2–3km young are born in May–June, usually on a steep cliff. The precocial young follow the mother immediately. Lactation lasts until fall, but young remain with mothers until the next birth. Juvenile mortality is high, but adult mortality low. Females first breed at age 3, and males somewhat later. Maximum longevity is 20 years in the wild. Typically migrates down slope in the winter with the first snowfall and uphill in the summer. Uses open country above the timberline, with meadows for foraging and steep rocky cliffs or talus slopes for refuge from predators.
BIGHORN SHEEP Ovis canadensis 1.6–1.9m, 8–12cm, 75–135kg; 1.5–1.7m, 7–12cm, 48–85kg
A brown sheep with a white rump patch and large curved horns that symbolizes mountain wilderness in North America. Large male horns are used in combat to establish dominance. Female horns are smaller. Easily distinguished from Dall’s Sheep by color and geographic range. In spring molt, cream-colored females are distinguished from Mountain Goats by coat and horn color. Heaviest in October, lightest in May. Measurements given are for O. c. canadensis from the central and northern Rockies, the largest subspecies. Often seen at saltlicks. Typically in groups of 5–80 animals. Many populations are migratory, moving between summer and winter ranges. Limited by water availability in desert habitats, where many isolated populations are declining and the subspecies O. c. californiana from California is Endangered. Prefers treeless areas with nearby cliffs or rocky areas to escape from predators.
DALL’S SHEEP Ovis dalli 1.3–1.8m, 7–12cm, 73–110kg; 1.3–1.6m, 7–9cm, 46–50kg
A northern sheep with large horns that grow continuously through life. Coat color is usually uniform white; the subspecies O. d. stonei from Yukon and British Columbia is silvery gray with a white muzzle, leg trimmings, and rump patch. Male is larger than female, with larger horns. Horns are a bit smaller than in the Bighorn Sheep, and more widely flaring. Winter coat is much thicker. Gregarious, but males and females come together only during the rut. Males fight for access to females using the huge horns to ram each other. Breeding season is November and December, and a single lamb is born in May after 171–day gestation period, on high, precipitous cliffs. Lambs weigh 3–4kg at birth, are precocial, and follow their mother the first day. They are weaned at 3–5 months, and weigh 30kg by 9 months. Feeds on grasses and low shrubs. Typically migrates between summer and winter ranges in its rugged mountain habitat.
PLATE 94
BISON AND NILGAI
AMERICAN BISON Bison bison 3.0–3.8m, 43–90cm, 460–907kg; 2.1–3.2m, 43–90cm, 360–544kg
North America’s largest land mammal. Has a distinctive humped profile with larger forequarters and smaller hindquarters; these traits are more pronounced in males. The brown wooly pelage is thickest around the neck, extending onto the shoulders and back in males. Males also have larger horns, which are stouter and more curled; female horns are more slender with upward pointing tips. Calves are reddish. Hair is longer in the winter. The Endangered Wood Bison(B. b. athabascae) from western Canada is slightly taller, darker, and woolier, with a larger hump than the Plains Bison(B. b. bison). Wallows 2–3m wide are used by all ages and sexes. Prairie rock rubs worn smooth by 10,000 years of use usually rest at the bottom of a slight depression formed by countless hoofs circling the stone as the bison rubbed against it. Tens of millions of bison were nearly hunted to extinction (probably fewer than 1000 animals left) at the end of the nineteenth century, the species had recovered to ca. 150,000 animals by 1995, with 90% privately owned. Typically grazes in herds of 4–20, these groups sometimes merge into much larger congregations. Herds provide protection from predators, and stampedes are a predator-avoidance behavior. Breeding season is July–August, gestation length is 285 days, and females have only a single calf with birth coinciding with spring greenup. Females leave the herd and lie down to give birth. The female fiercely defends the newborn calf. Sexual maturity is reached at age 2. Males have a repertoire of threat displays, both visual and vocal, to establish dominance relationships, but rarely resort to all-out battles. When they do occur, these battles are epic, the large bulls slamming into each other, shearing out gouts of hair with their horns, and on rare occasions, dying from a horn that penetrates the ribcage. Most breeding happens in a 2–week period, and the one-third of the males that are dominant breed with two-thirds of the females. This means that the large male bison are heavily selected for fighting specialists, while the much smaller females reproductive success depends more on competition for food. When a cow comes into estrus, she is quickly tended by a bull, who may then be replaced by a more dominant bull. Reaching their highest density in mixed and short-grass prairies, these gregarious grazers can survive in a variety of open habitats.
NILGAI Boselaphus tragocamelus 2.2–2.4m, 40–45cm, 109–306kg; 109–213kg
A very large, brownish exotic antelope introduced and running wild in Texas, especially south in Kennedy and Willacy counties. This large animal stands up to 1.5m at its enlarged shoulders; its profile then slopes to the smaller rump. Generally brownish, the bull is slightly gray while the female and young are orangish brown. It has white on the face, chin, and throat. Below this white bib hangs a beard of hair, which is larger in males. Female is smaller and generally lacks horns. Typically herds in groups of 10. Intolerant of cold temperatures. Grazes and browses in relatively dry areas of flat to rolling country with a moderate cover of thin forest or scrub. Avoids heavy woods.
PLATE 95
ARCTIC UNGULATES
CARIBOU Rangifer tarandus 1.6–2.1m, 11–22cm, 81–153kg; 1.4–1.9m, 10–20cm, 63–94kg
A stocky deer of the far north. Both sexes have antlers; male antlers are larger and semi-palmated, especially the single, flat brow tine that extends down almost, but not quite, past the nose; female antlers are much smaller and less palmate. Female tends to have more white hairs than bulls. Old antlers are whitish, new ones are black from their velvet covering. Coloration and antler size vary across subspecies. The Woodland Caribou from boreal forests and alpine tundra is the largest caribou, and is brown in the summer and grayish in the winter. It has creamy white hair on the neck, mane, underbelly, rump, and on a patch above each hoof. Barren Ground Caribou uses taiga forests and tundra and is medium in size; the coat is chocolate brown in summer, lighter brown in winter. Pearly Caribou from high Arctic islands is smaller with shorter legs, face, and ears, and a lighter coloration. Caribou eat grasses and shrubbery leaves in the summer, lichens in the winter, a food not used by other members of the deer family. Large migratory herds calve on the tundra in the spring, then wander the tundra and forest searching for food. Females can more easily detect predators on the open tundra, but in the winter forested regions offer the best forage in the form of lichens, which they reach by digging in the snow. Forest and mountain Caribou migrate less. The Woodland Caribou subspecies (R. t. caribou) is Endangered. Domesticated and European Caribou are known as Reindeer. Depending on the subspecies and time of year, the Caribou uses a variety of boreal forest and treeless tundra and mountain habitats, which are among the harshest and least productive of those used by any member of the deer family.
MUSKOX Ovibos moschatus 2.1–2.6m, 7–12cm, 186–410kg; 1.9–2.4m, 6–12cm, 160–191kg
A stocky, shaggy bovid of the Arctic. The long, brown winter hairs extend nearly to the ground, covering fine, cashmere-like underhairs. Stockings and saddle are creamy white. Male is larger (some reach 650kg in capti
vity) and has larger horns that merge into a massive boss on the forehead. Female horns are shorter, more slender, and more curved. Feeds on sedges, grasses, and willows, and distribution is limited by snow depth. Typically lives in mixed-sex groups, although some males are solitary in summer. Sedentary groups move little, but adult males move more than females. When confronted by would-be predators, adults circle around calves, confronting the enemy with a ring of pointy horns. Herds may also stampede when disturbed. Nearly extinct at the end of the nineteenth century, now protected, reestablished in Alaska, and recovering in Canada, where most of the population lives on Arctic islands. Males defend harems during the August–September breeding season through a variety of displays, vocalizations, and scent-marking. The culmination is an all-out charge with males running together at 50km per hour and banging heads with the huge horn bosses taking the brunt of the blow. Females give birth to a single calf (rarely twins) in April–May after a 34–week gestation period. Uses Arctic tundra, preferring grassy areas with low precipitation in the short, cool summer and windswept areas with exposed vegetation in the long, cold winter.
PLATE 96
ELK AND MOOSE
ELK Cervus elaphus 2.1–2.6m, 11–17cm, 178–479kg; 2.0–2.5m, 8–19cm, 171–292kg
A large, tan-colored ungulate with a darker neck and white rump. In season, the male has a shaggy neck mane and enormous antlers consisting of one main beam and, typically, six points. Antlers are usually shed in February and regrow over the summer. Summer coat is sleek and tawny brown; winter coat is grayish brown. Fawns are spotted. Tule Elk(C. e. nannodes) from parts of California are lighter overall in color and smaller. The Elk is smaller and paler than the Moose, without palmate antlers; larger than deer, with unique dark neck/white rump coloration. During the fall rut in September–October, males repeatedly give a high-pitched “bugle” vocalization. Yearlings of both sexes can breed, and the gestation period is 240 days, with a single calf (rarely twins) born in June. Newborns weigh about 15kg. Lives in herds sometimes exceeding 200 in open habitats, smaller groups in forested areas. Maximum life expectancy is 20 years. Hunted to extinction throughout eastern states by the mid 1800s; recent reintroductions of small populations into Michigan, Kentucky, Tennessee, and Pennsylvania are encouraging. Overall population size is now approaching a million animals. The smaller C. elaphus subspecies from Europe is called the Red Deer and typically has rougher antlers that grow up and inward rather than up, out and backward. Browses and grazes on a variety of plant species, preferring open or brushy habitats to mature forest. Most populations in the US are found on federally protected lands such as national parks, forests, and wildlife refuges.
MOOSE Alces americanus 2.4–3.1m, 8–12cm, 360–600kg; 2.3–3.0m, 8–12cm, 270–400kg
Largest deer, and one of the largest land mammals in North America. Elongated head with pendulous snout, unique hanging dewlap, and huge rotatable ears that provide an excellent sense of hearing. Upper lip marked by small rectangular bare spot. Long legs gray at bottom. Heavy body with humped shoulders and a small tail. Light brown to black body color from guard hairs over gray undercoat that provide ample protection from cold, snowy winters. Male is larger than the female and bears enormous palmate antlers (largest in the world) that are grown in summer and shed in winter. Most females have white hair around vulva. Juvenile pelage is reddish. Recently recognized as a distinct species from the Eurasian A. alces. Large size and a total population size of around a million means considerable ecological impact, both as browser and as prey. Mostly solitary; herbivorous; active any time, especially dusk and dawn, and most of its activity is dedicated to foraging for the 65kg of plant food that its stomach can hold. Keen sense of smell allows them to locate food beneath the snow, but vision is not as acute. Vocalizations in the early fall rut include deep grunts and moos. Mud wallows marked by large tracks; most antler rubs on vegetation are higher (100–200cm) than deer (less than 115cm). Recently reintroduced in Colorado and northern Michigan. Can be seen cooling themselves in ponds and lakes, or standing in the shade, where they are often unwary but can be dangerous up-close; abundant in northern boreal forests, especially wet areas, and limited to cool regions where temperatures do not exceed 27°C.
PLATE 97
NATIVE DEER
DEER-These two deer species are among our most familiar animals. They are distinguished by differences in the ears, facial coloration, tail, and antlers. Hybrids are rare, and typically sterile. In areas of overlap, the Mule Deer inhabits drier habitats. The White-tailed Deer sticks to moister habitats, and is expanding its range westward. Both leave their sign on the landscape in similar ways. Antlers are rubbed on the stems of saplings, scraping away the bark. Bark scraped off with their incisors leaves a different, chewed pattern on small trees. Chewed branch ends are cut off roughly, leaving a frayed end, typically around human knee-or hip-height. Matted grass beds mark their resting sites. Finally, males mark their areas with dirt scrapes dug by their hooves and flagged with broken branches above and urine scent in the mud.
MULE DEER Odocoileus hemionus 1.3–1.7m, 13–22cm, 40–120kg; 1.2–1.6m, 12–21cm, 30–80kg
Ears are larger and tail is smaller than that of the White-tailed Deer. Males have dichotomously branching antlers that are usually shed in January and regrow over the summer. The tail is large and black in coastal subspecies, smaller with a black tip in interior subspecies. Interior animals are pale brown or tan in the winter with a large white rump patch, while coastal animals are darker and grayer with a smaller white rump patch. All races are rusty red in new summer coat. Fawns are reddish with white spots. There is a V-shaped dark mark from the point between the eyes, upward and laterally, especially in males. When alarmed they bound away in a “stot,” with four feet hitting the ground together at each bound (the White-tailed Deer springs from hind to front feet). Populations in northern mountains migrate up to higher elevations in the summer and down to the foothills in the winter. Prefers mixed habitat with both open areas for feeding and forest or brushy areas for protection. Common in western mountain forests, deserts, and brushlands.
WHITE-TAILED DEER Odocoileus virginianus 0.8–2.4m, 10–37cm, 22–137kg; 30–90kg
Ears are smaller and tail is larger and whiter than in the Mule Deer. Males have antlers consisting of smaller vertical tines branching off the single main beam. Year-old male fawns have small “buttons” of antlers. Antlers are shed in December and January and regrown over the summer. Long tail is brown above, white below, and fringed in white on the sides. Coat is reddish brown to bright tan in the summer, duller and grayer in the winter. Fawns are reddish and spotted with white. Males average 20% larger than females and northern populations are larger; the Endangered Dwarf Key Deer (O.v. clavium) from the Florida Keys stands 60cm at the shoulder and weighs ca. 35kg. The Columbian White-tailed Deer subspecies (O.v. leucurus) from coastal Oregon and Washington is also Endangered. Once thought to number 40 million, populations were reduced to about a half million by the end of the nineteenth century. Subsequent management resulted in rebounding populations that now number 15 million in the US alone, with an annual hunter harvest of 2 million. Prefers forest edges and open woodlands near brushlands, especially old fields and agricultural areas. Uses a variety of forested habitats from temperate to tropical, semiarid to rain forest, making it one of our most widespread species.
PLATE 98
EXOTIC UNGULATES
These non-native species have been introduced for hunting purposes and occasionally form feral, reproducing populations in isolated areas.
FALLOW DEER Dama dama 1.4–2.0m, 15–23cm, 79–102kg; 36–41kg
An exotic spotted deer with palmate antlers. Originally from the Mediterranean, escapes and releases from game farms have started free-ranging populations in at least seven states and provinces (California, Georgia, Texas, Alabama, Kentucky, New Mexico, and New Brunswick) and islands off British Columbia; many less successful introductions have also occurred. Most an
imals are rust or tan-colored, with white rump patch and belly; winter pelage is darker and the spots are often indiscernible. The white spots on the back merge into a white line near the rump and there is a black or tan line on the back. Melanistic, very dark, and very light morphs are also known, and may predominate in domesticated herds. Prefers mixed habitats with open areas for feeding and covered areas for winter food and shelter.
CHITAL Axis axis 1.0–1.75m, 12–38cm, 30–75 kg; 25–45kg
A spotted exotic deer with three tines on each antler. This brownish deer has many delicate white spots, and a white abdomen, rump, throat, insides of legs and ears, and underside of tail. A dark stripe runs down the center of the back. Originally from India, Nepal, and Sri Lanka; they are now the most abundant exotic ungulate in Texas. Many have escaped from game farms in other states and probably also survive in the wild in California and Florida. Prefers secondary forests mixed with grassy areas.
SIKA DEER Cervus nippon 1.0–1.5m, 7–13cm, 68–109kg; 45–50kg
A small deer from east Asia with introduced feral populations surviving in Texas and Maryland. This compact deer has a distinctive wedge-shaped head. Dark brown with a variable amount of white spotting that is absent in some animals. Texas populations are especially variable due to extensive hybridization. There is a white rump patch that is most visible when the animal is alerted. The male’s antlers have three or four points branching off each main beam; the female has a corresponding pair of black bumps on the forehead. Browses and grazes in a variety of woodlands.
Mammals of North America Page 17
