Biology

Scientific name: Cervus elaphus

Subspecies

• Rocky Mountain (Rocky Mountain West)
• Roosevelt's (Pacific Coast)
• Tule (Central California)
• Manitoban (northern Great Plains)
• Merriam's (Southwest and Mexico) - Extinct
• Eastern (east of the Mississippi) - Extinct

Calves

Calves are typically born from late May through early June. Born spotted and scentless, they spend their first few weeks hiding motionless while their mothers feed.

Behavior

The Rut

• Elk breed in the fall
• Bulls gather cows and calves into small groups called harems
• Bulls wallow in mud to coat themselves with "perfume" to attract cows
• They also bugle and rub trees, shrubs and the ground with their antlers to attract cows and intimidate other bulls
• Bulls aggressively guard their harems from other bulls
• Sometimes, bulls wage violent battles for a harem, occasionally even fighting to the death

Social Organization

• Cows, calves and yearlings live in loose herds or groups
• Bulls live in bachelor groups or alone
• During the rut, cows and calves form harems with one or two mature bulls

Body Postures

• When alarmed, elk raise their heads high, open their eyes wide, move stiffly and rotate their ears to listen
• If a harem cow wanders, a bull stretches his neck out low, tips up his nose, tilts his antlers back and circles her
• Elk threaten each other by curling back their upper lip, grinding their teeth and hissing softly
• Agitated elk hold their heads high, lay their ears back and flare their nostrils, and sometimes even punch with their front hooves

Vocalizations

• Bull elk bugle to attract cows and advertise their dominance to other bulls - LISTEN
• Bull elk grunt at cows straying from their harem
• Cows bark to warn others of danger - LISTEN
• Cows mew to keep track of one another - LISTEN
• Cows signal to their calves by whining softly
• Calves in distress bleat for their mothers

All in the Family

Elk and other members of the deer family belong to a group of animals called ungulates, the Latin word for "hoof." All ungulates have hooves. This large group used to be considered one order, but now "ungulates" refers to two distinct orders, Artiodactyla and Perissodactyla. The number of toes is the most obvious difference between the orders. Artiodactyls (elk, deer, bison, pronghorn, peccary) have an even number of toes. Perissodactyls (horses, elephants) have an odd number of toes.

Elk, moose, caribou, white-tailed deer and mule deer all belong to the order Artiodactyla and to the deer family, Cervidae. The males of these species grow and shed antlers each year. (Female caribou also grow and shed antlers.)

Like other ungulates, members of the deer family are herbivores -- they eat only plants. Their diet may include grasses, forbs (low-growing, short-stemmed plants), shrubs and trees (including limbs and bark).

Members of the deer family must eat and watch for predators at the same time. Elk fulfill these double needs by gathering in herds. In a group, at least one animal is looking up while others are eating. Even the animals that are feeding are constantly twitching and turning their ears to listen for unusual or warning sounds.

Some deer family members migrate, following their food sources as the seasons change. Some caribou migrate hundreds of miles twice a year as they follow the seasons. Most elk that live in mountainous country migrate to lower elevations as snow covers the higher elevations, then return as snow retreats in the spring and summer.

Wherever you live in North America, you are likely to be near at least one member of the deer family. White-tailed deer live throughout the lower United States; mule deer browse in the western states and provinces; moose inhabit riparian areas (banks of rivers and other bodies of water) across the north; and caribou can be found in northern Idaho, Alaska and Canada. Elk used to live across North America, but these days you are most likely to find them in the western states and provinces.

About Antlers

Each spring, male deer and elk begin growing antlers from bony bumps on their skulls called pedicles. Increasing daylight elevates the level of the hormone testosterone in the animal's blood, which triggers the growth of antlers. Antlers begin as layer upon layer of cartilage that slowly mineralizes into bone. They are light and easily damaged until they completely mineralize in late summer. A soft covering called velvet helps protect the antlers and carries blood to the growing bone tissue.

If you look closely at a deer or elk antler, you'll see grooves and ridges on it. These mark the paths of veins that carried blood throughout the growing antlers. When blood stops flowing to the antlers in August, they harden, and the velvet falls off or is rubbed off. The hardened antlers are composed of calcium, phosphorous and as much as 50 percent water.

An antler grows faster than any other kind of bone. It can grow up to one inch (2.5 cm) per day during the summer. Biologists are studying antlers in hopes of learning the secrets of rampant cell growth--secrets that may unlock cures to various forms of cancer.

In his second year, a bull elk usually grows slim, unbranched antlers called spikes that are 10-20 inches (25-50 cm) long. By the third year, antlers begin developing tines that branch from the main beam. By the seventh summer, a bull's antlers may have six tines each, weigh as much as 40 pounds (18 kg), and grow to a length and spread of more than four feet (1.2 m). Why would an animal need to carry around a rack of antlers that weighs so much? A large rack identifies a bull that is successful in finding food, lots of food.

A bull must consume huge amounts of nutrients to obtain the energy and minerals needed to grow antlers as well as the energy to carry them around. Large antlers also identify a bull that is able to defend himself against other bulls and against predators. This information is of great interest to female elk (cows) because they will mate with the strongest, most successful males -- usually the bulls with the biggest antlers.

Antlers

• Only male elk have antlers
• Bulls shed and grow a new set of antlers every year
• New antlers are covered in fuzzy skin called velvet
• Antlers harden by late summer and the velvet peels away
• By September, antlers are solid bone
• A set of antlers on a mature bull can weigh up to 40 pounds

Inside Stomachs

Elk and other members of the deer family eat tough plants such as grass or twigs that most other mammals can't digest. Elk digest these plants in multi-chambered stomachs, a trait of the suborder Ruminantia. (Cattle, sheep and their wild cousins are also ruminants.) The root of the name comes from "rumen," the first of three or four chambers of a ruminant stomach. These chambers create a system for digesting tough plant fibers and extracting the maximum nutritional value from them.

To understand how this "super stomach" works, imagine a cow elk as she nips off twigs, clips leaves and crops grasses. This constant biting, pulling and clipping sends as much as 15 pounds (7 kg) of tough plant fiber into the elk's stomach each day. The unchewed material slides into the rumen, the first chamber. There bacteria and protozoa begin breaking down the plant material. Then the elk regurgitates her food (the cud) and ruminates (chews cud thoroughly).

When the cud is completely chewed, the elk swallows it again. The food particles pass through the rumen and into the reticulum, the second chamber, for even more digestion. Then the food passes into the omasum, the third chamber, where water is squeezed out and absorbed into the elk's body. Finally, the food passes into the abomasum, the fourth and "true" stomach, where it is broken down to the molecular level so that it can be absorbed by the intestine.

Secrets of Teeth

Like other deer, adult elk have sharp incisors for biting off plants, and broad, flat molars for mashing plants. Molars line both the upper and lower jaw, but incisors occur only on the lower jaw. Elk also grow two canines (also called tusks, ivories, whistlers or buglers) in the upper jaw.

When biologists want to determine an elk's age, they look at the teeth, not the antlers. Teeth are a better gauge because antler size can vary depending on the health of the bull, and cows don't grow antlers. To "age" the teeth, biologists place a cross section of an elk's tooth under a microscope and count the annual growth rings.

The type of teeth in an elk's mouth and the amount of wear they show can also indicate the animal's approximate age. To figure the age of a young elk, a biologist observes how many adult teeth have replaced the "baby" incisors and premolars. This transition is completed by the end of the third year. Older elk can be identified by the amount of wear on their molars because chewing tough plant fiber will wear down even the sturdiest of teeth.

Ivories

• An elk's top two canine teeth are called ivories
• Scientists believe ivories are remnants of saber-like tusks that ancestral species of elk used in combat
• Most hunters save ivories as a memento of the hunt

Diet

• Summer = Grasses and forbs
• Spring and fall = Grasses
• Winter = Grasses, shrubs, tree bark and twigs
• Elk may supplement their diet at licks, where they take in minerals that may help them grow healthy coats and produce nutritious milk
• An elk's stomach has four chambers: the first stores food, and the other three digest it.

In the Open

Although we primarily see elk in mountainous and forested terrain today, they are also well suited to open spaces. Some scientists believe that an elk's body and senses reflect adaptations for the lifestyle of a herd animal that once roamed the plains for its food.

An elk's long legs are packed with powerful muscles designed for speed and endurance. A strong heart and lungs pump blood and air to those muscles to keep them moving, and move is what elk do to find enough food to eat throughout the year. They also need to escape predators such as wolves, mountain lions and grizzly bears.

Elk have keen senses that enable them to identify each other over long distances and to detect approaching predators. Unlike human eyes that can see precise images, an elk's eyes are designed to detect movement, even the slightest shifting of grass as a predator approaches. To an elk, knowing that something is moving closer is more important than identifying the kind of animal approaching. And because their big eyes are on the sides of the skull, elk can see what is happening ahead of them and beside them, as well as most of what is going on behind them.

Likewise, their big ears can twist forward and back to capture faint rustlings and other sounds of movement. Elk also seem to have a superb sense of smell. Combine the sharp senses of a group of five, 10, or even 50 elk and it's easy to understand how they avoid predators. In the next two sections, "Where Are The Elk" and "Elk Through The Seasons," you'll discover how their habitat and behavior also help them to stay safe.

Elk Habitat - Just what is habitat, anyway? It's food, water, shelter and space. These are the four basics for all animals -- whether it's elk, elephants or elf owls -- and people, too.

Food

The need for food is obvious. Picture a 900-pound bull elk grazing in a meadow of bunchgrass. The bull's hoof thumps down beside the nest of a field mouse. When the mouse panics and flushes, it's pounced on by a shrew that weighs no more than a quarter. Both the elk and the shrew rely on the same habitat -- and are driven by the same hunger.

Well actually, the shrew may be a little hungrier. Elk need 10 to 15 pounds of vegetation per day, but shrews have to eat their own weight in insects, earthworms or mice every day or starve. Elk can go a bit longer between meals. But like all animals, they cannot survive for very long without food.

Water

Water is just as critical. Your body, an elk's body, a weasel's body... is all wet. If all the water in your body were removed, you would weigh about as much as a dictionary.

Naturally, elk and other animals are drawn to water holes -- springs, seeps, lakes, creeks -- but there's more than one way to come by water. A sharp-tailed grouse that shares grasslands and wild rose thickets with elk can get all the water it needs by sipping dew and eating juicy plants. Elk use these same techniques, and they also eat snow to quench their thirst.

Shelter

After getting enough food and water, elk look for shelter. Shelter works two ways. It protects animals from cold, rain and snow. And it gives them a place to hide from predators.

On a bitter, cold, snowy day, a band of elk may "hole up" in a big stand of spruce trees. These trees form a great green blanket, holding warmer air near the ground. The spruce also take the bite out of the wind. And their tightly woven branches catch much of the snow before it hits the ground. This same patch of timber also offers shelter (and food) to a variety of songbirds, chickadees, nuthatches, grosbeaks -- and maybe even a red fox.

When people and mountain lions are hunting elk in October, the elk head for the north slopes of mountains and burrow into thick stands of dark timber. Lurking among the deadfalls where pine martens live, the wary elk position themselves so they can smell, hear and see any intruder long before they themselves are seen.

Staying Comfortable

• In cold snowy climates, cows, calves and young bulls migrate to foothills and valleys in winter
• An experienced elk, usually the lead cow, guides a herd between seasonal ranges

Thermoregulation

Winter

• Elk grow winter coats consisting of long, waterproof guard hairs covering dense, woolly underfur
• During the day, elk feed on open, sunny slopes
• Elk bed down in the trees at night to seek shelter from wind and cold temperatures

Summer

• An elk's summer coat consists of short, stiff, relatively sparse hairs
• Elk bed down in cool, shady forests during the day
• Elk wade or lie in streams, rivers, ponds and lakes to seek relief from heat and biting insects
• Blood pumping through the veins in the velvet on a bull's antlers cools before it returns to the heart to help cool the animal

Space

Every animal needs room to roam. For a mature male mountain lion, that means a lot of room. A big tom can have a home range of more than 100 square miles. That's as big as an entire county in some states. Elk like to ramble, too. They have been documented trekking more than 50 miles in a single day.

But a ground squirrel may spend a whole year on a chunk of range no bigger than a football field. And a beetle may live out its life on a slice of elk country the size of a wading pool. The beetle needs its space -- the area in which it finds the critical triangle of food, water and shelter -- just as much as elk do.

Elk country is home to all sorts of wildlife -- from tiger salamanders to zebra swallowtails to cutthroat trout. These creatures don't have antlers or horns or big brown eyes. But they're all vital strands in the web of life.

When an old bull dies in February, coyotes, ravens, vultures, and magpies quickly clean up the meat. Next spring, gophers gnaw on the bones for calcium and other minerals. When one of the gophers dies, beetles eat its decomposing carcass. And what's left over decays into the earth and is reborn as more nutritious grass.

All of the creatures in elk country have evolved over thousands--perhaps millions--of years to live in a specific habitat. When the rug is yanked out from under them -- when their food, water, shelter or space is suddenly altered or destroyed -- many of them cannot adapt quickly enough to survive.

Given a chance, the land can allow these animals to live naturally. All they need is habitat.

Populations and Habitats

From an ecological point of view, individuals of an animal species are less important than populations. Only populations can survive and adapt over the long term.

"Habitat" is the foundation on which wildlife populations are built. Habitat is a particular combination of (1) food, (2) water, (3) cover and (4) space needed by individuals and populations to live and thrive. The quantity and quality of these habitat components generally dictate the type and number of animals that can live and persist in a particular area.

Habitats are always changing -- seasonally, annually and over longer periods. Such changes can be the result of seasons (spring, fall, etc.), natural catastrophe (flood, drought, tornado, wildfire, etc.), plant succession (a field growing up to forest, for example) or human action (agriculture, dams, logging, pollution, etc). Thus, while the number of animals that any habitat can support always is limited, the actual population can sometimes vary drastically over time.