The wolf is the largest wild member of the canidae or dog family. Many of the wolf's physical and behavioral characteristics reflect the fact that it cooperatively hunts pursues attacks kills and eats animals larger than itself.
Subspecies of wolves
Based largely on the work of Goldman (1944) 24 subspecies of wolves are recognized in North America. However Goldman did not employ statistical analysis and had relatively few specimens from some regions. In addition, there are documented cases of wolves crossing subspecies boundaries during dispersals (Fritts 1983). Analysis of current skull collections by Nowak (1984) led him to propose that the number of wolf subspecies be greatly reduced. Regardless of the final taxonomical a conclusion, wolves are remarkably similar physically and behaviorally; without extensive skull measurements, subspecies identification is impossible.
Physical appearance of wolves and similar species
Wolves in the Rockies usually weigh 70 to 115 Ibs. (32-52 kg), with males tending toward the higher end of the spectrum. They average 26 to 32 inches (65-80 cm) tall at the shoulder and measure 57 to 76 inches (145-193 cm) in length (Ream et al. 1987). The tail is long and bushy and is usually carried down or straight out, never curled. Ears are erect, rounded and 2 inches (5 an) long. Eyes are yellow and eyeshine is greenish gold (Burt and Grossenheider 1964).
Table I: Differences in Physical appearance between canids
|Height at Shoulder||26-34 in.||16-20 in.||Variable|
|Color||black, white, all shades of gray & tan, grizzled, never spotted||all shades of gray & tan, white or black very rare, never spotted.||Variable, may be spotted|
|Tail Carriage||hangs down or straight out, never curls||hands down or straight out, never curls||Variable, may curl|
|General Appearance||massive, long legged, first impression is often calf or deer||delicate, medium size, dog-like proportions with fox-like face.||Variable|
|Ears||rounded, relatively short, never hang down||pointed, relatively long, never hang down||Variable, may hang down|
|Muzzle||large and blocky||long and pointed||Variable|
Wolves' chests are narrow and keel-like, and their fore limbs seem pressed into their chests with elbows turned inward and paws turned outward (Young 1944, Iljin 1941). Milton Hildebrand analyzed the body proportions of various members of the dog family and concluded that wolves' legs are moderately long compared to the legs of other canids (Mech 1970)
Color ranges from white to black shades of brown and gray. White and light-colored waives predominate in the arctic, while black and gray are common in the subarctic and boreal forest regions (Banfield 1974). Gray phases prevail in the south. The wolves in north-western Montana are predominantly gray (45% ) or black (55% ) (Ream et al. 1987). The coat consists of a dense layer of soft, fine fur topped by long guard hairs, which give the coat its color (Mecli 1970).
The longest hair, as long as 6.7 inches (16.75 cm), is found in the mane. Wolves can raise and lower this hair depending on their state of aggression (Carbyn 1987). The mane hair, along with hair on the base of tail, is generally darker than the rest of the body. Patterns of color in facial hair accentuate expressive features. Wolves appear lankier and less robust in summer due to a much thinner coat.
It is difficult to distinguish between wolves, coyotes and dogs, especially if the light is bad, the sighting is brief or the animal is far away. Table I show key characteristics of wolves, coyotes, and two breeds of dogs that can be easily mistaken for wolves. Because of their relatively long legs and lanky body, the first impression of a wolf is often that of a deer or calf, not of a large dog or coyote. Skulls of wolves, dogs and coyotes can usually be distinguished by measurements of teeth, orbital angle and the angle at which the rostrum and brain-case meet (4748: Hoffmann and Pattie 1968). Hybrids are more difficult and may be misclassified even with sophisticated measurements.
Differentiating wolf hair from other species
Currently no techniques exist for distinguishing between wolf and coyote hair. However, the hair of these two species can be distinguished from other members of the Canidae family through microscopic analysis (Kennedy 1982, Moore et al. 1974). Inquiries regarding canid hair identification may be sent toA.J. Kennedy, Predator Laboratory Services, 11416 - 50th Ave., Edmonton, Alberta, Canada, T6H OJ3. A technique that shows promise, but has not yet been tested with wolves and coyotes, is isoelectric focusing. This technique relies on examination of hair protein, which appears to be diagnostic for species and even breeds of domestic dogs (Carracedo et al. 1987). The Wyoming Fish and Game Laboratory is currently studying this technique. Inquiries as to its status may be directed toWyoming Fish and Game, University Station, Box 3312, Lararnie, WY 82071.
Differentiating wolves from other species.
Wolves, dogs and coyotes are nearly identical genetically, and no tested method exists for distinguishing them on that basis (Robert Wayne, Dept. Biol., U.C., Los Angeles, pers. common.). Obviously, hybrids of 2 or more of the species are even more confusing. Work is being done in this area, and samples of tissue or heparinized blood may be sent to Robert Wayne, Dept. Biol., U.C.-Los Angeles, Los Angeles, CA 90024 or U.S.F.W.S., Division of Law Enforcement, 1490 E. Main St., Ashland, OR 97520. Investigators should contact the above labs for sample size, storage and shipping protocol.
Appearance of tracks of wolves and similar species
Wolves often travel long distances in the course of their daily activities. It is not uncommon for wolves to travel 20 miles in a as 24-hour period. Such distances are covered primarily at a trot. The wolf's stride length at a trot is generally more than that of other species with similar tracks. Stride is the distance from one footprint in a trail to the next footprint made by the same foot, and is usually the measurement found in track identification books. WEP has found that measurement of intergroup distance is easier and less subject to error than measurement of stride. Intergroup distance is the distance from one print to the next (fig. 11). Several intergroup distance measurements should be taken to determine an average.
A wolf's front feet are larger than its hind feet, and the toes spread more. The hind foot often lands in the print made by the front foot on the same side.
Wolf tracks are similar in shape to coyote and dog tracks (figs. 12-16) The track of a wolf is considerably larger than a coyote's, but tracks of some breeds of dogs overlap those of a wolf. Harris and Ream (1983) developed a method to aid in distinguishing between those dog breeds and wolf tracks. This method relies on measurements intergroup distance made from casts of undistorted tracks. See Harris and Ream (1983) for necessary measurements. The authors caution that this method should not be used in isolation, but in conjunction with other relevant information such as length of stride and track pattern. They also suggest that only tracks greater than 4 inches (11 cm) long be subjected to this method (Harris, pers. commun. ). Tracks less than this length may be assumed to be dogs or coyotes. Only a few breeds of dogs such as Great Danes, St. Bernards and blood hounds leave tracks longer than 4 inches, and the method can be used to eliminate these breeds. The tracks of German shepherds, malamutes, retrievers and setters are usually less than 4 inches long.
Since dogs have proportionally wider chests than wolves, the width of a dog's stride (straddle) is greater, especially for dogs with tracks as large as a wolf For the same reason, dogs place their hind foot beside their front, whereas wolves place their hind foot on the same line as the front foot (Mech 1970).
Wild canids and felids tend to walk straight, and their trails give the appearance that the animal is on a "bee-line." Quite often an imaginary line can be drawn through their tracks that is remarkably straight (fig. 17). Dogs tend to meander, giving their trails a zigzag appearance (fig. 18) (Dick Thiel, pers. common.). However, both species can vary and tracks should be followed for considerable distances before a decision as to species is made.
Appearance of nearby scats and proximity to people should be considered when large canid tracks are encountered. In some remote areas, large canid tracks may result from the practice of using hounds to hunt mountain lions (Felis concolor).
Mountain lion tracks are often confused with wolf tracks. Distinguishing features of a mountain lion track are its roundness, the shape of the planter pad (main foot pad) and asymmetry of both the foot and the individual toes (figs. 19, 20). The intergroup distance of a mountain lion is also less than wolves', though there is overlap. Because cats have retractable claws, mountain lion tracks do not usually show dew marks. This is not always true, however, as mountain lions sometimes use their claws to increase traction on steep or slippery terrain. Claw marks may also be present if the animal is traveling fast. If dew marks are visible, they will be directly joined to the toe, while the wolf track exhibits a 1/4-inch separation between claw and toe.
Table II and Figures 19-22 show distinguishing measurements and characteristics of tracks and intergroup distances for wolves and other species in the Rockies that can be confused with the wolf
WEP suggests that an observer first decide if the track was made by a predator or an ungulate. This can be difficult in loose deep snow, but generally you can distinguish the two, even at a distance, by imagining a line drawn down the center of a set of tracks. Predator tracks will be close to the center line because of their smaller chest width, while ungulate tracks will straddle the center line with wider separation (fig 23). Next, examine intergroup distance and the direction of travel. If intergroup distance is more than 24 inches (61 cm) and the direction of travel is straight, then inspect individual tracks.
The following measurements should be recorded: intergroup distance (fig. 11) and length and width of track (fig. 12). Tracks can appear elongated if the animal slips, and tracks in snow enlarge in warm weather. Track width is more variable than length because an animal can splay its toes in response to terrain. These factors must be kept in mind. A guide to animal tracks is an indispensable field aid. Murie (1974), Halfpenny (1986) and Forrest (1988) are very good.
Table II: Distinguishing track characteristics
|WOLF||4 toes, symmetrical, longer than wide, rectangular shape, typical canid-shaped planter pad, nail marks not attached to toe mark||>26"||L>4 3/4"
|travels straight line,|
|DOG||same as wolf||variable||variable most breeds
< 4" long
|lots of meandering|
|COYOTE||same as wolf||<16"||L<2 3/4"
|travels straight line,|
|COUGAR||4 toes, asymmetrical, typical felid-shaped planter pad, round shape, no nail marks usually, if present then attached to toe.||>20"||L>3"
W> 3 1/2"
|travels straight line, usually, may leave tail drag mark in soft deep snow|
|LYNX||same as cougar but with "feathery, blurred" appearance around print due to foot fur||<14"||L>3 1/2"
W 3 3/4"
|WOLVERINE||5 toes (small toe does not always show), nail marks unattached, mustelid-shaped planter pad (entire pad may nor show)||3-12"
(up to 35" when bounding)
|different gait pattern|
Making permanent track records
Casts of tracks can be made with plaster of Paris, which is available at hardware stores, or dental plaster which can be obtained from dental supply companies. Dental plaster hardens faster than plaster of Paris and picks up detail better. About 1 cup of plaster is needed for a wolf track. The following procedure must be done quickly, before the plaster hardens. Add water to the plaster while mixing until the mixture is the consistency of thick pancake batter, then pour it into the track, making sure to cover the entire print. If the mixture is too thick, mock details such as claws will be obscured. If it is too thin, the cast will be brittle and take a long time to dry. Gently "pat" the plaster with a stick to work it into details of the print. Leave a smooth surface on the top to record information (date, location, and collector). Allow the cast to harden for 15 to 20 minutes (5 minutes for dental plaster) before prying it out with a knife
. Tracks can also be casted in snow, but the plaster takes up to an hour to harden. There are 4 methods for casting tracks in snow. One method entails spraying the track with a fine mist of water until a coating of ice forms so that the plaster mixture will not melt through. Adding snow to the plaster mixture will cool it down and make melt-throughs less likely.
The second method uses a spray wax which can be purchased from Kinderprint Co., Inc., P.O. Box 16, Martinez, CA 94553. The track is sprayed with 2 to 3 coats of wax, allowing 1 minute between coats. A cast is then made with plaster. In subzero temperatures the track should be covered with plastic or newspaper and then covered with snow. Otherwise the water may freeze before the plaster sets up (Barbat et al. 1990).
The third method uses elemental sulfur, which may be purchased at gardening centers and drug stores. Heat and stir the sulfur in a pot until it liquefies. Do not inhale the fumes. Remove the pot from the stove and continue to stir until the mixture hardens just a little and then pour the substance into the track. It takes about 2 minutes for the cast to harden. It is difficult to make good casts in fine-grained, powdery snow with any method.
The fourth method uses silicone (which can also be used in other substrates). Silicone makes a virtually unbreakable cast but costs about $5.00 per track. Directions and materials for making silicone casts can be obtained from Sirchie Fingerprint Laboratories, Raleigh, North Carolina 27662.
The reader is encouraged to experiment with track casting under a variety of conditions before going into the field.
Photographs also form a permanent track record. A ruler or other object should be included in the photo for scale. Several photos should be taken from diffract angles, distances and F stops. Infrared film works better in snow than regular film.
Differentiating wolf howling from other canids
Wolves vocalize by howling, barking whimpering, and growling. Wolves may bark when their den is disturbed of if they are surprised at a kill. The bark is deep and sounds much like a large dog's bark.
The howl of a wolf is most described as deep and mournful. Theberge and Falls (1967:334) described it as follows: "The howl is a continuous sound from about half a second to 11 seconds in length. Most of the time, the pitch remains constant or varies smoothly, and may change direction as many as four or five times. Total intensity does not greatly vary throughout." A howling session by a single wolf lasts an average of 35 seconds, during which the animal howls several times. A howling session by a pack lasts an average of 85 seconds. It is initiated by one wolf, and after its first or second howl one or more others may join in (Joslin 1966) It is extremely difficult to assess how many wolves are howling if there are more than 3 or 4 (Harrington and Mech 1982). Fuller (1988) found that more than 80% of wolf howls were heard at 0.9 miles (1.5 km) and less, but none were heard at greater than 1.5 miles (2.5 km). This research was conducted in flat, wooded terrain.
Except for high-pitched yapping if pups are present, wolf howls almost never include barking. The howls of coyotes are higher pitched than wolf howls and usually include yapping and barking before, during, and after howling. The howling of large breeds of dogs are sometimes difficult to distinguish from wolves, but dog howls almost always include some barking and are usually associated with human activity.
Characteristics of estrous, and differentiating scats of similar species
Blood found in urination marks in January and February is indicative of a female coming into estrous. If this sign is found along with the tracks of 2 or more wolves, a strong possibility exists that breeding will occur.
Scats are runny and black after wolves have fed on fresh meat. They then gradually become firmer and more formed. Formed wolf scats usually have ungulate fur and/or bones in them. Volume is similar to a large dog's scat. Scat deposits may be many miles apart if wolves have not fed recently.
Considerable overlap exists between the size of wolf and coyote scats. Air-dried scats of 1.2 inches (30 mm) and larger in diameter are wolves 95% of the time. However, 2/3 of the time wolf scats are less than 1.2 inches (Weaver and Fritts 1979). Coyote scats often contain hair and bones of small mammals. However, this is not diagnostic as wolves also eat small mammals, and coyotes scavenge and sometimes kill ungulates.
The scats of a black bear that has been eating meat are similar to wolf scat, but with a larger volume and a different odor. Mountain lion scats are more segmented than wolf scats but are similar in size, volume and content. However, mountain lions often cover their scats with leaves, sticks and dirt.
At present there are no techniques for conclusively matching scat with the species from which it came. However, scat contains self groomed hair, and if hair identification improves, this method may work for scat identification. Additionally, some work is being conducted using thin layer and gas liquid chromatography to determine species based on chemical composition of fecal bioacids (Mark K. Johnson, Univ. Louisiana, pers. common.). This may become a viable method in the future
. Scats should be collected without touching them and placed in a sealed plastic bag and than sterilized before the contents are examined. Canid scat may contain parasites that can be harmful or fatal if ingested or inhaled. To destroy parasites, heat scat above 212°F for 15 minutes. This can be accomplished by using an autoclave or pressure cooker. WEP places each scat in an aluminum can with the top cut out, and puts these in a pressure cooker that is brought up to temperature and pressure on a Coleman stove outdoors.
Differentiating wolf kills from other predators' kills
Mech (1966 and 1970), and Roy and Dorrance (1976) describe attacks by wolves on wild ungulates and domestic livestock. Wolves typically attack the hindquarters, flanks, shoulders, nose, and tail. They feed preferentially on the viscera and hind limbs. This is not obvious if the animal is attacked by a pack, as the entire carcass is usually quickly consumed. Table Ill shows characteristics distinguishing wolf-killed animals from animals killed by coyotes, dogs, bears and cougars.
Search the area surrounding the carcass thoroughly for tracks, hair and scat.
Animals that have starved often die resting on their sternum with their legs folded under their sternum, while predator-killed animals are usually found lying on their side with legs extended.
Table III: Kill characteristics of predatory species in the Northern Rockies
| Area of
|Fringe of settlement.||State-wide.||Settled areas.||Forested areas.||Mountains and foothills.|
|Prey||Deer, elk, moose, beaver, cattle, sheep, horses, dogs.||wild ungulate, young rabbits, sheep, calves, poultry, rodents, birds.||sheep, calves, poultry.||wild ungulate, young rodents, cattle, sheep, swine.||deer, elk, rabbits, cattle, sheep.|
|Trails of blood and hair; bites on hindquarters, flanks, shoulders, nose, tail.||Sheep; bites on throat and head. Calves; bites on hindquarters and flanks.||Harassment, mutilation, bites on ears, shoulders, flanks, hindquarters, tail.||Blow to anterior, claw marks on face and shoulders, bites on head, neck and back, wounded prey common||Leaps on back and bites into neck and back vertebrae; teeth marks on upper neck, claw marks on shoulders.|
|Prefers visera and hind limbs, preferential feeding nor obvious in packs. Except for stomach contents, carcass may be entirely consumed. Especially true of young or small animals.||Enter through upper most flank, consumes visera and upper most thigh first, leaves hide in more or less one piece.||Feed lightly or not at all.||Drag prey to cover, flesh of hind limbs consumed first, skin and bones remain more or less intact. Grizzles cover prey, black bears usually do not.||Heart, lungs, liver, kidneys - then meat.|
Characteristics of wolf dens
Wolf dens are located near water and are usually dug into well- drained soil on a south-facing slope. They can be dug under a boulder, among tree roots, or in cut banks, hollow logs or other features. Wolves often enlarge coyote or fox dens. Den entrances measure about 18 inches (45 cm) in diameter and are usually large enough for a thin per- son to squeeze through. The passageway, which may be straight, forked or hooked, is 4.5 to 17.5 feet (5.3 m) long with a chamber measuring approximately 18 inches high by 48 inches wide by 41 inches deep (46 by 122 by 104 cm). No bedding is in the den. If the den has been used in the last several years, bones will be scattered about and well-defined trails should radiate from the den. It is common for dens to be reused (Ballard and Dau 1983, Stephenson 1974, Fuller 1989).
Often, other diggings are found near the den. These holes are of lesser diameter and usually do not extend inward as far as the den. Collect hair from suspected dens.
Comparison of adult coyotes and wolf pups.
Wolf pups vary greatly in graph rate and size (Van Ballenberghe and Mech 1975). In August, pups weigh about 40 Ibs (18 kg), about the weight of a healthy coyote, but by the beginning of July they are usually taller than coyotes. They are also distinguishable from coyotes by their puppyish features---feet "too big" for their bodies, legs "too long", blunt nose, and shorter, less bushy tail. Wolf pups have nearly adult-sized feet by late July.