Running With The Wolves
Wolf Information & Awareness Center
"Wolf Anatomy"
Article by Wolf Howl Organization

Wolves are covered in a moderate length pelt across most of their body. The color of their fur may range from pure black to pure white, with any tint or shade of gray, tan, cream, ochre (yellow-gold), sienna (reddish brown), and brown between. On Wolves having light and dark patterned fur, the markings tend to be lighter on the ventral (belly) side of the body and graduate to darker/longer/thicker fur on the dorsal (back) side.

The ears, forehead, and top of the muzzle are usually of a short/course/lighter fur, mingled of dark and/or mid pelage tones with the underside of the muzzle and throat being of lighter pelage tones. The legs and paws also have short/course/ lighter fur. The tail is generally covered with a long/thick/bushy fur, the color scheme being similar to that of the rest of the Wolf; dark on top and lighter on the bottom. Light colored Wolves may even have a dark spot of fur covering the precaudal scent gland, also called the violet gland, at the top of their tail, about 10 cm (4 inches) from its base and on the tip.

Although little research has been done into a Wolf's ability to see color, it is believed that they may be partially color blind. Wolves have only red and blue photo receptors in their eyes, unlike humans, who have red, green, and blue photo receptors. Tests on domestic canines show that they may not be able to distinguish yellow from green or orange from red. Tests on Wolves, where red, blue, yellow, and green dyes were put onto clean snow, show that they often detect the red and yellow stains. This could be because they associate these colors with blood and urine and have little interest in the other colors. There is no conclusive evidence regarding the color vision abilities of Wolves, however. It is my personal belief that Wolves can see all of the colors, but only take an interest in those that might benefit them in some way.
Canines have a third eyelid (nictitans) which stretches across the eye and contains a gland which, along with glands in the ciliary body, acts to lubricate the eye. However, these tear glands excrete an oily substance rather than watery tears: Canines are not able to shed the moist tears of sorrow as humans do, but this doesn't mean they don't cry.

The sense of smell is a Wolf's most developed sense and greatest asset. A domestic canine's nasal cavity has about twenty-five times the number of olfactory receptors and fourteen times the scent receptive surface area of a human being. It has been suggested by experts that a Wolf may have twelve times the ability to detect odors of a domestic canine and a hundred times that ability of a human being.
The sense of smell plays a very important role in lupine life and society. Not only is it the means by which Wolves detect and locate pray, but it is instrumental in a variety of other tasks. A Wolf's body has scent glands (see the Scent Glands section) that tell a Wolf's health, mood, and identity to other Wolves. Upon meeting, Wolves will smell each other's muzzle, anus, and tail to make sure they know who the other Wolf is, and also learn details about health, mood, where the Wolf has been, and what she/he has been eating. Wolves use urination, called marking, to mark their territories so other Wolves may know they are crossing into another pack's land by smelling the marks.
A Wolf's tongue is long and quite soft. It is covered in hundreds of projections called papillae which aid in grooming and with tugging meat from bones. A Wolf also uses the tongue for licking up blood, drinking water, and during certain social rituals where tongue contact indicates respect and/or submissive behavior. The tongue is quite thick, but tapers to a thin tip that can be curved into a ladle-like form, making it especially useful for lapping up water.
It's difficult to know exactly what another animal is able to taste, but it is known that canines have taste receptors that permit them to know the sensations of sweet, salty, bitter, and acidic.

As with other canines, Wolves are digitigrade; meaning they bear their weight on their toes as they walk and not the entire sole of the foot. There are four toes on each hind paw, and five toes on each forepaw. However, one of the toes on the forepaw is used for clasping and doesn't touch the ground. Each toe has a calloused pad and a non-retractable claw. Also, each paw has a single large calloused heel pad. An adult Wolf's forepaw prints measure from about 11.4 to centimeters 12.7 (4� to 5 inches) in length and from about 9.5 to 11.4 centimeters (3� to 4� inches) in width, with their hind paws measuring 15 to 20% smaller then their forepaws.
As average gait of a Wolf is between 6.5 and 8 kilometers (4 and 5 miles) per hour. Wolves can maintain an average top speed of about 40 kilometers (25 miles) per hour over a distance of 3 kilometers (2 miles). A Wolf maintaining a speed of 56 kilometers (35 miles) per hour over 6 kilometers (4 miles) was reported by a Minnesota game warden in 1955. There have been other reports of Wolves running in excess of 56 kilometers (35 miles) miles per hour, but these are likely exceptional extremes. Wolves bound when they are in pursuit of large prey animals. L. David Mech reported that he witnessed Wolves bounding over 5 meters (16 feet) while in pursuit of moose. Wolves can keep up the chase for about twenty minutes, after which they tend to rest or sleep for at least ten to fifteen minutes before resuming activity.
It's not uncommon for a Wolf to travel 32 to 48 kilometers (20 to 30 miles) a day while hunting. Where food is scare Wolves have been recorded to have walked 190 kilometers (120 miles) searching for food in a single day. Wolves have a great capacity for long journeys. When dispersing from their pack, lone Wolves have been monitored traveling over 800 miles in search of new territory

The male genitalia consist of a fur covered scrotum, composed of thin, dark colored skin. The scrotum surrounds the testicles and is designed to keep the testicles several degrees cooler than the Wolf's internal body temperature so that the sperm are not damaged by excessive warmth. From the scrotum extending along the lower belly is the prepuce, often called the sheath. The prepuce is a flap of fur covered flesh that sheaths and protects the penis. The penis is a soft fleshy organ which extends from the sheath as it pumps full of blood when the Wolf becomes sexually aroused. The penis contains a bone called the Baculum Bacula (OS penis), which aids in penetrating the female's vulva during copulation. When canines mate the male's erection occurs after penetration, rather then before (to achieve) penetration as in humans.  Toward the base of the penis is the bulbus glandis, also called the knot, which swells into the female's vagina to tie the male and female together during coitus. The knot prevents the mating pair from parting until after insemination has taken place. In addition to mating function and urination, the penis is also used to scent mark; it is believed that the urine contains a pheromone, or scent, unique to the individual Wolf and that other Wolves smelling this mark can easily identify the Wolf from whom it came from. Out of mating season a male Wolf's testicles tend to shrink, accompanied by the loss of sexual appetite.

The female genitalia are mostly internal. The external labium (lips) of the vulva occupies approximately the same physical location on the body as the scrotum would on a male. In the wintertime, when the female enters estrus, the vulva becomes hot and puffy (hence the term "in heat"). This puffy/swelling makes the female visually interesting to males, and along with the pheromones produced in the vagina, indicates when the bitch is physically ready to mate. The puffy vulva is also ideally shaped so that the tip of the male's penis can easily hook into its fold to be directed into the vagina during copulation. During copulation the male thrusts his penis into and out of the female's vagina while shifting his weight from one leg to the other in order to work his bulbus glandis into her. This locks the male's penis into the female's cervix, which undulates to stimulate his penis to erection. Erection expands the bulbus glandis and ties the two Wolves together; thus coitus is achieved.

Once coitus is achieved, the female's vaginal sphincter muscles tighten around the male's bulbus glandis to hold it firm as she pulls forward, triggering ejaculation of semen into the uterus. In the initial 30-50 seconds of the tie, the male deposits only clear semen until orgasm is achieved. During the initial 30 seconds or so of orgasm, a cloudy, somewhat thicker, sperm bearing semen is ejaculated; thus insemination is achieved. After insemination the semen returns to a clear state, but continues to pump forth until the end of the tie, which may last up to 35 minutes. Additional information about courtship and mating can be found in the procreation section. 

A Wolf's tail measures from 33 to 51 cm (13 to 20 inches) and consists of long fur radiating away from it in all directions, but sloping toward the tip. Most Wolves have a dark spot of fur covering the precaudal scent gland, also called the violet gland, about 10 cm (4 inches) from the croup and on the tail's tip. The tail serves to protect the anus and genitals from insect bites as well as a device for communicating with other Wolves. The communications aspect of the Wolf's tail will be delved into in the section dealing with communication.