Lynx canadensis - Canadian Lynx

Skull Pictures:     
Dorsal       Posterior mandible
Lateral      Ventral
Mandible

Physical Description:

The average total length of an adult Canadian lynx (Lynx canadensis) is between 875-1,000mm; tail 100 to 120mm; hind foot 215 to 250mm.  The average weight of an adult lynx is 7-16kg.  Males are typically five percent larger than females.  Older individuals tend to develop a more pronounced saggital ridge (Jackson 1961).

The lynx is a mid-sized felid with a short tail and broad paws.  Its thick dorsal fur is commonly yellowish brown, sometimes with a frosted gray appearance.  The fur has variable spots, usually occurring on the sides and legs.  Its most distinctive feature is the black tufts of hairs on the ears that are as long as 50% of the height of the pinna; ruffs are also present below the jaws and on the cheeks.  The only Wisconsin mammal that a lynx could reasonably be confused with is the bobcat (Felis rufus).  However, the bobcat has a longer tail and the tail is not black all around as it is in the lynx.  Other differences are the shorter ear tufts in the bobcat and smaller feet (Kurta 1995).

Distribution in Wisconsin:

Declared an endangered species in 1972 by the state, the lynx’s distribution in Wisconsin is not well known.   The lynx has never been all that common in the state.  The fur was highly desirable, yet only a few pelts were sold each year in Wisconsin in the early 19th century (Jackson 1961).

Since 1870 there have only been 28 verified records of lynx in Wisconsin, occurring most frequently in the northern portion of the state.  Between 1962 and 1973 16 lynx were killed in the state; that is half of all the records from 1870 to the present.  A similar rise of mortalities during this time period also occurred in Minnesota, North Dakota and Montana, the reason is unknown.  Since that time only two more lynx have been found in Wisconsin, both in 1992 in Bunette and St. Croix Counties, these lynx are both a part of the University of Wisconsin-Stevens Point mammal collection (McKelvey 1999).  A breeding population has never been discovered and it is believed that most occurrences are drifters coming through Michigan or Minnesota from Canada.  In fact in 1997 the lynx was removed from the state’s endangered species list as it has not been a recent or current breeder.  In 1998 it was added to the states list of protected animals.

Ontogeny and Reproduction:

Lynx mate in January or February followed by a gestation period of roughly 62 days.  The mother makes a nest in a hollow tree, stump, log or brush pile by pawing together leaves and bark.  The kittens are born with their eyes closed for the first ten days of life.  They are browner than the adults with dark spots that disappear by about nine months of age (Jackson 1961).  It is unclear whether female lynx are induced or spontaneous ovulators.  Lynx generally have one to four young.  The number per liter is closely tied to the snowshoe hare abundance, for reasons discussed in the following section (Mowat 1999).  The kittens remain dependant on their mothers for milk for four to six months, but began to consume prey killed by her after one month (Kurta 1995).

Ecology and Behavior:

The lynx is generally a solitary animal, the males and females avoiding each other except to mate.  A lynx usually inhabits a home range of 10-50km2.    The boundaries are marked with urine and feces and the territories respected by both sexes.  The lynx is a predominately nocturnal hunter, spending its days under down trees or rock overhangs.  Its preferred habitat is a mature coniferous forest (cedar swamps and upland forests of hemlock and fir) with thick litter and rotting logs, this is also the preferred habitat of snowshoe hares (Kurta 1995).

The lynx follows a much studied population cycle with its number one prey species the snowshoe hare (Lepus americanus).  The lynx parallels, fairly rigidly, an up and down population cycle of ten years with the snowshoe.  The connection between lynx and hares is one often referred to as an example of population dynamics and predator/ prey relationships in courses covering the subjects across the country.  It goes so deep that female lynx actually have less or no kittens when hare abundance is down, and more kittens when the population is on the rise (Mowat 1999).

When snowshoe populations are down the lynx begins to depend more and more on its other prey such: red squirrels, mice, voles, flying squirrels, ground squirrels and grouse.  The lynx occasionally prey on white tailed deer, usually fawns or rarely adults in deep snow (Mowat 1999).  The lynx also kills red fox when it has a chance because it is viewed as a natural enemy and because of competition for food.

Lynx are not fast runners and so depend on stealth to catch their prey.    They hunt by either stalking and rushing their prey or waiting along a trail and ambushing it.  The lynx prefers freshly killed prey and only seldom caches a kill for later.  The lynx’s large padded feet act like snowshoes in winter; spreading their weight out over a large surface area so they can walk on top of deep snow instead of in it.  This gives them an advantage over most of their prey species and keeps them on a level playing field with snowshoe hares.

The lynx largest enemy is man.  Before protection the lynx was a valuable pelt the few times it was successfully killed in Wisconsin; from 1865 through 1957 there was a state financed bounty placed on the lynx in Wisconsin.  However, even more detrimental is the habitat destruction caused by humans; clear-cutting and plantations of red pines are not suitable for lynx.  The lynx is also affected by external parasites such as Ceratophlyuss denatus and C. labiatus and internal parasites such as Taenia laticollic and T. rileyi (Jackson 1961).  Due to the historical low numbers of lynx in Wisconsin, the endangered species act as it pertains to the lynx is a controversial issue.  One side wants the protection of possible lynx habitat, even though there is no proof of their existence in the area.  The other side of the coin does not want the complete protection called for in the endangered species act for a mammal that has never had a significant population in the state because it jeopardizes human interests such as logging and recreational uses (note as stated before the lynx is not currently listed as an endangered species in Wisconsin, but as a protected species).  The issue of listing the lynx is even more heated in Minnesota and western states where more lynx are present.  The most famous being the falsification of lynx DNA in Gifford Pinchot National Forest and Wenatchee National Forest in Washington to prove that lynx inhabited the area and it deserved protection.  It was later found the DNA was from captive lynx and the biologists responsible for the hoax claim to have been testing the ability of the laboratory to correctly identify lynx and were not attempting to falsely increase the range of the lynx (Pierce 2001).  

Literature Cited:

Jackson, H.T.  1961.  Mammals of Wisconsin.  The University of Wisconsin Press, Madison, 395-400.

Kurta, A.  1995.  Mammals of the Great Lakes Region.  University of Michigan Press, Ann Arbor, 252-254.

McKelvey, K.S., K.B. Aubry, and Y.K. Ortega.  1999.  History and Distribution of Lynx in the Contiguous United States.  RMRS-GTR-30WWW-Ecology and Conservation of Lynx in the United States.  Hard copy published by the University of Colorado, 207-253.

Mowat, G., K.G. Poole and M. O’Donoghue.  1999.  Ecology of Lynx in Northern Canada and Alaska.  RMRS-GTR-30WWW-Ecology and Conservation of Lynx in the United States.  Hard copy published by the University of Colorado, 265-298.

Pierce, J., T. Quinn and J. Scott.  2001.  Statement from Washington Department of Fish and Wildlife Chief Scientists Regarding the Submittal of False Data for Interagency Lynx Study. <http://www.forwolves.org/ralph/lynx-false-wash-state.htm>.
 

Reference written by Jason Schmidt, Biol 378: Edited by Chris Yahnke. Page last updated 4-27-04.