Thursday, September 17, 2020

Evolution of the Canadian Lynx and the American Bobcat

The Eurasian Lynx entered North America across the Bering Land Bridge about 2.5 million years ago, in the first of two waves. Glaciers waxed and waned, alternately blocking and opening Beringia, as well as migration paths down to what would become the U.S. border and Canadian province areas, a classic example of how one species gets separated by changing land and sea features, the two groups then evolving in different directions, until representatives of one group can no longer mate, thus resulting in two species. The second wave, coming with melting of northern glaciers evolved into the Canadian Lynx.

Lynx characteristics

The Canadian Lynx is smaller than the Eurasian Lynx, but slightly taller than the bobcat. What is most interesting in these developments is that Canadian Lynx not only evolved into specialty predators, largely dependent on snowshoe hare, but if you leave out the skulls of the lynx and hare, at first glance, their skeletal structures appear similar, almost like a marriage where one was literally evolved to chase the other. The wonders of natural selection and evolution. 

On the other hand, it also means that Canadian lynx populations are almost entirely dependent on the populations of snowshoe hare, not exactly a good place to be, in a world where the addition of competition from other predators, like bobcats, human hunters and trappers, as well as climate change may cause havoc with the availability of various wildlife populations. There are examples of hybridization between lynx and bobcats, and you will meet both bobcats and a Eurasian Lynx when you visit the Adirondack Wildlife Refuge.

What sets them apart visually: Lynx have longer legs, longer rear feet than bobcat, and their hips are consequently higher than their shoulders. Lynx have stubbier, black tipped tails, much broader paws, and with both species, the front paw is broader than the rear.

Bobcat characteristics

The bobcat is a uniquely North American cat, with most concentrated inside U.S borders. It is more of a generalist as a predator, as is the Eurasian lynx. When climate change leads to a narrower date range of regional snowfall, and less depth accumulation overall, lynx move further north and to higher elevations, a trend observed in British Columbia and Ontario. 

A declining snowshoe hare population results in fewer Canadian lynx, while the bobcat, hunting smaller animals like mice, squirrels, rabbits, possums, and birds, in shallower snow, moves in. Concentrating on smaller prey causes a gradual adjustment downward in bobcat size, which may explain why the bobcat is shorter than the Eurasian lynx, and why, by 20,000 years ago, bobcats had assumed their current size and appearance.

About twice the size of domestic cats, adult male bobcats range from 14 to 40 lbs, females from 8 to 32 lbs. From nose to bobbed tail, bobcats are 19 to 50 inches, and stand 12 to 24 inches at the shoulder. Following Bergman’s Rule, bobcats in colder northerly climates are larger on average than their more southerly counterparts, as larger animals retain body heat better than smaller ones, and therefore are more likely to live to breed, and pass along that larger size. Lynx are slightly taller, but not always heavier, and have specialty features like fur covering the pads of their broader, snowshoe like paws to help in heat retention.

Bobcats have prominent white spots bordered by black on the back of their ears and on the underside of their six inch bobbed tail, making it easier for kittens to follow mom. Their ears are not as tufted as lynx ears, which in both cases may aid in directing sound to the ears, and in conjunction with ruff whiskers, make it easier to detect brush and other landscape features they are moving through. Their broad paws serve as snowshoes, while the webbed toes aid in swimming, and have retractable claws. The four toed foot prints are easily identified, as they’ll be larger than cat prints, but lack the claw marks of canids. 

Camouflage is naturally an important aspect of appearance. Bobcat coats are brownish, tawny, beige, with darker colors indicating bobcats which live in darker habitat like forest and heavy understory, as opposed to the lighter colors of desert and plains habitat. Their underside is whitish. Horizontal blotches shaded by the gradually lightening coat grow more distinct down the flanks and legs morphing into darker, more defined spots. Lynx have grayer coats with less defined spotting.

Bobcats’ hunting, mating habits

Bobcats live in a wide variety of habitats, which must contain not only prey, but access to females, as well as spread out temporary shelters, under rocks, in log hollows, caves or brush piles. when returning to the den from a great distance is not practical. Bobcat territory sizes vary by region, and may expand with seasons in which prey is not as abundant, as when some Summer prey is hibernating. All else being equal, which it never is, male territories average about 8 square miles, and may overlap female territories. Bobcats scent mark their territories assiduously, spraying, scraping, clawing trees and rubbing with anal glands. Bobcats probably move an average of 4 miles per day, and are predominantly crepuscular in their hunting behavior.

While bobcats generally prey on smaller animals, lean times may cause them to take greater risks, and go after larger, more challenging prey like fawns, fox, female fishers, swans, domestic cat, small dogs. Curiously enough male fishers have more success killing lynx than the bobcat, who often turns the tables on the aggressive fisher. Bobcats are the main predator of the whooping crane. 

Bobcats are basically ambush and pounce predators, sneaking up on prey, or waiting for prey to pass by. The most important sensory input is their sharp eyesight, probably followed by what they hear, and finally what they can smell. Bobcats are great climbers, but reluctant though competent swimmers. Bobcats have a wide range of vocalizations, including scowling, snarling, spitting and screaming during mating season. Prey which is not entirely eaten will be cached, and visited again and again.

Mating takes place between February and March, with a litter of one to four kittens born in a vegetation lined den about 60 days later. Mom nurses the kittens for about two months, and they stay with her, learning how to hunt, sometimes through the first winter. Male bobcats play no role in rearing the kittens. Female kittens can mate at one, but usually wait until they are two. Males can mate at two. Bobcats live an average of 10 to 12 years in the wild, sometimes twice that in captivity.

Top photo: A bobcat with a chipmunk, by Joe Kostoss, of “Eye in the Park.” Eurasian Lynx photo by Steve Hall. Second bobcat photo by Kevin MacKenzie. All images courtesy of Adirondack Wildlife Refuge.

 

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Steve Hall

Steve and Wendy Hall run the Adirondack Wildlife Refuge and Rehab Center in Wilmington. They've been rehabbing and releasing wild animals for over 45 years, specialize in predators, keep wolves as the cornerstone of their educational program, and have lived in the Adirondacks for the past 20 years. The Adirondack Wildlife Refuge became a non-profit about 10 years ago.

Visit www.AdirondackWildlife.org to learn more.


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7 Responses

  1. Boreas says:

    Another great article Steve! I only wish I had a bobcat that would frequent my property. I have plenty of chipmunks and squirrels!

  2. ADKresident says:

    A good read!! 👍

  3. Marlene Barton says:

    We saw a Lynx on the back side of Gore Mountain a few years ago which was awesome. Great article.

  4. AG says:

    Eurasian lynx are so much bigger than Canadian Lynx and American bobcats. It’s strange how they changed in the Americas..

    • Eurasian Lynx hunt Roe Deer in Asia, about half the size of our white-tails. When they arrived in North America, natural selection adopted their size over thousands of years to exploit smaller available prey. Both predator and prey have to develop the right characteristics to survive and breed. Many examples in nature.

  5. Philip Terrie Phil Terrie says:

    Interesting! What happened to the first wave of Eurasian lynx? I think you said above that it was the only the lynx in the 2nd wave that evolved into the Canadian lynx. How long ago did this 2nd wave occur?

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