Research scientists have verified evidence of hybridization between wild Canada lynx and bobcats in Maine through DNA analysis. Hair and tissue samples collected by wildlife biologists from two cats were tested at the U.S.D.A. Forest Services genetics laboratory in Missoula, Mont., confirming that the animals - one male and one female - were lynx-bobcat hybrids. The DNA tests further revealed that each was the offspring of a female lynx and a male bobcat.
"We suspected that these two cats were hybrids," said Maine Department of Inland Fisheries and Wildlife biologist Jennifer Vashon. "While they more closely resembled bobcats, each had physical features consistent with lynx such as long ear tufts or an almost completely black-tipped tail."
The Canada lynx is protected by the Endangered Species Act as a threatened species in 14 of the lower 48 states, the southern part of its historic range. Hybrid lynx-bobcats, however, are not protected by the federal law.
Wildlife biologists with the Maine D.I.F.W. and the U.S. Fish and Wildlife Service have jointly studied Canada lynx in northwestern Maine for the past five years to learn more about the status of the population in the state.
"The DNA evidence in large part indicates that lynx and bobcat populations in Maine remain genetically separate," said Service biologist Dr. John Organ. "We cant predict at this time what, if any, long term effects hybridization will have on the lynx population. In the meantime, well continue studying lynx as part of our ongoing efforts to conserve the species in the Northeast."
"In addition to identifying the hybrids we ran DNA tests on samples from another 29 individual lynx from Maine and found no further evidence of hybridization," said Dr. Michael Schwartz, the U.S.D.A. Forest Service wildlife ecologist who heads the genetics laboratory where the hybrid test was designed. "It should be noted, however, that hybrids are just as likely to be classified as bobcats and we have not examined many bobcat samples from Maine."
"We were not surprised that the 29 lynx samples from our northern Maine study area were determined to be pure lynx as there are few bobcats in that portion of the state," said Vashon.
"However, the locations where the two hybrids were found are in the region where both lynx and bobcat occur in Maine, and I expect the likelihood of hybridization would be greater."
The male lynx-bobcat hybrid was trapped in 1998. The trapper, concerned that the animal could be a lynx, contacted Maine wildlife officials to evaluate the animal. The animal was radio-collared and released. It died several months later apparently of starvation.
A graduate student from the University of Maine conducting research in the fall of 2002 first located the female hybrid, which was held in a trap. She observed one kitten in a nearby tree and two kittens walking near the trapped cat. Department biologists examined the animal, and, suspecting that it was a lynx-bobcat hybrid, collected samples for DNA analysis.
"Now that we have proof that the female was a lynx-bobcat mix, the presence of kittens indicates that the hybrid animals can reproduce," said Organ. He explained that the offspring of hybrids of other mammals, such as wolf-dog or donkey-horse hybrids, can be either sterile or fertile.
Canada lynx-bobcat hybrids were first scientifically documented earlier this year in Minnesota, when researchers at the U.S.D.A. Forest Service genetics laboratory in Missoula confirmed through DNA analysis that samples from two cats exhibiting characteristics of both species, and a hair sample sent in from a third, were from lynx-bobcat hybrids. It could not be determined at that time if the hybrids could reproduce.
Service and Maine D.I.F.W. wildlife biologists first confirmed the presence of a resident population of Canada lynx in Maine in June 1999 when they found a den with two kittens. To date, they have studied 23 litters totaling 63 kittens, and have captured and marked 93 lynx, including 32 radio-collared adult and sub-adult animals and 61 kittens.
The biologists this spring documented six dens containing nearly double the number of kittens found in previous years. Four of the litters, each numbering five kittens, were the largest the biologists have found in the state.
The ranges of lynx and bobcats overlap in Maine. Unlike the bobcat, lynx are highly adapted to live in areas where there is deep snow, isolating the two species in the winter. While they are closely related, the two species are genetically distinct.
Canada lynx are medium-sized wild cats that live in the extreme northern forests of North America. Canada lynx have large paws that function like snowshoes, allowing them to hunt in deep snow. The cats feed primarily on snowshoe hare and other small mammals and birds. The lynxs range extends from Alaska, throughout much of Canada, to the southern boreal and transitional forests in the northeastern United States, the Great Lakes, the Rocky Mountains and the Cascade Mountains. With the exception of Maine, it is believed that lynx populations have been extirpated in the northeast.
Bobcats are also medium-sized wildcats whose range extends throughout most of the lower-48 states and into southern Canada. They do not occur in Alaska. Bobcats are similar in appearance to lynx, but their feet and ear tufts are noticeably smaller, and their tail is whitish below and at the tip, with a black band around the tip. Lynx have no white markings on the tip of their tail. Bobcats are generally more reddish in color than lynx, and may have more distinctive dark spotting on their fur. Bobcats feed on a variety of rabbit species, rodents, other mammals, and birds. While lynx feed primarily on snowshoe hare and will prey on other species when hares are not abundant, bobcats feed on a broader array of prey species.
The U.S. Fish and Wildlife Service is the principal federal agency responsible for conserving, protecting and enhancing fish, wildlife and plants and their habitats for the continuing benefit of the American people. The Service manages the 95-million-acre National Wildlife Refuge System which encompasses nearly 540 national wildlife refuges, thousands of small wetlands and other special management areas. It also operates 66 national fish hatcheries, 64 fishery resource offices and 78 ecological services field stations. The agency enforces federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign governments with their conservation efforts. It also oversees the Federal Aid program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state fish and wildlife agencies.
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Dr. John Organ, U.S. Fish and Wildlife Service, 413/253-8501
Jennifer Vashon, Maine Department of Inland Fisheries and Wildlife 207/941-4238
Dr. Michael Schwartz, U.S. Forest Service, Rocky Mountain Research Station, 406/542-4161
