Cougars: On the Trail of the Ghost Cat
Researchers studying the elusive movements of cougars are learning that the cats' behavior may reflect changes in their habitat
IN PRICKLY UNDERBRUSH ON THE NORTH RIM of Arizona’s Grand Canyon, Brandon Holton and his Australian-shepherd-mix dog Gus were looking for bodies—the remains of deer and other prey that cougars leave behind. A U.S. National Park Service wildlife biologist, Holton can tell much from the cats’ kill sites, from which prey they are eating and the health of the animals they consume to where the cats travel and how they behave.
Since 2003, the service has monitored more than 30 cougars in Grand Canyon National Park using infrared cameras and collars that transmit the cats’ global positioning system (GPS) locations from satellites to Holton’s inbox daily. If a cat stays in one location for days, Holton knows it has made a kill, and he will soon be scrambling up and down mountainsides to find what it has left behind. “It takes time to get into the mind of a cougar,” says Holton. “But that’s the fun part.”
Holton is partnering with U.S. Geological Survey wildlife biologist David Mattson, who is compiling data from several studies, gathered from hundreds of thousands of GPS satellite and radiotelemetry signals from collared mule deer, bighorn sheep, elk and more than 100 cougars in the areas of the Colorado Plateau straddling Arizona, Colorado and Utah. This is the first attempt to record cougar movements in real time on such an expansive scale, Mattson says. “We are trying to predict where they will be—the ways they orient themselves to the landscape as the environment changes.”
Human infrastructure is fragmenting cougar habitat, climate change is altering ecosystems and, in some cases, the cat’s prey has moved, increased or declined. Infrared cameras, satellites and genetic analyses are allowing scientists to slowly piece together where these elusive predators travel in this fluctuating world and what such sometimes surprising discoveries could mean for the survival of the United States’s largest wild cat.
Whether called a ghost cat, catamount, mountain lion or cougar, Puma concolor has the greatest range of any terrestrial carnivore in the Western Hemisphere. These cats inhabit western Canada, Central and South America, much of the western United States and southern Florida. They are active year-round in all types of terrain, from snowy alpines and dense forests to rocky deserts and muggy swamps. Though the cats once roamed throughout North America, unregulated killing and government-sponsored bounty hunts depleted the U.S. cougar population by the early 1900s, and with the exception of endangered Florida panthers (P. c. coryi), nearly eliminated them east of the Mississippi River. The U.S. Fish and Wildlife Service finally declared the eastern cougar (P. c. couguar) extinct in March 2011.
Which is why the phone call geneticist Michael Schwartz received three months later saying that a vehicle had killed a cougar on a Connecticut road was so shocking. As director of the U.S. Forest Service’s Rocky Mountain Research Station genetics laboratory in Montana, Schwartz gets requests from wildlife managers to identify dozens of species and estimate wildlife populations from DNA samples. Since 1999, he has accumulated a database of more than 1,000 individual cougars, but never one from so far east.
Wildlife experts determined the 3-year-old male was wild because he had porcupine quills under his skin and was not neutered or declawed. Speculation ensued whether he could be one of the long-lost eastern cougars. However, comparing the cat’s DNA with other samples on file, Schwartz’s team determined that since 2009, this cougar had wandered from its home in South Dakota through Minnesota, Wisconsin (as captured by a camera trap, left) and New York before it was seen in a Connecticut schoolyard and finally killed on a road—an epic journey of about 1,500 miles. “It was really like a detective story,” says Schwartz. “We learned each piece one at time.”
Reports have confirmed individual cougars crossing hundreds of miles in attempts to find mates or establish new territories, but none have traveled as far as this male. University of Minnesota wildlife ecologist Michelle LaRue and her colleagues recently reported that between 1990 and 2008, 178 pieces of evidence of cougars—photos, video, tracks or DNA samples—had been found in 14 midwestern U.S. states and two Canadian provinces where they had been previously extirpated.
What is needed to establish a new population, however, is a female leaving her home range, a male able to mate with her and resulting cubs to survive. Most females stay within their home ranges of less than 100 square miles to be near den sites, whereas males can roam more than 200 square miles. Many of the cougars actually seen in the Midwest have been killed by vehicles or shot.
In the last three decades, researchers have found breeding cougar populations in South Dakota’s Black Hills, North Dakota’s Badlands and northwestern Nebraska. Using scat-detector dogs, Sam Wilson of Nebraska’s Game and Parks Commission is keeping tabs on the two dozen or so cougars estimated to be established in his state. Scat is collected and sent to Schwartz’s lab for genetic identification. As to whether Nebraskans mind their new residents, Wilson says, “There are strong opinions on both sides, but some people are excited about it.”
Guess Who’s Coming to Dinner?
The Grand Canyon is a microcosm of how cougar movement and behavior may reflect changes in the environment. The North Rim’s dense mixed conifer forest with steep, rocky hillsides that climb up to 8,000 feet is “perfect puma habitat,” says Holton. “Pumas need cover for hunting. They are ambush predators.”
At the kill site of a 6-year-old female cougar, a bush was about 10 feet away, and a trail of flattened grass led to where the cat had dragged a deer. Holton peered down at what little was left of the deer’s skeleton—a skull, a spine and leg bones—lying at the bottom of the dry ravine. Breaking open a leg bone, he exposed the yellow, fatty marrow inside, an indication the deer was healthy.
Typical of females, this cat stayed here for a few days, burying and reburying her stash, to preserve and completely eat the deer. Since Holton and Mattson began following the cats, they have found that females are “energy maximizers,” killing mostly smaller prey, such as mule deer, boarlike javelinas and other carnivores, and consuming most of the carcasses. Males are “time minimizers,” targeting larger prey (mainly elk on the South Rim), killing less frequently and eating choice parts of their prey to be able to move on quickly. Only a few cats are going after bighorns that live on the canyon’s floor.
This wasn’t always the case. In 1913, Arizona brought in 83 Rocky Mountain elk from Yellowstone National Park to replace the state’s extirpated Merriam’s elk. Since the 1960s, Mattson says, dams and water catchments ranchers built for livestock have allowed elk to expand to areas in the state where they weren’t before. Now more than 35,000 elk are estimated to be in Arizona, and some have moved into the southern end of the park. “This was primarily a two-prey system, bighorn sheep and mule deer,” explains Holton. “Now almost 70 percent of mountain lion kills on the South Rim are elk.” In addition, javelinas used to live in south-central Arizona, but during recent hotter, drier years, have moved north into the park and become another source of prey for the cougars.
What such changes mean for the canyon’s ecosystem is still being determined, but Holton says, “When you get rid of a native arrangement of species, things typically degrade.” Elk consume and demolish the grasses and scrub brush mule deer prefer. The researchers have also documented that more older male cougars live on the South Rim than on the North Rim.
The City Cat and the Country Cat
Even though the Grand Canyon has more than a million acres, its cougars mostly live along the rim, and those that step out of park boundaries can be legally hunted. Research suggests that the long-term survival of cougar populations may depend on whether they have wildlife corridors to connect populations and habitat. Schwartz’s database is showing that many cougar populations in the West are exchanging genes. Other populations are surviving in genetic islands, living between dangerous open areas, roads or development.
For more than a decade, National Park Service wildlife ecologists Seth Riley and Jeff Sikich have been tracking 26 cougars and other carnivores living in California’s Santa Monica Mountains National Recreation Area, a 150,000-acre park abutting western Los Angeles. Highway U.S. 101 and Interstate 405 cut off most of the cats’ interactions with other cougars and limit their access to prey. Since 2004, vehicles have killed seven cougars. Because the young males can’t expand their territories, some are killing other cats and have even mated with their own female offspring. University of California genetics labs in Davis and Los Angeles determined that “our mountain lions had reduced genetic diversity compared to others in the state,” says Riley. “Not a good thing.”
Recently, one male cougar crossed Highway U.S. 101, mated with Santa Monica females and sired at least three litters. “He potentially saved the population genetically,” says Riley. But the fix may only be temporary. “The Santa Monica Mountains are not large enough to support a viable [cougar] population. It is critical to have connectivity to the north,” Sikich says. “These animals are trapped.”
Florida’s endangered panthers have experienced the consequences of impaired genetic flow between populations. Surrounding highways and development prevent most of the cats from expanding beyond their range in Florida’s southwest corner, below the Caloosahatchee River. In the early 1990s, researchers found that the remaining 30 or so panthers had very low genetic diversity, and many had signs of inbreeding, including holes in their hearts and an impaired ability to reproduce. Some scientists also attribute the occasional bent or curled tail and cowlick on the back to inbreeding.
In 1995, to prevent a genetic bottleneck leading to the cats’ extinction, state and federal officials worked together to obtain eight female cougars from Texas and bring them to Florida to breed with the panthers. The 20 kittens later born infused the population with new genes, and the detrimental mutations declined significantly. Today, an estimated 100 to 160 panthers exist.
Yet vehicles kill a significant number of these endangered animals each year, including at least 16 in 2012. NWF and its state affiliate the Florida Wildlife Federation (FWF) have helped raise funds to build highway underpasses that panthers and many other animals use. FWF also has been working with private landowners to enhance their properties for wildlife, as ranches and farms can provide important links between public conservation lands and additional panther habitat. FWF’s Southwest Florida Field Representative Nancy Payton says such collaborations are key to the panther’s survival: “Without those private agricultural lands, the panther is not going to make it.”
The Cougar’s Uncertain Path
A changing environment may affect where cougars go. Mattson says wildlife and city managers could use the map of cougar and prey movements that he and his fellow researchers are creating to better anticipate the travels of these native predators and incorporate ways to coexist with them, such as installing highway underpasses or overpasses.
Riley recommends that local law enforcement be prepared to handle a surprise cougar visit. Santa Monica Recreation Area is a patchwork of lands managed by the park service as well as other public and private agencies. Although Riley says, “We’ve never had these lions behave aggressively toward people,” last year Santa Monica police shot and killed a male near a city boundary before Sikich could arrive at the scene. Riley says, “Agencies are not thinking about potential conflicts.”
“Lions are clearly expanding right now. They may make up our minds for us,” Wilson says. To reestablish cougar populations in the East would take awhile, however, says Schwartz: “Recolonization of cougars is like dense smoke filling a room. It takes time.”
In the Grand Canyon, at the last kill site of the day, Holton and Gus ascended a large hill and looked down at a cluster of four 60-foot-tall pines with a circle of flattened grass underneath. As they approached the trees, the fairly fresh remains of the male cat’s meal came into view, and a sweet-sour smell of digested grass and rotten venison permeated the air. “He must have ambushed the deer as it was bedded down,” Holton surmised. The hill behind the biologist would make a good vantage point for a cougar. However, after careful surveillance, Holton finished his assessment, packed up his gear and was back on the trail without the appearance of a ghost cat.
NWF Priority: Providing Pumas Habitat and Safe Passage
So that panthers and other wildlife can safely roam southwest Florida’s vast network of public and private conservation lands, NWF, its affiliate the Florida Wildlife Federation (FWF) and partner organizations are working with state and federal departments and private landowners to help fund highway underpasses and safeguard hundreds of thousands of acres of panther habitat. To learn more about the partnership between South Florida’s agricultural community, FWF and other conservation organizations, go to www.floridapantherprotection.com.
NWF is also helping to conserve western lands critical for wildlife such as cougars. To find out more, go to wildlifeacre.nwf.org.
National Wildlife Managing Editor Anne Bolen accompanied Holton and Gus while they were tracking cougars in Grand Canyon National Park.