Rain drizzles on two beige trailers while eight cats peer silently from within. One black tomcat crawls onto the roof. It crouches tense and afraid, ready to flee at the approach of strangers.
“Holy crud,” says Mary Johnson, an enforcement officer with Missoula Animal Control. “That is a huge cat. Somebody must be feeding it.”
Johnson is visiting one of Missoula’s countless feral cat colonies. In barns and trailer parks and dilapidated buildings across the region, abandoned cats in huge numbers gather for food, shelter and the promise of procreation. In many cases, human caretakers help sustain the colonies with food, water and protection.
The caretaker at this particular colony asked that its location remain a secret.
Nobody knows exactly how many feral cats currently reside in the greater Missoula area, but experts agree there are a lot. Erin Horner, the shelter attendant at Animal Control, estimates that there are probably 100 feral cat colonies in Missoula County alone. “Those range anywhere from 60 or 70 cats in the largest four or five colonies to eight to 10 cats in smaller colonies,” she says.
Despite their abundance, these colonies often go unnoticed.
“Silence is their best defense,” says Karyn Moltzen, a leading cat advocate and founder of the local nonprofit AniMeals. “They are invisible.”
The black tomcat is a perfect example. As Johnson’s truck idles, the animal slinks into the ramshackle trailer. Johnson later learns that the cat is a master at avoiding the traps that animal control officials and shelter staff set out to capture and neuter such creatures. As the dominant feline in a colony of eight, the tomcat has likely produced many kittens over the years.
“Cats can have two or three litters a year and they can start reproducing at five months,” says Mariah Scheskie, the program manager at the Humane Society of Western Montana. “The average litter is four kittens. They are very prolific.” All it takes is two breeding animals and, as Moltzen says, a colony goes “boom!”
Those booming colonies present an increasing challenge to local officials. Despite their ability to survive and reproduce under difficult circumstances, feral cats are not exactly wild animals, and they are certainly not native to western Montana (nor North America, for that matter). They require management and pose serious human health problems, such as rabies and the cat-borne parasitic disease toxoplasmosis, as well as environmental problems, like the devastating predation of birds and small mammals.
The American Humane Association reports that there are as many as 86 million household cats and another 50 million feral cats in the United States today. A 2013 report by scientists at the U.S. Fish and Wildlife Service and the Smithsonian Conservation Biology Institute estimates that free-ranging cats, including ferals, kill between 1.7 and 3.7 billion birds in the continental United States every year. The survey, which was published in the peer-reviewed journal Nature Communications, estimates that cats kill another 6.9 to 20.7 million small mammals in the U.S. annually.
“Our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for U.S. birds and mammals,” write the report’s authors, adding that “unowned cats” cause the majority of these deaths.
Cats are also vectors for diseases that can afflict humans. “For the past 15 years, cats have been the leading domestic animal with rabies. We see up to 300 cases of rabies in cats each year,” says Cathleen Hanlon, rabies team leader at the Centers for Disease Control and Prevention. “… But [toxoplasmosis] is an even more pressing issue than rabies.” Hanlon calls toxoplasmosis “ubiquitous” and “hardy.”
As far as local health officials know, neither disease is a problem in Missoula.
Toxoplasmosis, however, is hard to track. Carried by cats and transmitted through their feces, toxoplasmosis is caused by the parasite Toxoplasma gondii. It can infect humans, travel through their blood stream and lodge in their muscle tissue and brain cells.
“Our most recent survey, a national survey, indicates that about 12 percent of the U.S. population [is infected],” says Jeffrey Jones, a toxoplasmosis expert at the CDC. “…We estimate that about a million people each year are infected, but again most of those people do not become sick.” He says uncooked meat and cat feces are the two major vectors of the illness and that it often presents itself as asymptomatic. In other words, it is a silent disease.
The disease is associated with birth defects and miscarriages in pregnant women, and behavioral changes and neurological disorders like schizophrenia, especially among the immune deficient. Some have called it the “crazy cat lady syndrome.”
These environmental and health concerns have made feral cats in particular, and outdoor cats in general, the object of growing national concern among conservationists, scientists and health officials. And that concern extends far beyond Missoula.