South American bush dogs have recently been seen in the mountains of Costa Rica. Are they expanding their range, or have they been there all along but eluded us?
Stories of animals venturing into and enjoying new places have been one bright spot during the COVID-19 worldwide pandemic of 2020. But even before we had heard of the word coronavirus—a little over a year ago, in May 2019—wildlife ecologists at the University of Massachusetts Amherst who were studying different conservation practices in the forests of Costa Rica reported a startling new discovery caught on a camera trap: documentation of wild bush dogs living farther north and at a higher elevation than previously thought possible. You can view the footage, below.
Natives of South America, bush dogs are small canids that although are widespread throughout their extensive range are very rare in most areas, except in Guyana, Peru and Suriname. They remain mysterious and seldom glimpsed. In fact, when bush dogs were first identified by Danish paleontologist Peter Wilhelm Lund in 1839 from fossils in Brazilian caves, they were thought to be extinct.
Bush dogs baffling ecologists
Due to bush dogs’ elusive natures, most of what is known about them comes from observations of these animals in captivity or from anecdotal sources.
Since 2011, bush dogs have been classified as near threatened by the International Union for Conservation of Nature and Natural Resources (IUCN). Bush dogs are in decline because of an increasing rate of habitat loss and fragmentation—namely, from the conversion of natural areas to urban and agricultural land uses; declines in the bush dog’s prey populations, due to illegal poaching; predation by domestic dogs; and increased exposure to diseases transmitted by such dogs. ©Vassil, Wikimedia Commons
Commonly known as forest dogs, savanna dogs, vinegar dogs, vinegar foxes or water dogs, bush dogs stand no taller than 12 inches at the shoulder and generally weigh about 18 pounds. They’re not closely related to any canines in North America, and scientists cannot quite pin down just who their nearest “cousins” are.
Their size—combined with their long, reddish-tan faces and back fur and slightly elongated muzzles—make them look like miniature bears. But unlike bears, bush dogs have moderately long, five-inch tails. The fur on their legs, tails and underbellies is black, and they have light patches of fur under their throats. Their webbed feet equip them for underwater swimming and wading in wet meadows.
Little is known of bush dogs’ habits. Researchers think that they are diurnal (active during the day, which allows them to avoid jaguar predators) and that they live in social groups of up to 12 animals, with a dominant breeding pair in each pack. While only the alpha female produces offspring in litters averaging four pups, nonbreeding members of the group will guard and care for the young. Males bring food to females in dens, which are often abandoned armadillo burrows or hollow trees.
Most knowledge about bush dogs comes from anecdotal sources or observations of animals in captivity, such as these two playful bush dogs photographed at England’s Chester Zoo. ©Steve Wilson, flickr
Their size and shape make bush dogs uniquely adapted for life on the forest floor. Natural habitats include lowland forests, semideciduous forests, seasonally flooded forests and wet savannas. They’ve never been seen far from water. Unlike many carnivores that have true territories, bush dogs appear to have seminomadic movement patterns. These dogs are extremely vocal communicators and have elaborate systems of contact calls, an adaptation for living in habitats with low visibility.
Formidable hunters, bush dogs work cohesively to capture prey. One member of the pack will drive prey toward the other members. Packs know that prey usually flee into the water for escape, so the other members usually hide in or around the water when hunting. In groups, they hunt agoutis, capybaras, pacas, peccaries, rheas and even tapirs. Solitary hunters sometimes eat ground-nesting birds, lizards, smaller rodents and snakes.
Bush dogs are believed to be able to survive about 10 years in the wild. However, they face several serious threats, including:
1) habitat destruction by human encroachment and loss of intact habitats due to large-scale agriculture, conversion of land to pastures and big plantations of monoculture trees (such as eucalyptus and pine);
Bush dogs are adapted for life on the forest floor and in wet savannas. They are never far from water, such as this river in Costa Rica’s Talamanca Mountains. ©Michel Rathwell, flickr
2) reduction in prey abundance due to illegal poaching and domestic dog predation;
3) pollution of rivers and streams;
4) increased risk of contracting lethal diseases from domestic dogs. Pathogens transmitted by domestic dogs can be potentially devastating, mainly due to bush dogs’ group living; and
5) illegal poaching of bush dogs themselves. Native people, however, do hunt them occasionally for their fur and meat.
According to World Wildlife Fund, capybaras are the largest rodents in the world. Native to South America, these semiaquatic mammals have webbed feet for fast swimming. Capybaras’ ears, eyes and nostrils are on top of their heads, which lets them stay mostly submerged for long periods of time, helping them to avoid their South American bush dog predators.
These considerations are why the International Union for Conservation of Nature (IUCN) ranks bush dogs as near threatened on their Red List.
Bush dogs breaking into new territories
In any circumstances, finding evidence of bush dogs on a trail camera is exciting. But finding them in the Talamanca Mountains—an area well outside the limit of their previously known range—is spectacular news.
In a May 2019 article in the journal Tropical Conservation Science, researchers said the new, repeated sightings of these bush dogs was completely unexpected. While bush dogs have been spotted north of the Panama Canal near the Costa Rica border in the past 10 years, finding them in the northern parts of the rugged mountains was surprising. The doctoral student who discovered the bush dogs was working on comparing land use, management techniques and their effects on species’ presence and abundance, and human attitudes in four different areas in the mountains: an adjacent forest reserve, an indigenous territory, a national park and nearby unprotected areas.
As human settlements encroach farther and farther into Costa Rica’s Talamanca Mountains, bush dogs become more and more threatened by habitat loss and disease.
Because this roadless region is so huge, the scientists are not sure if the dogs are expanding their range, returning to a former range, or if they’ve been there all along but eluded detection. While native people in the area have a name for these dogs and their oral tradition says the dogs have been there in the past, those living there now report that they have never seen one.
Curious about what it would take to collect more sightings of bush dogs in Costa Rica, researchers calculated how many camera-trap hours it might take to have even a fifty-fifty chance of seeing the animals again in an area of roughly 2,000 square miles. It’s estimated that it would require at least 25 camera traps set out for 100 nights, a difficult task in such a remote, mountainous and tropical terrain.
At this point, say the researchers, the Talamanca Mountains look like good bush dog habitat, and the canids seem to be doing well. They state that they hope that their report will spark the imaginations of other wildlife ecologists, park managers and rangers, who might set up their own camera traps in promising areas.
While we’re being bombarded with dire headlines right now, it’s good to remember that the natural world still holds some good news for others of the Earth’s species. ©Erin Smith, flickr
In this time of daily bad-news cycles, it’s good to know that one rare, doglike animal is managing to live and thrive in a wild place we never dreamed it would be able to call home. We greatly need true stories that ignite our imaginations right now, perhaps more than ever before.
Here’s to finding your true places and natural habitats,
Candy
