The Promise of Castor Coexistence

One of the most misguided, counterproductive, and inhumane forms of wildlife management in the United States is the annual mass killing of beavers (Castor canadensis). Each year, tens of thousands of the reclusive animals are trapped, snared, and shot in nearly every corner of the country. Recreational trappers catch beavers for the few dollars their fur and castoreum (a secretion beavers use to mark their territories, and humans use to scent perfume and flavor food) might fetch. The federal government kills them in response to the damage they sometimes cause by felling trees and flooding roads, railroads, and agricultural lands. Most of this killing is cruel, ineffective, ecologically degrading, and unnecessary. That is why AWI is promoting tools that enable us to live with, and benefit from, these remarkable animals.

photo by Chris Moody
photo by Chris Moody

The first problem with killing beavers is that, all too often, the methods used are inhumane. Beavers are frequently strangled in neck snares and crushed in body-gripping (or “Conibear”) traps—large, rectangular devices with metal bars designed to slam shut on an animal’s body, much like a giant mouse trap. Beavers are also ambushed with steel-jaw leghold traps that smash and hold their feet and limbs. Some traps are designed to hold beavers underwater until they drown. Because they are physiologically adapted to holding their breath while they dive for long periods, however, death by drowning is a slow process for beavers. 

Conibears are theoretically designed to kill quickly by slamming spring-loaded bars together on the captured animal’s neck and causing rapid loss of consciousness. However, if a beaver enters the trap at an indirect angle, or a nontarget animal such as an otter, turtle, or heron triggers the trap, it could slam shut on another part of the body, like the abdomen or a limb, causing immense pain and suffering and a prolonged death. Other traps, such as legholds, are designed to restrain the captured animal alive until shot, clubbed, or suffocated by the trapper. Many states, however, allow traps to remain unattended for days at a time. Others have no trap-check requirements at all.

Killing beavers is also ecologically detrimental. Beaver ponds and lodges provide shelter and food for countless species of fish, birds, insects, and mammals, including threatened and endangered wildlife. Beaver ponds produce a wide variety of aquatic insects and lush riparian vegetation, which serve as food and shelter for dozens of species of waterfowl and migratory birds. Trees killed by flooding attract woodpeckers and provide excellent nesting habitat for many types of birds. Salamanders, frogs, newts, and toads use beaver ponds as breeding habitat. Dozens of fish species have been documented in beaver ponds. Moose are attracted to willows that flourish in beaver-created wetlands. 

Beaver-altered landscapes provide additional benefits. Studies indicate that beaver-dammed riparian areas are three times more resistant to fire than surrounding areas and can provide refuges for wildlife during and immediately after wildfires. Beaver ponds help mitigate the negative effects of climate change by lowering overall stream temperature and storing water that can be accessed by animals and vegetation during times of drought. Beaver dams can also improve water quality by reducing sedimentation and removing toxins from the water column. 

Furthermore, killing beavers disrupts families—adult males and females live in monogamous pairs with their offspring. When they are old enough, the young will help their parents repair dams and lodges and may help care for newborns.

Killing beavers not only raises welfare and ecological concerns, it is rarely, if ever, necessary. First, fur trapping today is predominantly a recreation, not a livelihood. In 2015, the Association of Fish and Wildlife Agencies conducted a survey of trappers in all 50 states. One survey question asked how important trapping was as a source of income. In response, only 5 percent of trappers said it was “very important,” 16 percent said it was only “somewhat important,” while 78 percent said it was “not at all important.”

Second, beavers don’t need to be killed to protect property. Trees can be shielded by encircling them with wire mesh fencing or coating their trunks with a mixture of paint and sand that deters beavers from chewing. Roads, crop fields, and other human property can be protected from flooding caused by beaver dams through the use of water flow control devices—systems of pipes and fences that allow a certain amount of water to flow through the dam, thus maintaining the pond at a level acceptable to humans yet still beneficial to beavers and the myriad species that use beaver habitat. 

Critically, flow devices can also prevent beavers from plugging culverts (pipes that funnel water under roads and railroads). Culvert-protective fencing has repeatedly proven effective at preventing beaver-caused blockages. Several studies indicate that heavy-duty wire mesh fencing installed in a rectangular or trapezoidal configuration upstream of the culvert provides a durable solution. This approach is not only dependable but also cost effective. A study conducted in Virginia compared the costs of repairing road damage caused by beavers at 14 sites before and after the use of flow devices. It calculated that the “before” costs of preventive road maintenance, damage repairs, and lethal removal of beavers was more than $300,000 per year. By contrast, it found that the costs of installing flow devices involved a single expense of less than $45,000 and maintenance costs of just $277 per year.

To help promote the use of such ethical, ecologically responsible, and affordable solutions, AWI has long supported the efforts of the Beaver Institute, a Massachusetts-based nonprofit organization that educates the public about how beavers benefit ecosystems, works with landowners and local governments to install flow devices and other preventive measures, and trains wildlife professionals how to properly install and maintain them. AWI is also working to develop a federal program that would provide local governments, agencies, and conservation organizations across the country with resources to implement nonlethal beaver-conflict solutions. In doing so, we are enthusiastic participants in the rapidly expanding community of experts and advocates who recognize the feasibility and promise—for wildlife, humans, and the ecosystems upon which we all rely—of coexisting with Castor.  

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