For over 100 years, humans have hunted top-level predators on British Columbia, Canada’s Gulf Islands. The decline in the numbers of predators led to an explosion in the populations of other species, such as raccoons. Some of the beaches on the Gulf Islands are filled with raccoons that spend much of their time foraging for food. The raccoons eat many of the area’s crabs and fish, which has caused their populations to dwindle.
Ecologists at the University of Victoria may have found a solution to the problem of declining marine populations. They conducted a study and found that the sound of dogs barking could scare away raccoons. The results of the study were published in the journal Nature Communications.
The researchers recorded the sounds of several animals, including dogs and sea lions, and played them from speaker systems on beaches. The raccoons did not react to the sounds of the sea lions and continued eating. They ran away almost immediately when they heard the sound of dogs barking.
The raccoons cut back significantly on their foraging when they believed that they were surrounded by barking dogs. The reduction in their feeding helped to restore a sense of balance to the islands’ ecosystem.
The researchers found that after hearing the sounds of dogs barking, the raccoons spent 66 percent less time eating at the shore. This reduction in eating helped the crab and fish populations rebound. The decline in raccoons’ foraging led to a 61 percent increase in the population of red rock crabs and an 81 percent increase in populations of tidal fish.
One ecologist who participated in the study doubts that this will have a long-term impact on the raccoons’ behavior and the marine population on the Gulf Islands. He believes raccoons will soon overcome their fear of dogs and believes that natural predators such as cougars, bears, and wolves will need to be reintroduced in order to scare raccoons away from the beaches.
