Raccoons are creating a menace offshore British Columbia in Canada due to the elimination of carnivorous predators like local bears, wolves and cougars, which were killed by humans. These predators actually kept a check over the island raccoons, which are capable of causing extreme damages. Domestic dogs are the only natural predators existing on the majority of the islands.

Island raccoons started coming out in broad daylight for strolling and hunting. The population of coastal animals like crabs, worms and fish is decreasing at a shocking rate. Raccoons partially eat crabs and leave the remaining parts. Ecosystem of the island is facing disturbance due to missing large carnivorous predators.

A hypothesis on the role played by the predators in an ecosystem was tested by the researchers. Though smaller predators are kept under control by large predators, however, environmental scientists think that ‘ecology of fear’ is developed by predators thereby restraining smaller predators, like island raccoons, from wandering around.

Testing the hypothesis involved installing speakers along two parts of the coastline, with speakers relaying dog barking sounds. Cameras were installed to capture the behavior of raccoons. Samples of crabs and other animals eaten by raccoons were also collected to study the impact of testing on their population.

It was found that the hunting of raccoons reduced by 66% and several of them stopped coming out on the coastline. Raccoons have become more alert and they come out only when they need food. Revealing the impact of the test on the population of raccoon’s food items, the researchers said, “There were 97% more intertidal crabs, 81% more intertidal fish, 59% more polychaete worms and 61% more subtidal red rock crabs.”

Scarecrow’s sonic equivalent was created by the researchers for testing and this proved successful as the dog barking resulted in strong shift in the behavior of raccoons just with the sense of fear.