10/12/2026
Integral Ecology Research Center was recently featured by The Lonely Camp. Read their post to learn more about illicit cannabis' harmful impact on wildlife.
In September 2016, researchers surveying two illegal ma*****na grow complexes in Lassen National Forest found the carcasses of a black bear and a gray fox, with a dead turkey vulture lying right beside the fox. The fox appears to have eaten the poison directly, and the vulture appears to have collapsed after a bite or two of the fox. Flies that landed on the fox’s flesh died within seconds.
Wildlife disease ecologist Mourad Gabriel of the Integral Ecology Research Center watched the flies die while he was taking samples from the carcass. Lab results were still pending when the scene was reported, but his team was reasonably sure the fox was full of poison, and the poison turning up at these grows was often carbofuran.
Carbofuran does not build up slowly through the food chain the way DDT did. It works almost immediately, shutting down the enzymes that let nerves talk to each other until the animal goes into convulsions and stops breathing. Gabriel has said an eighth of a teaspoon would kill a 300-pound black bear.
Because the victim dies so fast, its body becomes the next bait. Biologists call it a circle of death. A scavenger feeds on the carcass and dies, and anything that feeds on the scavenger can die too. Each animal down the line takes in a smaller dose and travels a little farther before it falls, and in one investigation dead animals were found spread across four square miles.
Growers bring the poison into the forest to protect their plants, irrigation lines and camp food. They bait open tuna cans with pesticide, often flavored like meat or peanut butter, and string poisoned hot dogs on fishhooks. Bears photographed walking into contaminated camps were later found dead, and agents have photographed poisoned mountain lions, mule deer and foxes at grow sites.
The chemical has a long record with American wildlife. The EPA once reported that carbofuran was killing one to two million birds a year in the United States, more than any other legal pesticide. It was pulled from the U.S. market in 2009. In February 2016, 13 bald eagles were found dead on a farm on Maryland’s Eastern Shore after eating a raccoon carcass laced with it, and the case was never solved.
California legalized recreational ma*****na in 2016, but in 2024 the state’s own cannabis enforcement chief said the black market is still larger than the legal one, and the forest grows never went away. In July and August 2025, state wildlife officers raided six illegal grows, some of them on national forest land, and seized carbofuran along with methamidophos, another pesticide banned in the United States.
The animals keep finding the sites after the growers leave. Wild animals have chewed through pressurized pesticide sprayers left behind, and pesticides have been found in nearby creeks more than a year after a raid. Researchers have counted nearly 7,000 abandoned grow sites on California’s public lands and know of only 587 that have been even partly cleaned up.
Greta Wengert, co-founder of the Integral Ecology Research Center, calls them “little death bombs, waiting for any wildlife that is going to investigate.”
Image is for illustration purposes only
Sources: bioGraphic (2017) / CBS News (2017, 2025) / Sacramento News & Review (2017) / Audubon Magazine (2020) / The Salt Lake Tribune (2018) / NPR (2024) / CalMatters (2026) / California Department of Fish and Wildlife / Integral Ecology Research Center
