Anticoagulant rodenticide poison (rat poison) has long been the go to deterrent for nuisance rodents but it’s important to know that these deadly chemicals can work their way up the food chain and get more lethal as they accumulate in larger animals like mountain lions.
Hidden in plain sight from Los Angeles, the Santa Monica Mountains National Recreational Area is a surprisingly wild place, with over 500 miles of trails and stable population of mountain lions. Major causes of death among the resident mountain lions include vehicle collisions, intraspecific strife (mountain lions killing other mountain lions) and rodenticide poisoning. As of December, 2022, 39 out of 40 local mountain lions have tested positive for exposure to one or more rat poisons and seven have died directly of poisoning:
“Anti-coagulant rodenticides are designed to kill rodents by thinning the blood and preventing clotting. When people put these bait traps outside their homes or businesses, they may not realize that the poison works its way up the food chain, becoming more lethal as the dose accumulates in larger animals.” –Dr. Seth Riley, Urban Wildlife Expert @ Santa Monica Mountains National Recreation Area
There are many ways to control rodent infestations without anticoagulants, including removing food resources and hiding places, using snap and/or electric traps, and contacting a pest-exclusion company that uses sustainable practices known as Integrated Pest Management (IPM). IPM is an environmentally sensitive approach to pest management that relies on a combination of common-sense practices.
Remember folks, rat poison can have fatal effects on non-target wildlife and contamination can stretch to food webs far beyond your backyard.
The use of anticoagulant rodenticide poison to control rodents in your yard, neighborhood and community can result in exposing your pets and local wildlife to this deadly poison. Regardless of who distributes the poison — homeowners, professionals, or your HOA — your pets and local wildlife are at risk of exposure.
Death from anticoagulant rodenticide poisoning takes longer than you might think. Rodents that consume anticoagulant poisons do not die immediately. The poison is designed to block the vitamin K cycle which is important in clotting the body’s blood, often resulting in a slow death.
It can take up to 10 days for the rodent to die by internal bleeding, if it is not eaten by another animal first. Rodents filled with toxic anticoagulant rodenticide poisons continue to move around in the environment and as they start to feel the effects of the poison they begin to move slower and become easy targets for your cat, dog and our native predators such as bobcats, hawks, owls, coyotes etc. Research has shown that anticoagulant poison moves up the food chain and eating a poisoned animal can lead to secondary poisoning of dogs, cats and many wild animals.
How are pets and wildlife getting poisoned?
Unintentional Poisoning
Non-target species are poisoned through primary, secondary and tertiary poisoning.
Primary Poisoning of non-target animals may occur when a bird eats the pellets broadcasted on the landscape or pellets that fall out of the bait box. Domestic dogs have been poisoned when they eat bait from boxes or get into unsecured packaging in their homes.
Secondary Poisoning of non-target species occurs when predatory animals eat poisoned animals, therefore ingesting the poisons secondarily. For example, a bobcat eats a poisoned gopher, exposing the bobcat to the poison, creating a secondary exposure to the poison. Your cat could be at risk too. If your cat ventures outside it will likely catch or try to catch a small mammal, if that mouse, rat, squirrel or rabbit has eating poison your cat is at risk of secondary poisoning.
Tertiary Poisoning of non-target species occurs when a predatory animal eats another predatory animal that has been secondarily poisoned. For example, a mountain lion eats a coyote with secondary poisoning that ate a poisoned squirrel.
Anticoagulants move through the food chain.
Research discovers rodent poisons move up the food chain.
Wildlife affected in our local Southern California neighborhoods:
Scientific research on local wildlife in the Santa Monica Mountains National Recreational Area and surrounding fragmented habitats has detected startling evidence on how many of our native carnivores are exposed to anticoagulant rodenticide poisons. This research has shown that secondary poisoning from anticoagulant rodenticides is a wide spread problem throughout our local landscape. Testing results from the 3 carnivore species (bobcats, coyotes and mountain lions) monitored in this study found that most of the animals in the study were exposed to anticoagulant rodenticides.
Results from tested bobcats, coyotes and mountain lions, and exposure to anticoagulant rodenticides during NPS study:
Bobcats – 92% of bobcats exposed to anticoagulant poisons.
Coyotes – 83% of coyotes were exposed to anticoagulants and it was the 2nd leading cause of death during study.
Mountain Lions – 94% of mountain lions were exposed to anticoagulant poisons, including a 3 month old kitten.
How you can help?
Take Action Against Anticoagulant Rodenticides
How can I control rodents without anticoagulants?
Alternatives to Anticoagulant Rodenticide Poisons
- Before you have a rodent problem: Remove food resources and hiding places.
- If you have rodents: Use snap and/or electric traps to remove rodents. Remember also that you need to remove food resources and hiding places to prevent rodents from returning.
Reduce food sources for rodents
- Remove or prevent rodent access to fruit and nut trees – trim trees away from fences, roofs, and telephone lines; attach tree guards on tree trunks
- Prevent access to vegetable gardens – cover or enclose with net or wire
- Clean up and seal up domestic animal food, dog, chicken, horse etc.
- Remove bird feeders
- Clean up and seal up trash
- Seal up compost piles
- Clean BBQ after using
Reduce hiding places and shelter for rodents
- Seal up holes and cracks into house, attic, crawl space, garage, sheds, etc.
- Clean up wood/brush/junk piles that provide shelter to rodents
- Remove thick vegetation, specifically ivy, where rats can nest
- Remove tree limbs within three feet from roof
If your rodent problem is too big for you to control, contact a pest-exclusion company that uses sustainable practices. Pest control companies that practice Integrated Pest Management should be able to help you get to the root of the problem; seal up holes and trap rodents without the use of poisons.
Controlling rodents without anticoagulant rodenticide poisons may not always be easy but it will help benefit the health of our native wildlife.
