What Wildlife Is Impacted Most By Rat Poison?

August 27, 2021 5 min read

dead rat


People commonly discuss alternatives to poisons when dealing with mouse and rat populations. This stems from secondary poisoning and harming pets and wildlife which weren't the intended target of the rodenticide.  

Because of their toxic nature, these rodent poisons can negatively impact the ecosystem unintentionally. These problems have come to the forefront recently, especially on America's west coast, and have quite literally filled up impressively large books, whether informative or not. Despite this, it is possible to get a good overview of the issue by taking a look at the problem logically.


How the Substances Are Supposed To Work 

It's best to start by looking at how rat poisons are supposed to work. Most rat poisons belong to a group of chemicals known as anticoagulants. This isn't an inherently deadly, or even damaging, classification. In fact, if you've ever known someone with heart problems then you probably know someone who takes an anticoagulant on a regular basis. 

Small amounts of anticoagulants essentially thin out the blood and reduce instances of blood clots. This makes it easier for an impaired heart to pump blood. The main downside for humans is that anticoagulants also increase the time needed for wounds to stop bleeding. This is due to the fact that the same things which cause negative blood clots in our circulatory system are also responsible for the clotting that seals up a bleeding wound. 

In larger doses, an anticoagulant takes that negative side effect to the next level. All living beings will incur small cuts and scrapes as a side effect of normal life. If you look over yourself, you'll probably notice a few tiny scrapes. The same holds true for any living being's organs and circulatory system.

These aren't really an issue because the minuscule wounds typically clot up within seconds. At the most, it might take a few minutes for a tiny scrape to stop bleeding, but high doses of anticoagulants stop wounds from properly clotting up to stop the bleeding. What's more, anticoagulants can actually cause small internal wounds while also keeping them from closing up. 

A high dose of anticoagulants will eventually kill an animal. This typically happens when the animal simply passes away from blood loss. Even a trickle of blood will eventually kill an animal over an extended period of time. What's more, these animals will also suffer from a variety of secondary effects from both blood loss and the poison in their system. These side effects can also cause altered behavior that results in death by accident or predation. This is where the negative effects of rat poisons on animals other than rats and mice starts to become more apparent. 


Springs in the Desert and Food in the Forest Are Always in Demand 

Before we continue, it's important to take a step back and think about how a rat or mouse fits into the larger ecosystem. In nature, almost every living being is continually searching for a meal. If you've spent much time hunting or camping you might have dropped some food on the ground. If you weren't in a hurry to pick it up then you've probably noticed how quickly the life around you takes an interest in your leavings. That's something which happens when you, a large and imposing figure, are near the food. Think about how quickly an easy meal would disappear if you weren't there. Rodenticides fit into this situation in two distinct but dangerous ways.

The first problem is that rat poisons are usually formulated in a way that makes it interesting to rodents, but ultimately, food is food. Even herbivores will often eat meat if they chance on it. And most animals will eat food that's almost, but not quite, suited to their tastes. This includes most rat poisons tailored to attract rodents. 

An animal eating the poison is considered a primary exposure to the substance. You might also be surprised by how deadly rat poisons can be. Prior generations of poison typically took multiple dosing to take effect. Today, the poisons are deployed with fairly massive doses of highly targeted pharmaceutical agents. The end effect is that a dose intended for a tiny mouse can still hurt, or even kill, a much larger animal. And this does happens fairly often. We don't know how common it is for non-rodents to eat rat poisons, but the numbers are thought to be quite high depending on the environment. Again, consider how quickly animals eat food you leave behind in a forest. Animals are always looking for food. 

dad rat

The Walking Wounded 

Now, think back to the previously mentioned side effects of rat poison. Rat poisons can simply kill a rodent, or the substance might cause the animal to become so slow and confused that it's easy pickings for predators. Either method of death will turn the rodent into a meal for other animals. This is where secondary poisoning comes in. This is the most common way for rat poison to hurt other animals. 

A predator will consume a rodent who has, in turn, eaten the rat poisons. The dose of rat poisons is often so high that a predator will get enough of it from prey to suffer ill effects. In fact, a predator will often get enough of the rat poisons from one rodent to kill it as well. The death of the predator may also create less obvious problems. For example, rodent problems can become worse if a predator species that preys on rats is taken out by secondary poisoning. 

We also have the issue of carriers. Anticoagulants typically don't have much, if any, effect on insects. But insects can still carry it in an active state within their bodies. It's easy to imagine a situation where insects have a feast on a stock of rat poisons. Birds then proceed to make a meal out of the insects. The birds eventually eat enough insects with rat poisons in their system to suffer in the same way as if they'd eaten it themselves. 

The secondary transmission of rat poisons also makes it more difficult to get specific data on what species are most impacted by it. When something goes wrong with an area's ecology and food chain, the damage will usually radiate out in an exponential manner. It's like trying to determine where a wave started in the ocean. 

 barn owl

When Predator Becomes Prey 

With all this in mind, it's still possible to speculate on the most common non-rodent to suffer from rat poisons. Obvious examples of animals in danger include mountain lions, bobcats, foxes, and wolves. Secondary or even tertiary poisoning is a big problem for many different species, but birds of prey, also known as raptors, are the most at risk.

The main problem for raptors comes from both specialization and appetite. Birds of prey are especially fond of rodent-based meals. Animals like owls can even swallow an entire mouse whole. This appetite is fairly widespread among raptors. It's also quite common for a bird to essentially eat an entire rodent. And when birds eat that rodent whole they're also getting a lot of the rat poisons into their system. Plus, there's also a wide variety of raptors which fit different ecological niches. For example, owls eat rodents at night. Meanwhile, falcons and hawks eat rodents by day. 

A24 Automatic Rat Trap

Handling a Rodent Problem 

As you can see, there's inherent problems with most rat poisons. Even in your own home there's potential dangers for accidental ingestion from pets or even children, and we've only touched on how much damage rat poisons can do to the environment. All of these reasons and more are why it's better to use an environmentally safe, toxin-free, trap. These items are specially designed to take care of rodent problems without becoming an issue unto themselves. Though as with most rodent control options, the sooner you deploy it the more effective it'll be, so make sure that you decide on an environmentally-friendly method of rodent control as quickly as possible.

The Homeowners Guide To Catching Rats & Mice

Every year, rats and mice enter 20 million U.S. homes uninvited. They reproduce rapidly, and can cost thousands of dollars in damages and extermination costs. They can ruin equipment, spoil food and start fires by chewing on wires.

We’ve trapped millions (seriously, millions) of rats and mice and the knowledge of what it takes to achieve success is highlighted in this guide.

Homehowners Guide to Catching Rats


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