One of the more invasive species, nutria rats are large rodents that can weigh up to 20 pounds and live near wetlands. If you have a garden or farm, you may know all too well that nutria rats love to eat crops such as corn, alfalfa, wheat, or sugarcane.
There are a couple of ways you can get rid of nutrias if you find one in your garden or crops, including shooting it with a gun or bow and arrow. You can also set a trap for it and humanely dispose of it after it is in the trap.
Nutria rats are not a native species to countries such as the United States and European countries, and you might be wondering what they’re even doing here in the first place. Read on to learn more about these rodents of unusual size.
Techniques for Getting Rid of Nutria Rats
When you know you have nutria rats in the area, you can place baited poison around for the nutria to find and eat. But what do you do if you just come across a nutria rat? There are a couple things you can do to take care of the problem right away, including shooting it and setting a trap.
If you see a nutria in your garden or yard, the fastest way to get rid of it is by shooting it. This is a quick and easy solution if you have enough space to make firing a gun safe and if your county allows you to discharge a gun. A bow and arrow are another option for safely shooting a nutria rat.
While some states, such as Oregon, allow you to shoot nutria on your own property at any time, other states may require you to get a permit before shooting.
This is one of the best ways to eradicate nutria rats, especially if you can’t shoot them in your area. You will need either a leg hold trap or a live double door trap. Move carefully so you do not frighten the nutria away and place the trap nearby with a carrot or other vegetable as bait. Once you have trapped the nutria, you should humanely dispose of it so it will not come back.
If you want to sell the pelt of the nutria rat you killed, you will most likely need a special permit to do this. Laws vary depending on what state and city you live in, so you should always check those laws before taking action.
Are Nutria Rats Dangerous?
Nutria can be up to 1.7 feet long and weigh up to 14 pounds. Because they can get so big, you definitely want to be careful around them!
Danger to Humans
While nutria rats sometimes run away if they feel threatened, they can also become aggressive if they feel threatened. They are also scared of humans, and if they feel trapped, they can show aggressive behaviors. You and your pets should be careful if you come across nutria rats.
Danger to Animals
It is common for nutria rats and small pets to fight, especially during the summer when they are most active. Because nutrias are very territorial, they may fight with domestic dogs sometimes. Because of their size and the fact that they fight by scratching and biting, domestic dogs can sometimes be injured after a run in with a nutria rat. They may even need stitches after the fight. If you know you have nutria rats in your area, you should keep your dog on a leash.
Do Nutria Rats Hibernate?
Nutria rats do not hibernate in the winter, so you might see them all year round! In fact, a nutria rat’s peak reproductive season begins in the late winter, as well as in the early summer and middle of autumn.
Generally, nutria rats are even more destructive in the winter because food is scarce, and they have to try harder to find food. Usually, they will eat roots and shoots of young marsh plants, eating about 25 percent of their body weight every day. But in the winter time, these plants die off when the weather turns cold.
While nutria rats do not hibernate in the winter, they do try to stay warm. During cold parts of the year, they have been observed piling up to stay warm.
Research in recent years has shown that as winters become milder, nutria rats have been moving northward in the United States. They may be expanding their range to include places such as the Atlantic, the Pacific Northwest, and the Mississippi Valley. The study showed that by the year 2050, nearly all of the states in the U.S. will be hospitable for nutria rats, even in the coldest parts of winter.
In the past, nutria rats have migrated north or south, depending on the severity of the winters. But since winters are getting warmer, they are migrating more north than south.
On the other hand, years with colder winters can help control the nutria rat population. Since they do not hibernate, winters are often hard for them. Finding food is difficult, and they often get frostbite on their tails. This frostbite can lead to them dying, and during the coldest winters, they can go extinct in local regions. For example, during the 1980s, nutria rats went extinct in Scandinavian countries after a few hard winters.
Are Nutria Rats Endangered?
Nutria rats are far from endangered. In fact, they are so prolific that they are considered an invasive species. They are a danger to swampy areas, and they put endangered animals in these wetlands at risk.
However, when fur pelts were in demand, the nutria rat was locally extinct in its native region. Keeping nutria rats on fur farms solved this problem.
How is the Nutria Rat an Invasive Species?
An invasive species is defined as one that is not native to the ecosystem and that causes significant harm to either the local ecosystem or to human health. Nutria rats fit both of these definitions – they are not native, and they damage the local environment.
Nutria rats are also an invasive species because they multiply very quickly. They will have two to three litters a year, and each litter will have four to five babies in it. But some litters can have up to 13 babies! While nutria rat reproduction is at its peak in the middle of the autumn, at the end of winter, and the beginning of summer, nutria rats can reproduce at any time of the year.
Nutria rats are ready to breed by the time they are four to seven months of age. The female nutrias are pregnant for about four months, and they can breed again within only two days of giving birth!
The nutria rat is such an invasive species because their number can increase astronomically. For example, in 1938, 20 nutria rats were introduced in Louisiana. Within 20 years of this, the number of nutria rats had soared to over 20 million.
Why is the Nutria a Problem?
Nutria rats eat marsh plants such as salt meadow cordgrass, cattails, and Olney three square. The nutria rat uses its large front feet and claws to dig up these marsh plants. This damages the local ecosystem because all the digging causes erosion. Since each nutria rat consumes about a quarter of its body weight every day, and they weigh up to 14 pounds, each nutria rat is eating about three and a half pounds of these marsh plants every day!
Because nutria rats only eat the roots and stems of marsh plants, they can destroy up to 10 times more plants than they actually eat. When they eat the roots, the plant will not grow back. Marshes provide protection from flooding as well as a home for other wildlife such as birds and fish. But when the population of nutria rats has been particularly high, they have been known to destroy entire marshes.
Nutria rats also use the vegetation in the marsh for giving birth, grooming, and resting. They mat the vegetation down in a circular motion. This often kills the plants. When too many plants in a marsh die, the marsh itself often dies as well.
For example, in the Blackwater National Wildlife Refuge, over 5,000 acres of marshland have turned back into open waterways. This has resulted in increased flooding, ditches and streams filling with too much water, and even timber dying off as the saltwater comes further inland.
Since nutria rats also like to dig, they sometimes create burrows and dens in embankments and dikes. This leads to erosion, and sometimes the entire embankment will collapse. In the Chesapeake Bay, for example, tens of thousands of acres of marshland have been lost due to the erosion caused by nutria rats.
Finally, nutria rats have harmed the agricultural industry because of their love of digging. These animals like digging in steams and drainage ditches, and this harms the farmers’ corn and soybean crops.
Efforts to Control Nutria Rat Populations
Because the nutria rat is such an invasive species and causes so many problems, many areas have made efforts to control it. For example, in Louisiana, the Coastwide Nutria Control Program encourages people to trap the nutria for its fur. In the first year of the program alone, 308,160 nutria rats were harvested, and the program paid out $1,232,640 to people who had participated in it.
Program participants trap as many nutria rats as they can and cut off the tail of each nutria rat. The program pays out $5 for each nutria rat tail. The participants let an official in the program know when and where they trapped each nutria, and this information goes into a database.
The database helps the program keep track of where nutria populations are the biggest. They also use aerial photographs to determine how much damage these populations have done to local marshes and ecosystems.
One other potential nutria rat control measure that has been considered is not effective. This is using a rodenticide, but zinc phosphide is the only one that will kill nutria rats. The problem with this option is that zinc phosphide is very expensive, and it is toxic. Its toxicity stays in the area for a long time, and it is unknown what type of effect it would have on other animal and plant life. While it remains toxic for a long time, it also becomes less effective for nutria rats when it rains, or the humidity is very high.
In Europe, nutria rats are considered one of the most invasive species in the continent. Great Britain had a nutria rat problem that started in the 1930s when some of these rodents escaped from fur farms. By the 1950s, they had spread so much that they were damaging the local agriculture.
The government had a campaign from 1962 to 1965 so trappers could catch and kill nutria rats. This reduced the nutria rat population significantly, but by the early 1980s, the population was on the rise again. This time, the eradication campaign was successful and completely wiped out the nutria rat population in Great Britain.
Other countries do not even want to allow nutria rats in the first place. For example, the Hazardous Substances and New Organisms Act 1996 in New Zealand prohibits anyone from bringing in nutria rats.
Do Nutria Rats Carry Diseases?
Nutria rats carry many diseases, including salmonellosis, rabies, toxoplasmosis, and equine encephalomyelitis. They also carry parasites including ticks, fleas, and louse. Nutria rats can give these diseases to humans, pets, and livestock animals. While they can spread these diseases to humans and animals, it is not well known how the nutria rat transfers these diseases.
But one thing we do know is that handling nutria without gloves can lead to a problem called “nutria rash.” This is caused by a tiny roundworm called a strongyloides myopotami. The roundworm lives in the nutria and can burrow into your skin, leaving red trails and causing severe itching and inflammation. The good news is it is treatable through topical medications or steroids, depending on how severe the case is.
In agricultural areas where nutria rats live, it is important to keep an eye on water supplies for animals and regularly provide fresh water. Nutria rats may pass on diseases to livestock if their feces and urine has contaminated the livestock’s water.
Are There Nutria Rats in Florida?
Nutria rats live in Florida, and in fact, they have become an invasive species there. The Everglades and other swampy areas of Central Florida provide a perfect home for these water-loving rodents. As in other parts of the United States, nutria rats first arrived in Florida because of the fur trade. A few nutria rats were also released because they were thought to control undesirable aquatic plants.
In Florida, nutria rats are a problem because they can destroy canals. Because Florida is so flat, canals in residential parts of the state manage water and prevent flooding when it rains. But nutria rats can burrow into the canals, destroying them. The good news is Florida alligators will prey on nutria rats.
What Animal Eats Nutria Rats?
Nutria rats’ main predators were humans who trapped them for their fur. But animals such as alligators, cottonmouth snakes, and even turtles will prey on them. Birds of prey such as owls, hawks, and bald eagles will also target nutria rats.
Unfortunately, nutria rats are nocturnal, and besides owls, most of their predators are more active during the day. This means these predators are not effective at controlling the nutria population. Nutria rats also hide in their burrows when they can, which makes it harder for most predators to get them.
How Did Nutria Rats Get to the U.S.?
Nutria rats originally came to the U.S. because of the fur industry. Louisiana once led the United States in producing muskrat and mink fur pelts. Because fur prices were so high, trappers in the state could make a lot of money selling the fur.
Louisiana started trading furs in the 1700s because New Orleans was on the Mississippi River and could easily trade their furs. By the early 1900s, so many people were trapping animals that the government required trappers to get licenses. Bringing the nutria rat to Louisiana for its fur was a natural step for people who sold fur.
In the 1930s, some Louisiana nutria rats were released, either accidentally or on purpose, into the marshes in Louisiana. The nutria quickly established themselves near the Gulf Coast. As people trapped these wild nutria rats, they further spread them into other marshes. At first, the government promoted the nutria rats as helping to control aquatic weeds such as water hyacinth, and they moved the nutria rats around the southwestern part of Louisiana. But a decade later, they began to realize just how much damage the nutria rat does to marshes.
By the 1950s, nutria rat fur pelts were in the highest demand in Europe, and prices for the nutria rat’s fur were at their peak. But in 1955, so many people were producing nutria rat pelts that the prices dropped drastically. Producers needed to find a new market, and eventually Germany began importing furs.
The nutria rat furs were at their peak in 1976 at $15.7 million. But after this, the demand for furs in general began to decline, this time for good. This was partly because too many nutria rats fur pelts were being produced, but also because they were going out of fashion. The animal rights movement contributed to this as well as an economic downturn.
This meant that nutria rats that were being bred for their fur had nowhere to go but out in the marshes. These nutria rats spread quickly.
How Does the Nutria Spread?
Nutria rats reproduce prolifically because they can have so many young each year. This is a problem because they are not a native species, and so they have very few natural predators to help control their population.
In Blackwater National Wildlife Refuge in Maryland, it was estimated there were about 250 nutria rats in 1968. But by the late 1990s, it was estimated that that number may have been as many as 50,000!
Nutria rats like wet areas because of the vegetation that grows in those areas, so when they spread, they look for similar areas. One study on nutria rats in South Korea has shown that when the population of nutria rats gets too big in an area, the extra nutria move further up or down the river to find new suitable areas to live in.
The nutria rats will continue moving along the river until they come to an area suitable for starting a new population. The study showed that factors such as the availability of food, slow moving water, and levees where they could burrow all went into determining what location they would choose to settle down in. They were also more likely to choose a location where the winters were not too cold.
Is It Legal to Kill Nutria Rats in Oregon?
In Oregon, you can kill nutria because they are not considered to be protected wildlife. This means you can trap them and kill them, and you do not need a permit to do this. However, nutria rats are also not considered game, which means you can’t relocate them. Of course, we have already seen the problems that come with relocating nutria rats, so it is best to trap or kill them anyway.
Mike Zhang. Founder of FamilyLifeShare