Some scholars are not sure what to believe
In the middle of the 20th century, a group of Soviet scientists set about introducing new species of mammals to the Caucasus. They imported a wide variety of species, from South American chinchillas to Chinese raccoon dogs. However, when they introduced the swamp rat, also known as the coypu or nutria, to Azerbaijan, they couldn't have known they were unleashing a rodent that would become one of the world's greatest pests.
Curious? Check out this gallery to learn more.
Over the centuries, there have been various attempts by humans to introduce, or reintroduce, new or extinct species into different environments.
One of the most well-documented attempts was that of Russian zoologist Nikolai Vereshchagin. His work is still impacting ecosystems today.
He examined cave paintings as he moved through the region, and in 1954 he published a book in which he described the evolution of the Caucasus over the course of 11,000 years.
With his research, Vereshchagin aimed not only to record the ecological history of the region; he also wanted to change it.
One of the main motivations for doing so was to provide more animals that humans could hunt for fur and game. However, there was also a supposed goal of 'enriching' ecosystems.
In an effort to reimagine the landscape, Vereshchagin and his team set about introducing imported animals on a large scale.
In Azerbaijan alone, more than nine species of mammals were introduced. They included short-tailed chinchillas from the Andes and raccoon dogs from China.
Most of the species that Vereshchagin and his team introduced struggled to survive in their new environment. One exception, however, was the giant South American swamp rat.
When Vereshchagin first took the swamp rat, otherwise known as the coypu or nutria, to Azerbaijan, he introduced a modest population of just 213 rodents.
Fast-forward 70 years, and swamp rats can be found in habitats all over the world. What's more, they are recognized as one of the world's 100 most invasive pests.
Swamp rats look a little bit like capybara, social media's most beloved rodent. In general, however, swamp rats have fewer adoring followers.
With orange incisors that never stop growing, and a tail that is around a foot long (or nearly 30 cm), swamp rats have never been much to look at.
They are normally found living in pairs or large colonies, and generally they emerge during the evening to feast on a meal of roots and swamp grasses.
Coypu are able swimmers, thanks to the large, webbed feet on their hind legs. They can also dive for up to five minutes, in order to feed and escape predators.
Swamp rats have various adaptations that have allowed them to thrive in environments all over the world. Indeed, they can now be found on every continent except Antarctica and Oceania.
One important characteristic of the females is that they can give birth to four or five offspring in a single litter.
Couple that with the fact that they can get pregnant again just days later, and you have a species that is able to procreate three or four times a year.
Furthermore, outside of their native South America, coypu have been able to thrive without the threat of their naturally-occurring predators.
That said, there is evidence that they have made their way into local food chains. In Italy, for example, they are hunted by the red fox and the grey wolf.
There are a number of problems associated with swamp rat populations. Firstly, they have a nasty habit of digging burrows in riverbanks, which can destabilize them and cause erosion.
Secondly, they have huge appetites and are known to forage aggressively. According to some accounts, swamp rats eat up to 25% of their body weight, throughout both summer and winter.
In ecosystems all over the world, the appetite of coypu has destroyed farmers' crops and has negatively affected various species of plant, insect, bird, and fish.
Finally, swamp rats have a reputation for carrying diseases that are harmful to humans. One of those diseases is toxoplasmosis.
Toxoplasmosis is an infection that usually has no symptoms; however, it can be dangerous to pregnant women and people with weakened immune systems.
As a result of all this, many countries have been trying for years to eradicate swamp rats. Hardly any have succeeded, however.
One rare exception is the United Kingdom, where, after a coordinated effort of hunting and trapping, the last wild coypu was captured in 1989.
For the rest of the world, full removal is much more challenging, and experts continue to grapple with the harmful effects of artificial introducing a species into a new habitat.
Sources: (BBC)
The Soviet swamp rat experiment
A zoological mission with far-reaching consequences
LIFESTYLE Wildlife
In the middle of the 20th century, a group of Soviet scientists set about introducing new species of mammals to the Caucasus. They imported a wide variety of species, from South American chinchillas to Chinese raccoon dogs. However, when they introduced the swamp rat, also known as the coypu or nutria, to Azerbaijan, they couldn't have known they were unleashing a rodent that would become one of the world's greatest pests.
Curious? Check out this gallery to learn more.