Gambian Pouched Rats - Exotic Pets and An Invasive Species
Gambian pouched rats are interesting animals. They are sometimes kept as exotic pets and can become very affectionate, although the temperament of individual rats varies. They are also intelligent and playful. In Tanzania they’ve been trained to detect land mines due to their excellent sense of smell and the fact that their bodies are too light to detonate the mines. They've also been trained to detect tuberculosis in human sputum samples.
Gambian pouched rats can grow up to three feet long (including their tail) and can weigh three to four pounds. They are rodents, but they belong to a different family from the common wild and domestic rats. Like hamsters, Gambian pouched rats have pouches in their cheeks to store food. They live in Africa south of the Sahara and are also known as African giant pouched rats.
Unfortunately, a group of animals escaped from a breeder in Florida and colonized an island called Grassy Key, where they’ve become an invasive species. In addition, in 2003 they may have played a role in an outbreak of monkeypox in the United States.
A Young Gambian Pouched Rat
Gambian Pouched Rats in Their Native Habitat
The scientific name of the Gambian pouched rat is Cricetomys gambianus. It's sometimes confused with its relative, Cricetomys emini, which is known as Emin's pouched rat. This species is also kept as an exotic pet. The Emin's pouched rat tends to be smaller and more slender. There are also some coloration differences between the two species.
Strangely, although Gambian pouched rats are common animals and are caught for food by many people, not very much is known about their lives in the wild. The rats may live as solitary animals or in a colony. Research suggests that the males are more likely to be solitary, while the females and babies are more likely to live in a colony.
The animals are found in a variety of habitats that offer some form of shelter, such as areas with trees, rocky outcrops or more open areas that contain burrows dug by other creatures. The burrows often become a network of tunnels once the rats move in. Gambian pouched rats are adaptable animals and migrate to other areas if these are more desirable or if their original habitat is damaged.
The rats are usually nocturnal in the wild and have an omnivorous diet. They eat plants and plant parts, insects, and other small invertebrates. They collect food in their pouches to take back to their burrows and are great hoarders.
Gambian pouched rats are prolific breeders. Females can have their first litter at around five months, and it's reported that in the wild they have from four to nine litters a year! The gestation period is thirty to thirty-two days. The babies are born with their eyes and ears closed and they have no hair. A litter consists of 1 to 6 pups, but generally contains four babies. The animals live for about six to eight years.
A Young Pet Gambian Pouched Rat
Thistle, A Pet Gambian Pouched Rat
An Emin's Pouched Rat Using a Human Toilet
Pouched Rats as Exotic Pets
Gambian pouched rats are bred in captivity. However, they aren't domesticated animals. It takes a long period of selective breeding to fully domesticate a wild animal.
A pouched rat needs to be socialized and trained from a very early age. The animals need lots of exercise as well. Daily handling and attention is very important, even when a pup has come from a careful breeder who is trying to produce good pet animals. Prospective owners need to have time to care for their pouched rats. The animals can't be left in a cage continuously, and when they are let out of their cage they should stay out for a long time. If they aren't petted regularly and played with every day they are likely to quickly lose their friendliness and confidence.
Pouched rats like to run, jump and climb. Their cage needs to be large and have lots of toys arranged at different levels. The rat must be able to move rapidly around the cage, preferably by different routes. The pet will destroy many of the toys, so a replacement supply needs to be available to keep the animal entertained while it's shut in the cage. Of course, all the toys must be safe to chew. The rats have a low body fat content and get cold quickly, so they need to be kept warm.
Pouched rats kept as pets eat a variety of vegetables, fruits, nuts, seeds, grains, meats and egg. The pet's breeder should be consulted about a suitable diet. The rats like to dig into the litter at the bottom of the cage and store food there as well. They usually back into a corner to urinate and defecate. Owners say that pouched rats can be potty trained, using a dish partially filled with water as a toilet, but their litter still needs to be cleaned regularly because it may contain decaying food.
Gambian pouched rats have large and strong teeth. They love to chew and can be very destructive. Although pet rats are often docile, it's important to realize that they could give a painful bite if they wanted to. As with any exotic pet, owning a Gambian pouched rat is a much more demanding job than owning a domesticated animal. The pups are cute, but someone considering buying one needs to do a lot of research about the responsibilities of owning this pet. They also need to think very carefully about the advisability of welcoming a pouched rat into their home.
Training Gambian Pouched Rats - Hero Rats
A Pouched Rat Being Trained to Detect Land Mines
Land Mine Protection and Tuberculosis Detection
APOPO is an organization started by a Belgian man named Bart Weetjens. His goal is to train rats to save human lives by detecting land mines and tuberculosis. The rats are trained with a clicker, just as some pet dogs are trained. The animals hear a click from the clicker and receive a food reward to reinforce their behavior when they perform successfully. Bananas and peanut butter are favorite treats. The animals are known as HeroRATS.
APOPO is based in Tanzania. Both land mines and tuberculosis are big problems in some parts of Africa and in some other countries too. Gambian pouched rats were chosen as helpers because they are trainable, are often friendly and have a great sense of smell. They can detect land mines in both metal and plastic cases. They also live naturally in the area and are long lived, inexpensive to care for and resistant to many local diseases.
When surveying an area for land mines a rat is attached to a harness which is in turn attached to a rope by a leash. The rope is suspended in the air by two human handlers. The rat is trained to scratch the ground when it detects a mine. The area is then marked by the humans and the mine is later removed. According to the APOPO website, two HeroRATS can survey 300 square meters of land in one hour, whereas two manual deminers using metal detectors would take two days.
Animals that are trained to detect tuberculosis enter a cage and sniff a series of holes that have sputum samples underneath. If a rat detects TB it keeps its nose in the hole for at least three seconds and also scratches the hole. APOPO says that the rats can sample 40 sputum samples in seven minutes instead of the full day needed by a lab technician, and in addition the rats detect cases of TB that are missed by humans.
An Emin's Pouched Rat Eating
Gambian Pouched Rats As An Invasive Species
Despite their ability to become delightful pets and their usefulness in helping to save human lives, in Florida feral Gambian pouched rats have become a potential problem.
The situation is thought to have begun when a pet breeder released pouched rats - reportedly six to eight individuals - into the wild on Grassy Key (or when the animals escaped). The rats reproduced rapidly. There were serious concerns that they would damage the habitat, compete with local species and migrate to other environmentally sensitive areas.
Beginning in 2007 poisonous bait was distributed as food. In 2009 the rat population seemed to have disappeared. In 2011, however, new reports of pouched rat sightings appeared, and the reports continued into 2012. A new attack was mounted. Once again it seemed like the battle against the rats was succeeding, but in 2014 it became obvious that the giant rat population hadn't been eliminated.
There are fears that the pouched rats are competing with endangered native wood rats. Officials are very concerned about the rats reaching the mainland and the Everglades. Gambian pouched rats have damaged food crops in Africa and might have a serious effect on agricultural crops on the U.S. mainland. New attempts are being made to remove the animals, which include a trapping program.
Questions and Answers About Monkeypox
In 2003 it was suggested that Gambian pouched rats were implicated in an outbreak of monkeypox in the United States. Monkeypox is a viral disease related to smallpox, although it's generally - but not always - less serious. The virus is often carried inside rodent bodies.
It was discovered that most of the people who became ill with monkeypox had come into contact with infected prairie dogs. It's thought that an animal vendor placed cages containing imported and infected Gambian pouched rats and other infected rodents close to cages containing prairie dogs. This allowed the virus to pass to the prairie dogs. CDC testing showed that one of the pouched rats and several of the other rodents contained the virus in their bodies. Humans may have become infected when they handled the prairie dogs.
Despite the potential problems caused by the rats, I think they are lovely animals. Like any non-native species, though, they are best appreciated in their original environment and habitat where they are endemic.
© 2012 Linda Crampton