The giant pouched rats of sub-Saharan Africa are large muroid rodents. Their head and body lengths range from with scaly tails ranging from. They weigh between.
Natural history
Giant pouched rats are only distantly related to the true rats, though they were until recently placed in the family Muridae. Recent molecular studies, however, place them in the family Nesomyidae, part of an ancient radiation of African and Malagasymuroids. The name "pouched rat" refers to their large cheek pouches. Females have been said to be capable of producing up to 10 litters yearly. Gestation is 27–36 days. One to five young are born at a time. Females have eight nipples. The animals are nocturnal. They are omnivorous and feed on vegetation and small animals, especially insects. They have a particular taste for palm nuts. Like many related rodents that are hind gut fermenters, they are coprophagous, voiding soft fecal pellets of semidigested food that they eat directly from the anus.
Interaction with humans
In many African countries, giant pouched rats are valued as an important food item. They are easily tamed as pets. However, they were associated with an outbreak of monkeypox in the USA in 2003 and have since been banned from importation to the U.S..
These rats are also becoming useful in some areas for detecting land mines: their acute sense of smell is very effective in detecting explosives such as TNT, and at the same time they are light enough to not detonate any of the mines. The rats are being trained by APOPO, a nonprofit social venture based in Tanzania. The procedure for training rats to detect land mines was conceived of and developed by Belgian Bart Weetjens. Training starts at four weeks of age when the rats are handled to accustom them to humans and exposed to a variety of sights and sounds. They learn to associate a clicker with a food reward of banana or banana-peanut paste. They are then trained to indicate a hole which contains TNT by nosing it for five seconds. Then they learn to find the correct hole in a line of holes. Finally, the rat is trained to wear a harness and practises outdoors on a lead, finding inactive mines under soil. At the end of their training, they are tested: they must find all the mines in an area of that has been seeded with inactivated mines. It is a blind test: their handlers do not know where the mines are. If they succeed, they are certified as bomb-sniffing rats. APOPO is also training the rats to detect tuberculosis by sniffing sputum samples. The rats can test many more samples than can a scientist—hundreds in a day, compared with 30 to 40 by traditional methods. Land mine and tuberculosis sniffing rats are called HeroRats.
