The giant pouched rats (genus ''Cricetomys'') of sub-Saharan

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

are large

muroid The Muroidea are a large superfamily of rodents, including mice, rats, voles, hamsters, lemmings, gerbils, and many other relatives. Although the Muroidea originated in Eurasia, they occupy a vast variety of habitats on every continent excep ...

rodents Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are nat ...

. Their head and body lengths range from with scaly tails ranging from . They weigh between .

Taxonomy

Giant pouched rats are only distantly related to the true rats, although until recently they had been placed in the same family,

Muridae The Muridae, or murids, are the largest family of rodents and of mammals, containing approximately 1,383 species, including many species of mice, rats, and gerbils found naturally throughout Eurasia, Africa, and Australia. The name Muridae come ...

. Recent molecular studies, however, place them in the family

Nesomyidae The Nesomyidae are a family of African rodents in the large and complex superfamily Muroidea. It includes several subfamilies, all of which are native to either continental Africa or to Madagascar. Included in this family are Malagasy rodents, ...

, part of an ancient radiation of African and Malagasy muroids. The name "pouched rat" refers to their large cheek pouches. The species are:

Behaviour

Females have been said to be capable of producing up to 10 litters yearly. Gestation is 27–36 days. The animals generally have between six and eight nipples. One to five young are born at a time. The animals are

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...

s, and feed on vegetation and small animals, especially insects. They have a particular taste for palm nuts.

Interaction with humans

In many African countries, giant pouched rats are valued as an important food item. They are easily tamed as

pet A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory animal. Popular pets are often considered to have attractive appearances, intelligence, ...

s, but were associated with an outbreak of monkeypox in the USA in 2003, and have since been banned from importation to the U.S.

Detecting explosives and tuberculosis by scent

These rats are also becoming useful in some areas for detecting

land mine A land mine is an explosive device concealed under or on the ground and designed to destroy or disable enemy targets, ranging from combatants to vehicles and tanks, as they pass over or near it. Such a device is typically detonated automati ...

s; their acute sense of smell is very effective in detecting explosives such as

TNT Trinitrotoluene (), more commonly known as TNT, more specifically 2,4,6-trinitrotoluene, and by its preferred IUPAC name 2-methyl-1,3,5-trinitrobenzene, is a chemical compound with the formula C6H2(NO2)3CH3. TNT is occasionally used as a reagen ...

, and at the same time they are light enough to not detonate any of the mines.Giant rats sniff out Mozambique's mines
''IOL'' (29 January 2009) The rats are being trained by

APOPO APOPO (an acronym for Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling: "Anti-Personnel Landmines Detection Product Development" in English) is a registered Belgian non-governmental organisation and US non-profit which trains southern giant ...

, a nonprofit social venture based in Tanzania. The procedure for training rats to detect land mines was conceived of and developed by

Belgian Belgian may refer to: * Something of, or related to, Belgium * Belgians, people from Belgium or of Belgian descent * Languages of Belgium, languages spoken in Belgium, such as Dutch, French, and German *Ancient Belgian language, an extinct languag ...

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 A clicker, sometimes called a cricket, is any device that makes a clicking sound, usually when deliberately activated by its user. They usually consist of a piece of thin metal or plastic held in a casing so that the metal is slightly torqued; ...

with a food reward of banana or banana-peanut paste. They are then trained to indicate a hole that 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.Weetjens, Bart
How I taught rats to sniff out land mines
TED Talks, Rotterdam, 2010 (accessed 16 September 2011) APOPO is also training the rats to detect

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...

by sniffing sputum samples. The rats can test many more samples than a scientist can—hundreds in a day, compared with 30 to 40 by traditional methods. Land mine and tuberculosis sniffing rats are called HeroRATs.

In popular culture

Ben, in the 2003 remake of '' Willard'', was a Gambian pouched rat.

References

External links

APOPO's HeroRATsUKpouchies, free information siteNational Pouched Rat Society, NPRS Pouched Rat Society
{{DEFAULTSORT:Giant pouched rat Rodents of Africa Cricetomys Taxa named by George Robert Waterhouse