Giant pouched rat

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Giant pouched rat
Cricetomys emini.jpg
Emin's pouched rat (Cricetomys emini)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Nesomyidae
Subfamily: Cricetomyinae
Genus: Cricetomys
Waterhouse, 1840
Species

The giant pouched rats (genus Cricetomys) of sub-Saharan Africa are large muroid rodents.

Contents

Description

Their head and body lengths range from 25–45 cm (10–17.5 in) with scaly tails ranging from 36–46 cm (14–18 in). They weigh between 1.0 and 1.5 kg (2.2 and 3.3 lb).

Taxonomy

Giant pouched rats are only distantly related to the true rats, although until recently they had been placed in the same family, Muridae. [1] Recent molecular studies, however, place them in the family Nesomyidae, part of an ancient radiation of African and Malagasy muroids. The name "pouched rat" refers to their large cheek pouches.

The species are:

ImageCommon nameScientific nameDistribution
Southern giant pouched rat Cricetomys ansorgeiZimbabwe, Kenya, Tanzania, Zambia, and the Democratic Republic of Congo.
Cricetomys emini 2.jpg Emin's pouched rat Cricetomys eminiTropical Africa, Madagascar
CrycetomysGambianus Apsilia 2.jpg Gambian pouched rat Cricetomys gambianusSenegal to Kenya and from Angola to Mozambique
Kivu giant pouched rat Cricetomys kivuensisSouthern Africa

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

A HeroRAT finds a land mine in a training field in Morogoro, Tanzania HeroRAT finds mine.jpg
A HeroRAT finds a land mine in a training field in Morogoro, Tanzania

Detecting explosives and tuberculosis by scent

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 trigger any of the mines including antipersonnel mines. [2] [3] 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 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 400 m2 (480 sq yd) 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. [4]

APOPO is also training the rats to detect tuberculosis by sniffing sputum samples to detect Mycobacterium tuberculosis . The rats can test many more samples than laboratory techniques can—100 in 20 minutes, which would take a lab technician up to four days using conventional microscopy. [5] Furthermore, samples submitted for secondary screening by the rats reassess 52% of initially negative tests are as positive. In some cases TB detected by rats has not been confirmed by clinical tests, but patients later developed TB, suggesting that rats can detect the disease before a clinical test. As of 2024 they were being used to screen for tuberculosis in Tanzania and Ethiopia. [6]

Land mine and tuberculosis sniffing rats are called HeroRATs.

Ben, in the 2003 remake of Willard , was a Gambian pouched rat. [7]

Related Research Articles

<span class="mw-page-title-main">Rat</span> Several genera of rodents

Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus Rattus. Other rat genera include Neotoma, Bandicota and Dipodomys.

<span class="mw-page-title-main">Rhizomyinae</span> Subfamily of rodents

The rodent subfamily Rhizomyinae includes the Asian bamboo rats and certain of the African mole-rats. The subfamily is grouped with the Spalacinae and the Myospalacinae into a family of fossorial muroid rodents basal to the other Muroidea.

<span class="mw-page-title-main">Maned rat</span> Species of rodent

The maned rat or (African) crested rat is a nocturnal, long-haired and bushy-tailed East African rodent that superficially resembles a porcupine. The world's only known poisonous rodent, the maned rat sequesters toxins from plants to fend off predators.

<span class="mw-page-title-main">Muridae</span> Family of rodents

The Muridae, or murids, are either the largest or second-largest family of rodents and of mammals, containing approximately 870 species, including many species of mice, rats, and gerbils found naturally throughout Eurasia, Africa, and Australia.

<span class="mw-page-title-main">Spalacidae</span> Family of rodents

The Spalacidae, or spalacids, are a family of rodents in the large and complex superfamily Muroidea. They are native to eastern Asia, the Horn of Africa, the Middle East, and southeastern Europe. It includes the blind mole-rats, bamboo rats, mole-rats, and zokors. This family represents the oldest split in the muroid superfamily, and comprises animals adapted to a subterranean way of life. These rodents were thought to have evolved adaptations to living underground independently until recent genetic studies demonstrated they form a monophyletic group. Members of the Spalacidae are often placed in the family Muridae along with all other members of the Muroidea.

<span class="mw-page-title-main">Nesomyidae</span> Family of rodents

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, climbing mice, African rock mice, swamp mice, pouched rats, and the white-tailed rat.

<span class="mw-page-title-main">Eumuroida</span> Clade of rodents

The Eumuroida are a clade defined in 2004 by Steppan et al. to describe a group of muroid rodents. The clade is not defined in the standard taxonomic hierarchy, but it is between superfamily and family.

<span class="mw-page-title-main">Pouched rat</span> Subfamily of rodents

Pouched rats are a group of African rodents in the subfamily Cricetomyinae. They are members of the family Nesomyidae, which contains other African muroids such as climbing mice, Malagasy mice, and the white-tailed rat. All nesomyids are in the superfamily Muroidea, a large and complex clade containing 14 of all mammal species. Sometimes the pouched rats are placed in the family Muridae along with all other members of the superfamily Muroidea.

<span class="mw-page-title-main">Nesomyinae</span> Subfamily of rodents

The Malagasy rodents are the sole members of the subfamily Nesomyinae. These animals are the only native rodents of Madagascar, come in many shapes and sizes, and occupy a wide variety of ecological niches. There are nesomyines that resemble gerbils, rats, mice, voles, and even rabbits. There are arboreal, terrestrial, and semi-fossorial varieties.

<span class="mw-page-title-main">Murinae</span> Subfamily of rodents

The Old World rats and mice, part of the subfamily Murinae in the family Muridae, comprise at least 519 species. Members of this subfamily are called murines. In terms of species richness, this subfamily is larger than all mammal families except the Cricetidae and Muridae, and is larger than all mammal orders except the bats and the remainder of the rodents.

<span class="mw-page-title-main">Demining</span> Process of removing land mines

Demining or mine clearance is the process of removing land mines from an area. In military operations, the object is to rapidly clear a path through a minefield, and this is often done with devices such as mine plows and blast waves. By contrast, the goal of humanitarian demining is to remove all of the landmines to a given depth and make the land safe for human use. Specially trained dogs are also used to narrow down the search and verify that an area is cleared. Mechanical devices such as flails and excavators are sometimes used to clear mines.

<span class="mw-page-title-main">Military animal</span> Trained animal used for warfare or other military applications

Military animals are trained animals that are used in warfare and other combat related activities. As working animals, different military animals serve different functions. Horses, elephants, camels, and other animals have been used for both transportation and mounted attack. Pigeons were used for communication and photographic espionage. Many other animals have been reportedly used in various specialized military functions, including rats and pigs. Dogs have long been employed in a wide variety of military purposes, more recently focusing on guarding and bomb detection, and along with dolphins and sea lions are in active use today.

<span class="mw-page-title-main">Working animal</span> Domesticated animals for assisting people

A working animal is an animal, usually domesticated, that is kept by humans and trained to perform tasks instead of being slaughtered to harvest animal products. Some are used for their physical strength or for transportation, while others are service animals trained to execute certain specialized tasks. They may also be used for milking or herding. Some, at the end of their working lives, may also be used for meat or leather.

<span class="mw-page-title-main">Emin's pouched rat</span> Species of rodent

Emin's pouched rat, also known as the African pouched rat, is a large rat of the muroid superfamily. It is related to Cricetomys gambianus, the Gambian pouched rat. Both species belong to Cricetomys, the genus of the giant pouched rats.

<span class="mw-page-title-main">Land mines in Cambodia</span>

Cambodia is a country located in Southeast Asia that has a major problem with land mines, especially in rural areas. This is the legacy of three decades of war which has taken a severe toll on the Cambodians; it has some 40,000 + amputees, which is one of the highest rates in the world. The Cambodian Mine Action Centre (CMAC) estimates that there may be as many as four to six million mines and other pieces of unexploded ordnance in Cambodia. Some estimates, however, run as high as ten million mines.

<span class="mw-page-title-main">Gambian pouched rat</span> Species of rodent

The Gambian pouched rat, also commonly known as the African giant pouched rat, is a species of nocturnal pouched rat of the giant pouched rat genus Cricetomys, in the family Nesomyidae. It is among the largest muroids in the world, growing to about 0.9 m (3 ft) long, including the tail, which makes up half of its total length. It is widespread in sub-Saharan Africa, ranging from Senegal to Kenya and from Angola to Mozambique from sea level to 2,000 m (6,600 ft).

<span class="mw-page-title-main">APOPO</span> NGO that trains landmine- and tuberculosis-sniffing rats

APOPO is a registered Belgian non-governmental organisation and US non-profit which trains southern giant pouched rats and technical survey dogs to detect landmines and tuberculosis. They call their trained animals 'HeroRATs' and 'HeroDOGs'.

<span class="mw-page-title-main">Working rat</span>

A working rat is any rat which is trained for specific tasks as a working animal. In many cases, working rats are domesticated brown rats. However, other species, notably the Gambian pouched rat, have also been trained to assist humans.

<span class="mw-page-title-main">Southern giant pouched rat</span> African species of rodent

The southern giant pouched rat is a species of rodent in the family Nesomyidae. It is distributed in the savannah of East and Southern Africa.

<span class="mw-page-title-main">Magawa</span> Landmine-sniffing Tanzanian pouched rat (2013–2022)

Magawa was an African giant pouched rat that worked as a HeroRAT sniffing out landmines in Cambodia for the non-governmental organization APOPO which trains rats to detect landmines and tuberculosis. Magawa was the most successful landmine-sniffing rat in the organization's history, and received the PDSA Gold Medal in 2020.

References

  1. Mills, Gus & Hes, Lex (1997). The Complete Book of Southern African Mammals. Cape Town: Struik Publishers. ISBN   0947430555.
  2. Wood, Ian (18 December 2007). "Rats being used to sniff out land mines". Telegraph.co.uk. Archived from the original on 26 February 2009.
  3. Giant rats sniff out Mozambique's mines. IOL (29 January 2009)
  4. Weetjens, Bart. How I taught rats to sniff out land mines, TED Talks, Rotterdam, 2010 (accessed 16 September 2011)
  5. "TB Detection". APOPO. 23 August 2024. Retrieved 18 December 2024.
  6. Muiruri, Peter (18 December 2024). "Cheap, smart and efficient: how giant rats are transforming the fight against TB". The Guardian.
  7. "Willard (2013) Trivia". imdb.com. Retrieved 2017-07-14.

Further reading