The dictionary of the Royal Spanish Academy defines phobia (from the Greek phobía ‘fear’) as an exaggerated aversion to someone or something. One of the most common is the fear of rats and mice, also known as murophobia. However, many of these rodents, rather than terrifying, can even be friendly, and we hope that they will be even more so for readers after discovering this unusual way they have to cooperate in humanitarian work.
The southern giant pocket rat
To locate ourselves, we will start by talking about our protagonist, the southern giant pocket rat ( Cricetomys ansorgei). This animal measures from 25 to 45 centimeters, although its tail can be 46 centimeters long, and weighs about two kilos. Despite its name, this rodent is only distantly related to what are known as ‘true rats’, located in the Muridae family. Recent molecular studies place giant rats in the family Nesomyidae , part of an ancient radiation of African and Malagasy murids. The name ‘pocket rat’ refers to the large pouches on its cheeks.
These rats are omnivorous and feed on both plants and small animals, especially insects. They are very fond of filling their pockets with nuts and, like many other rodents such as hamsters, rabbits and guinea pigs, these rats are dung and ferment food in their distal intestines , producing soft fecal pellets that contain still semi-digested food that they eat again to complete their assimilation.
Giant rats are capable of reproducing up to ten times a year, with a gestation lasting 27 to 36 days. Each litter is made up of between one and five young that feed on the eight mammary glands that females have.
Giant rats are predominantly nocturnal and are an important food source in many parts of Africa, where their meat is highly prized. In addition, and although it may seem surprising, pocket rats fulfill humanitarian tasks in several countries of the world.
The training of rats
APOPO (acronym for Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling , which in Spanish means “Development of Antipersonnel Mine Removal Products”) is a global non-profit NGO registered in Belgium that uses southern giant pocket rats for the removal of antipersonnel mines. and the detection of human tuberculosis. To do this, they take advantage of the great sense of smell of these animals, which are trained to detect trinitrotoluene (TNT) and the sputum of tuberculosis patients.
APOPO has already supported demining in Angola, Mozambique and Cambodia and it is expected that in the near future it will also be able to work in Zimbabwe and Colombia. In addition, together with more than 140 public clinics, the organization works on the diagnosis of tuberculosis in Tanzania, Mozambique and Ethiopia.
In order to work reliably, rats must be trained for an average of nine months at an estimated cost of 6,000 euros per trained rat. Furthermore, before being ’employed’, these animals must pass an accreditation test. Once outgrown, rats are able to work four to five years before their deserved retirement.
Detection of antipersonnel mines
Rats, being relatively lightweight, can walk through minefields sniffing without the danger of setting off explosives. Once the mines are located, specialized personnel are in charge of removing or detonating them depending on the circumstances.
The advantage of using these rats is that they are much faster in detecting mines than other methods, and the danger of accidental explosions is also eliminated. A rat can search for mines in an area the size of a tennis court in half an hour, while an operator would take around four days to cover the same area.
In addition to improving security, streamlining the process allows affected populations to return to their lands and resume their lives more quickly.
TB screening
As we have already mentioned, these giant rats not only do this important humanitarian work of demining but also help to detect tuberculosis patients.
These incredible rodents are capable of detecting the disease and even find it in samples declared negative by the clinics associated with APOPO, which is responsible for confirming in its laboratory, with tests approved by the World Health Organization, the finding of rats. and to notify clinics of the diagnosis. A rat can examine a hundred samples in less than twenty minutes, a task that would take a technician four days’ work in a clinic.
There is much to do
Despite the work done, there are still sixty countries that suffer from the threat of mines, which constitute a real structural barrier for development and economic growth once armed conflicts end, as thousands of innocent children and adults are injured or killed due to to the mines. Mine detection is a difficult, dangerous, expensive, and time-consuming process.
On the other hand, tuberculosis is the main cause of death from infectious diseases in the world: every year there are ten million new cases and around 1.6 million people die from this disease.
It is clear, then, that there is still a long way to go and that solutions of a very diverse nature are needed, such as the case of these humanitarian rats.
Giant rats’ fine noses may offer other possibilities, and APOPO is working on a project to use them to detect African hardwoods and pangolin scales. Rats could be useful in detecting rhino horn and ivory, as well as drugs and other prohibited substances.
Julio de Castro is a veterinarian and a Doctor in Parasitology. He has worked for FAO for 25 years and now lives in Zimbabwe. Write about your experiences on the Bushsnob blog
