The African Giant Pouched Rat; An Animal Conditioned To Save Lives

Cover Photo Credit: Aaron Gekoski

My passion for training animals for conservation purposes is starting to grow. In the Zoo I work at, I get to do a lot more research training and become more skillful in conditioning animals to be ready for research projects. This gives me a whole different view on what works and how we should train the animals differently.

Recently I came across an organisation that conditions rats to find landmines called Apopo. Apopo was founded in the 90s with its main goal to save lives. They picked rats to help them reach this goal for a pretty good reason. A rat can cover up to 400m2 in 45 minutes, while a person with a metal detector would take around 4 days. 

Apopo’s mission is to develop detection rats to provide solutions for global problems and inspire positive social change. 

Civil unrest and war have lead there to be many land mines left in Africa, Thailand, Cambodia, Laos and Vietnam. As we know landmines are explosive devices that are designed to blow when triggered by pressure or a tripwire. These devices are typically found on or just below the surface of the ground. In these countries it means that at any moment there is a chance that someone could step on a potentially fatal weapon. Apopo works closely with these countries to help implement their successful project with their rats. They have saved many lives by conditioning their rats to find the bombs.

The rats that are used in this training are African Giant Pouched Rats. Their behavioural characteristics make them perfect for the job. They have:

    •    Highly developed sense of smell.
    •    Intelligent and easy to train.
    •    Too light to set off the landmines.
    •    Locally sourced and widely available.
    •    Easily transferable between trainers.
    •    Cheap to feed, breed and maintain.
    •    Live 6-8 years.
    •    Indigenous to Sub-Saharan Africa they are resistant to most tropical diseases.

Training the Rats

“After passing the socialisation tests the baby rats move on to basic training around 5-6 weeks. Here the young rats first hear clickers and receive rewards in order for them to associate the sound with food, and be later motivated to carry out trained actions such as searching out the target scent.” Source; Apopo.org

Apopo uses operant conditioning with their rats to find landmines, tuberculosis and pangolin scales. As you can imagine there is a lot of sense work involved in training these rats, something I have limited experience with; so we decided on a Skype interview with Apopo to discover what their techniques are in different situations.

Zoospensefull: It is very interesting to see how successful this scent work is with these rats. Is it always this successful or is this also based on the individual rats and what do you look at characteristically?

Apopo: The rats aren’t necessarily selected, one will go faster through the training program as others. If some rats have some problems in the fields they will get them to retirement a lot earlier. The training program with the rats is highly successful, in fact, all the rats make it to become landmine detectors or TB rats. Sometimes we let them choose.

A PHD student from Antwerp did his thesis at Apopo and discovered that some rats will have a preference to different projects. They can now ask the rat whether it wants to work on the landmine project or a tuberculosis project.

Reinforcement Choice

Reinforcement is always an important part in training to think about. When I’m going to different zoos and hear about their challenges one of my first questions is what reinforcement do you use and is this really reinforcing for the animals. Discovering what reinforces the animal in particular situations will help you training your animal and sometimes the reinforcer is completely different as what you thought off at first. Planning your reinforcement helps the growth of your training program.

Zoospensefull: What is used as reinforcement and do you also use other reinforcers than food to motivate the animals to participate? 

Apopo: When the animals are very young they use a mixture of bananas, avocados and crushed rodent pellets all mixed up and added in a syringe. When the rats are adults bananas and peanuts are used to reinforce the them. 

The trainers make sure to only use food. The reason they don’t focus on tactile or relationship building is because when the rats have to go to a project, the trainers will not follow. This means that anybody should be able to be train the rats and using only food will help this process.

The goal is to have the rats understand that the smell of TNT is needed to receive a click and a reward. In the early stages of the rats life these items are connected to each other. When they have had X amount of correct responses, then the animals will be taken to the next stage of training to eventually be ready to find landmines.

Communication

Animal training is all about communication. As trainers we have to tell the animal what we would like them to do and we can motivate the right choice by adding reinforcement at the right moments. In projects, such as finding landmines, there is communication coming back from the animal as well. This way the trainer knows when the rat has found something.

Zoospensefull: How does the animal tell you they found something? 

Apopo:The rats are trained in different stages, when they understand what the clicker means they add a tea steeper with TNT in them. Whenever the rat puts his paws on there the click comes and reinforcement. To make sure the rat goes for the TNT and not the metal steeper, various items with other smells are introduced. When the rat is successful in locating the TNT, they will hide it under the soil and when the rat starts digging for the item the animal will get reinforced. 

African pouched rats are nocturnal and their sight is not their strongest sense. They rely on their hearing and sense of smell as their primary senses. They are foragers and take all they find back to their nests. 

This foraging behaviour is used and reinforced to give the trainers a sign that the animal found something.  

When errors occur

Within training sessions it can happen that the animal does not understand what you meant or the animal lost part of the behaviour. We can’t ask the animal what happened but through observation and pro-active planning we can keep the animal on high rates of success.

Zoospensefull: If a rat is not able to find a landmine, do you still reinforce the animal for trying?

Apopo: The rat will not get any reinforcement when it doesn’t find anything. However, one day a week the rats will be taken to a training camp where their confidence with finding landmines will be reinforced. This is where they retrain the rats to find landmines. 

Zoospensefull: What is the length of one session before the reinforcement happens? 

Apopo: Every morning the rats will do their search session which can take up to 45 minutes. In this time frame they will cover up to 400m2.

Zoospensefull: When do you decide that a rat is ready for the real thing? 

Apopo: The rats need to be 100% successful to go to the next stage of the project. 

Conservation Work

Apopo.org is doing some wonderful conservation work together with well chosen animals. It is fascinating to me that such creatures are well adapted for an unusual job and to work together with people to solve such big problems we have in the world.

Operant conditioning is useful for many different species and projects. Working with behaviour is a very reinforcing job.

Many studies have been done on the African Giant Pouched Rat. There are a lot of pros to working with such amazing animals and through their behaviour Apopo has discovered on the way, just how intelligent these creatures are. No wonder Apopo has chosen rats to do such important work. 

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