Scientists in Tanzania have trained rats to help detect illegal wildlife products being smuggled out of the country. The rats have learned to recognize the smell of these items, and can alert their handlers when they find them. The program is still being tested, but the method could help protect some endangered animals.
Illegal Wildlife Trade
Illegal wildlife trade – buying and selling material from endangered animals – is a huge international problem. It’s against the law. But it’s also a big business, which generates as much as $23 billion a year. Poaching animals, collecting their skins, horns, tusks, or other body parts, and selling them is a serious threat to many endangered animals, and even some kinds of plants.
Stopping illegal wildlife trade is hard. People who smuggle these products often hide them in tricky ways. They might paint an elephant tusk black, or try to make pangolin scales look like candy or chocolate. They might hide the products in a false bottom in a box. Often, they try to cover the smell of these items with other things that have strong smells, such as coffee.
(Source: D’Cruze et al. (2018) [CC BY 4.0], via Wikimedia Commons.)
Sadly, many of the countries these animal products come from are poor, so there’s not a lot of money to spend on catching the criminals.
A group called APOPO thinks that African giant pouched rats might be able to help.
African giant pouched rats are the largest rats in the world. They measure up to three feet (one meter) long (tail included), and weigh about three pounds (1.4 kilograms). Their name comes from the special pouches in their cheeks where they store food.
(Source: Apopo.org.)
These rats are clever. They learn quickly, and have a strong sense of smell. In the past, these rats have been used to find land mines, sniff out diseases, and help search for people after earthquakes.
The rats are trained using food rewards. They are first taught to stick their noses into a hole. Next, the scientists train them to identify certain smells. Finally, the rats are taught about smells they should ignore – smells that might be used to cover up the smell of the wildlife.
When the rats are working, they wear special vests. If the rat detects one of the smells it’s looking for, it grabs a little ball on its vest and pulls on it. This action sets off a beeping sound so that the rat’s handlers can come investigate.
(Source: Apopo.org.)
In a recent study, eight rats were successfully trained to identify four target smells: elephant tusks, rhino horns, pangolin scales, and African blackwood (a tree used in musical instruments). They were taught to tell these smells apart from 146 other smells that they learned to ignore. The rats remembered the smells, even after months.
Last year, the rats were tested at the Dar es Salaam seaport in Tanzania, a busy international port. The scientists had hidden illegal wildlife products in several containers. The rats were able to locate over 83% of the hidden items, even when there were other smells to cover up the target smells.
(Source: Apopo.org.)
Currently, dogs are commonly used to search for illegal wildlife products. Dogs do well in open areas where there’s a lot of ground to cover. The rats won’t replace dogs, but they could definitely help out – especially in places where dogs can’t go, like tight spaces inside shipping containers.
The results suggest that these clever, vest-wearing rats could be an important tool in the fight against illegal wildlife trade.
Did You Know…?
There are several other reasons African giant pouched rats are a good choice for fighting illegal wildlife trade. Compared to dogs, rats are cheaper, faster to train, and easier to support. Normally, dogs work with a single handler. Rats are flexible, and don’t mind working with different people.