Innovative research reveals the potential to train untamed predators to target unfamiliar alien species

For thousands of years, humans have trained domestic animals to assist with various tasks. But can we also train wild animals to aid in conservation efforts? While wild animals can be taught to recognize predators, avoid toxic food, and stay away from humans, there are few examples of using classical learning techniques to train free-living animals to benefit their ecosystem. However, a newly published study in Biological Conservation demonstrates that it is possible. In this study, wild Australian native predatory rats were trained to recognize and prey on an unfamiliar species of cockroach. The training proved successful, as the predation rates by the rats increased during a simulated cockroach invasion.

The article also discusses the growing number of alien species due to global trade. While some alien species have minimal impact on their new environment or even positively affect the ecosystem, many others have devastating effects on biodiversity and agriculture. The success of alien species in new environments is not well understood, but one reason for their failure is the resistance from native species. However, native species can only resist if they can respond appropriately, which may not be the case if they have never encountered the invaders before.

The study aimed to determine if the learning process of native predators could be accelerated by exposing them to the scent of a novel prey species paired with a reward. Native bush rats were used as the model predator, and speckled cockroaches were chosen as the alien prey species. The rats had no prior experience with these cockroaches since they do not live in Sydney and its surroundings. The training involved placing a metal tea strainer with the cockroach smell and dead cockroaches as a reward at specific sites. Cameras were used to observe rat behavior, and the training stations were moved periodically to prevent association of the reward with a specific location.

After the training, a simulated invasion was conducted at all sites using dead and tethered cockroach “invaders.” The survival rates of the cockroaches were compared between sites with trained and untrained rats. The results showed that cockroach prey in training sites were 46% more likely to be eaten than prey in non-training sites. The number of cockroaches eaten during training also predicted how many were eaten during the invasion. To ensure that the training process did not attract more rats to the training sites, cameras were used to compare rat visits using a peanut oil attractant. There was no difference between training and non-training sites.

This study is the first to train free-living predators to hunt species they have never encountered before. It highlights the potential for training native species to combat biological invasions. Additionally, it contributes to the growing evidence that training animals can be beneficial in addressing various problems, such as birds picking up litter and rats detecting landmines.