Sika deer with macaque monkeys

The southern island of Yakushima is Japan’s wettest region with precipitation ranging from four to ten meters! The island is also home to 150 bird species, 15 species of reptiles and almost 2000 species of insects. Among the sixteen mammal species are the Sika deer, also known as the Japanese deer, and macaques [see notes].

In a fascinating study and one of the best examples of interspecies communication between animals, scientists observed the Sika deer eavesdropping on macaques’ feeding call in order to find food! 

Interspecies Communication

What exactly is interspecies communication? It is the communication between different species of animals. Communication may be done visually through sound, body language or even odors. There are two main kinds of interspecies communication: mutual communication and parasitic communication.

Mutual communication is a form of symbiotic communication where both species benefit by cooperating with each other. As an example, the two species – Diana monkeys and Campbell‘s monkeys are both hunted by leopards. If one of them spots a leopard in the grass, it will send out an alarm call that warns the other species that there is a leopard lurking around. Then, the two species will position themselves near the leopard to let it know that it has been spotted.

Parasitic communication or eavesdropping, is a communication where one species benefits while the other is harmed because of unequal sharing of information. The interaction between the Sika deer and macaques as you will see is an example of parasitic communication where the deer benefits by intercepting feeding calls from monkeys. The monkeys however are harmed as they lose their food.

The Experiment

A team of scientists from Kyoto University conducted an investigation to find out how macaque monkey calls affected the behaviour of Sika deer. They found there were many common foods that the deer and macaques ate -- one of which was a fruit from the Camphor tree. They then recorded the calls macaques would make when feeding on the camphor tree. When they played the macaque calls, they noticed that the deer gathered in the area of the calls. There were more deer gathered in the area during the call than when it was silent.

Their next step was to play the macaques’ feeding call for fruits that only the macaques ate. They noticed that the deer did not respond when the feeding call was different and would not benefit them. The Sika deer had developed an uncanny ability to recognise the feeding calls of macaques and use them to find food.. Sneaky fellows indeed!

We could not find a video on interspecies communication; however here is a fascinating one on dolphin talk!