Interspecies Communication - Mutualism

Mutualism

Cooperative interspecies communication implies the sharing and understanding of information from two or more species that work towards the benefit of both species (mutualism). Most research has found cooperative communication in prey animals whose alarm calls not only alert conspecifics but also heterospecifics. So far, most work has been found in primates. Redfronted lemur and sifakas have reciprocal recognition of one another’s alarm calls. The same has been found in West African Diana monkey and Campbell’s monkeys. When one species elicits an alarm signal specific to a certain predator, the other species react in the same pattern as the species that called. For example, leopards hunt on both species by capitalizing the elements of stealth and surprise. If the monkeys detect the leopard before it attacks (usually resulting in mobbing), the leopard will typically not attack. Therefore, when a leopard alarm call is given both species respond by positioning near the leopard signaling that it has been found out. It also seems that the monkeys are able to distinguish a leopard alarm call from, for example, a raptor alarm call. When a raptor alarm call is given, the monkeys respond by moving towards the forest floor and away from aerial attack. Therefore, it is not simply that the monkeys act upon hearing the alarm calls but rather they are able to actually extract particular information from a call. Increased vigilance obviously has its benefits since more eyes watching mean earlier detection of predators and lower risk of being eaten. Responses to heterospecific alarm calls are not confined to simian species but have also been found in the Sciuridae species: yellow-bellied marmot and the golden-mantled ground squirrel.

Whether heterospecific understanding is a learned behavior or not is also of interest. Ramakrishnan and Coss (2000) found that age and interspecies experience were important factors in the ability for bonnet macaques to recognize heterospecific calls. Macaques who were younger and exposed longer to other species’ alarm calls were more likely to correctly respond to heterospecific alarm calls. A key component of this early learning was the reinforcement of a predatory threat. That is, when an alarm call was given a corresponding threat had to be presented in order to make the association. Therefore, interspecies communication may not be an innate ability but rather a sort of imprinting that may have to be coupled with an intense emotion (fear) early in life. In fact, most interspecies communications reported typically involve an older animal taking care of a younger animal of a different species. For example, Owen and Mzee, the odd couple of an orphaned baby hippopotamus and a 130-year old Aldabran tortoise, display a relationship rarely seen in the animal world. Dr. Kahumbu of the sanctuary that holds the two believes that the two actually vocalize to one another in neither a stereotypical tortoise nor a hippopotamus fashion. Interestingly, Owen also does not respond to hippopotamus calls. It is likely that when Owen was first introduced to Mzee he was still young enough where imprinting could occur.