published on 7 November 2017 in life
Beyond speech: the language of animals
Telegraph, telephones, radio, television, cell phones, internet… Communications have played a leading role in the last century and continue to shake up the world we live in, changing both the way in which we interact and society. According to anthropologists, humans have been communicating with speech for at least 100 thousand years, even though development of the conditions required to utter elaborate sounds probably dates back to long before (over 3 million years ago). It was in fact when humans began to stand upright that the larynx began to descend, and development of the hypoglossal nerve allowed humans to control their tongue muscles in an increasingly more sophisticated way.
This characteristic – the ability to speak – and the importance we give to verbal messages, whether they are in written or oral form, often leads us to believe that animals, who do not use verbal language, are unable to communicate. Yet speech is not the only way of transmitting information. From humans to insects, from fish to mammals, the strategies that animals use to exchange messages are very numerous and involve sight, touch, smell, hearing and sometimes even more than the five senses that we know well.
Messages, senders and recipients
Communication may take place in various ways: between two individuals of the same species, for example, a courting song between two birds; between a sender and more than one recipient of the same species, as for example, in the case of a warning whistle of a marmot; or between individuals of different species (interspecific communication), as in the case, for example, of a cat whose fur bristles when it feels threatened by a dog.
When we talk of animal communication, it is very easy to fall into the trap of anthropocentrism, and therefore of believing that we understand everything that the other species “say” to each other or interpreting the messages using “our own codes”. We cannot presume that we are able to intercept all the signals that other animals transmit to one another and, on the contrary, we must be aware that we probably miss many conversations that take place right under our noses!
What scholars, and in particular ethologists, the scientists who study animal behaviour, know for certain is that some of the most important reasons for which animals communicate with each other regard courting, defence of territory, warning of danger, procuring food and so forth. Starting from these assumptions, then, we can begin our journey through the great vocabulary of the animal kingdom.
A male bird of paradise courting a female with a veritable dance.
Using our eyes, we can see gestures, facial expressions, movements, colours, light. For example, young male chimpanzees show that they accept their submission towards a dominant male by expressing their fear, while a dog that wants to show anger will bare its teeth.
However, going back to the bird world, let us think of herring gulls: they have a red spot on their beaks and, after they have been out hunting for food for their chicks, they return to the nest and show the spot by tapping their beaks on the ground. In this way, the parent bird encourages the chick to peck at their beaks where the red spot is, prompting regurgitation and, therefore, feeding the chicks.
On the subject of coloured body parts, another example of intraspecific communication is that of the olive baboon: females of this species are in fact able to change the colour of their genital area to let males know that they are ovulating. When the time is right for mating, the female’s anogenital area swells and turns a bright red/pink, an invitation to members of the opposite sex to mate with her.
Numerous animals change colour to send out messages. Male cuttlefish, for example, during courting when other males are present, take on a typically male colouration on the part of their bodies exposed to the female. At the same time, they take on a typically female colouration on the side facing their rivals, to deceive them and distract them from the “real female”.
Another strategy to deceive predators, giving them misleading information, is bioluminescence. Some squids, for example, are able to emit a luminous cloud which, in the event of attack, distracts the predator from the real prey, which in the meantime thus gains the time to escape.
Bioluminescence may also have another function: for example, pyrosomes, animals that live in colonies known as zooids, use light to synchronise movement and thus stimulate propulsion.
Another method of communication involving sight is that of movement, often in meticulously repeated sequences that are sometimes accompanied by sounds, the result of which may appear to our eyes an actual dance. Some birds (including birds of paradise) dance, bees dance to indicate the location of flowers or places suitable to establish hives, even some fish dance, to identify females or to drive rivals away.
Mating, danger, calls for food, can all be signalled by audible sounds. The seductive song of some birds, crickets or cats are well known and scientists have also discovered that other species, like the vervet monkey, are also able to send out diversified danger signals depending on the threat that they face. In the case of this primate, the danger signal varies according to the type of predator sighted.
Sounds may be produced in the form of vocalisation or by movement and these methods are typical of very many animals, from rattle snakes to whales, from bats to millipedes. The latter, for example, in order to produce sounds and, in any case, communicate, use what is known as stridulation, which takes place by rubbing together certain body parts and is typical of many reptiles and insects, like cicadas.
Not all sounds issued by animals can be heard by humans: our ears, for example, are unable to hear ultrasounds, which are very commonly used between dolphins, insects, bats and even some species of squirrels!
Sense of smell
One of the oldest strategies for communicating, however, is through sense of smell, also known as “chemical communication”. It is no chance that some animals, for instance dogs, communicate by chemical signals, for example to capture the attention of their partners, to clearly express fear, to mark their territory. Since dogs have the instinct to live in packs, they leave traces of themselves – through their urine, faeces or other body odours – to communicate with their fellow dogs. It is not just a matter of signalling their passage through territory: the information that these animals are able to transmit to each other may also regard their emotions or state of health when leaving the message.
Insects too, above all social ones, often use chemical communication. Ants are able to recognise members of their own colony through emission of particular combinations of CHC (cuticular hydrocarbons). Based on identification of these molecules, ants perceive the identity of the individual before them.
Touch and other strategies
Touch too is obviously a means of communication for animals. During courting, contact between partners may signal the intention of the male to mount the female. A male kangaroo, before mating, grabs the female’s tail, but other forms of contact may for example favour communication to coordinate group movement, or to signal integration of an individual into a pack.
Yet, communication in the animal world goes well beyond the five senses, as we are used to considering them. Recent studies on elephants have shown that these animals are able to generate small earthquakes to communicate at long distances through vibration of the ground. The trumpeting of elephants, besides spreading through the air, cause actual surface seismic waves that can be perceived by other specimens as far as 16 kilometres away.
Another very original system is the use of infrared radiation by snakes: during the course of evolution, in fact, these reptiles have developed the ability to intercept the heat signals that their prey unconsciously give off. Infrared radiations are recognised by snakes by means of special pits that allow the reptile to locate its prey very precisely.
In conclusion, beyond speech, television, internet and smartphones, animals have developed very many strategies for communicating and interacting. Many of these, like ultrasounds, are not perceived by humans, others appear to us as authentic art forms, that are in no way inferior to architecture, music and art as they are known to humans. From the dances of bees, to birdsong, from building of coloured and sophisticated nests to the synchronisation of movement in flocks or swarms.
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