Keeping in touch
Mammals may not talk like us, but they do communicate with other animals – belonging to same species and others as well – through some ingenious techniques. In fact, they communicate so often, that if we converted these messages into signals which we can perceive, the forest would feel like one overcrowded chat room. From a simple growl to a secretive scent left behind, here is a look at some of the communication methods practiced by mammals in the wild.
Communicating’ is an easy activity to follow for most of us. Even if it is not a face-to-face delivery of message, in today’s day and age, technology enables us to communicate with almost anyone, anywhere. Wireless technology makes sure you can get in touch with someone instantly, no matter where you are. An update on a social media site is potentially there for the entire world to read. A ‘virtual’ face-to-face conservation in real time is also possible, even if the person is thousands of miles away from you. But in the absence of this manmade technology, animals have developed some amazing strategies to stay in touch with each other.
Super senses – some simply unfathomable to us – such as incredible hearing, sharp vision and sensitive smelling senses are the strategies animals make use of. Why, there are some animals that can hear inaudible sounds easily over a few miles, smell the faintest of scents that was probably left weeks ago and even detect movements simply through vibrations felt in air! These super senses that animals have been gifted with and the amazing techniques that they have developed, help them share, send and receive messages; more often than not, without us realising what is happening around us.
Communication through touch is a very important method for several species of mammals. Play fighting among cubs, kittens or pups, not only develops their hunting skills, but also helps establish dominance among them. A dominant young one is benefitted with first dibs on the food provided by the parents, and usually turns out to be the healthiest of the lot. Cats rub their faces when they meet each other, and sometimes, their entire bodies to greet one another; rubbing faces is a strategy used by otters as well. The generally solitary animals use this method to establish relationships, while social animals do it to strengthen their bonds.
Large cats like lions scratch on tree trunks to mark their territory. Image : Bhavya Joshi
Touching as means to communicate is probably most complicated among primates. Monkeys establish their social ranks by grooming each other, an activity that also aids in the removal of dead skin and parasites. The strong bond which a monkey mother and her baby share is evident from the way she holds, cuddles and comforts her young one.
Several species secrete chemicals through their urine or scent glands. These chemicals are known as pheromones and are used to communicate with members of the same species for several purposes, such as, marking territory, finding potential mates and advertising one’s self.
Female elephants, for example, secrete pheromones from glands located in the temporal region when ready to mate. Even male elephants are known to secrete this pheromone when ready to mate, while fighting with other bulls or when excited. Deer and antelopes have scent glands located in the front of the eyes. The pheromones secreted from this gland are rubbed against grass blades or twigs of shrubs and are used to mark a home range. Several animals like lions and deer, smell the urine of the female to judge her readiness to mate.
The flehmen response — when the upper lip curls and front teeth are exposed — is a sign indicating that an animal has smelled a chemical signal left by another of its species. Image : Anup Deodhar
Large cats scratch on tree trunks to mark their territory. Scratching on trees not only leaves a visible signal, but also the olfactory signals emitted from the glands located on the pads. Image : Rajesh Mkrish
Large cats spray their urine on tree trunks, clumps of grass and boulders to mark their territory. The mark left in the form of a scent is a complex signal – passing on personal information such as the age and sex of a large cat to a compatriot cat that might come sniffing around. But while chemicals are used only as messengers in all these cases, there is one mammal that takes chemical signals to the level of warfare. The Bengal slow loris is unique among mammals for having a toxic bite. Toxin is also secreted through special glands located on their arms, which is carefully applied on the fur of a baby loris to deter predators.
Body postures communicate a lot in Canids; exposing canines and flat ears indicate aggression. Image : Ramakrishnan Aiyaswamy
All mammals make sounds, which is inevitably a mode of communication. These sounds vary— from the faint squeaks of mice to the loud roars of big cats. While some mammals show very little variation in their vocals, some others demonstrate a huge diversity, with each sound possessing a different meaning. This has led several biologists to believe that some mammals actually have a language of their own.
Cats greet each other by rubbing their faces and bodies against each other, which helps in establishing bonds. Image : Rajdeepsinh Jadeja
One such group of mammals is the dolphins. Through a variety of squeaks and clicks, dolphins continually keep on speaking to each other. But besides communication, they also use sound to locate their prey. Recent studies have indicated that dolphins might even be capable of sending private messages to an individual member of their pod, without other dolphins in the vicinity realising what it says. Their distant cousins, the whales, are known to make long, resonating, and often soothing sounds, known as ‘songs’. The long and sweet songs of the Humpback whales are particularly famous. In water, these sound waves travel long distances and often, a whale not even in distant sight is listening and responding back.
Dolphins probably have one of the most sophisticated languages in the animal kingdom (humans included). Image : Joshua Barton
In social animals, such as Dholes, physical contact also helps in establishing hierarchy. Image : Sheshadri Vasan
Another group of mammals with a complex vocalisation library are monkeys. In fact, most species have specific sounds designated to specific things, which is as good as assigning a certain word for every object. One good and extremely common example of this is the crackling bark given out by the grey langurs, which literally translates to ‘danger’. We commonly call such sounds alarm calls, and these are extremely important in tracking big cats. Even deer species like Sambar and Spotted deer have their own vocalisations for sounding an alarm. Not only do monkeys understand the deer’s ‘language’ and vice-versa, but this call is also a message sent to the predator (most often a big cat that relies on ambush) that it has been spotted.
Foxes live in pairs for most of their lives and physical contact between the partners is very important for a successful and long-lasting pairing. Image : Vickey Chauhan
Stop, look, talk!
Most mammals have good eyesight and hence, visual signals play an important role in communication. One of the most expressive groups of mammals is the family of dogs that communicate through body postures. While a raised spine and flaring canines signals aggression, flattened ears, a tucked tail and a flattened body indicates submission. A Sambar stomps its front leg and raises its tail when it feels the presence of a predator, thus alerting all those who can see the deer.
Some mammals change their body colours to display their readiness to mate. There are very few Indian mammals which do this, and the Desert or White-footed fox is probably the only one which shows a prominent change in coat colour. A male deer’s antlers also serve the same purpose, impressing the females and warning rival males at the same time.
Image : Ramakrishnan Aiyaswamy
Image : Anuroop Krishnan
Primates employ a very sophisticated communication system, which uses visual signals, touching and olfactory signals. Grooming (above) forms a very important part of their daily routine, ascertaining bonds within a troop. Flaring of canines (down) symbolises aggression.
Sometimes, in addition to leaving chemical signals to proclaim a territory, visual clues also have to be left to ascertain this claim. Apart from leaving their scent to mark out a territory, dung piles are created by male antelopes over the periphery of the said area as an additional signal for those ignorant to the scent markings. A male Blackbuck also struts with his head held high and horn pointing backwards to make sure no one misses out on his claim. Tigers and lions scratch at tree stumps and leave behind deep scars to warn off those foolish enough to ignore their scent markings.
Warning signals or alarm calls given by prey animals not only warn others of their species, but also other prey animals around them. A raised tail (above) and the warning calls are signals which help even humans to track down predators. Images : Pranad Patil
On vibration mode
A male Nilgai will use aggressive body postures to ward off rival males entering its territory during the mating season. Image : Dharmesh Patel
Elephants have a keen sense of hearing and using their big ears, they are able to detect some of the faintest sounds. And they don’t just use their ears to listen, but their feet too! Their extremely sensitive feet are able to pick up vibrations created by elephants stampeding several kilometres away. These long distance signals help elephants within a herd find each other and also help in finding a mate. Elephants are also suspected to feel vibrations created by water through their feet, which helps them in locating water bodies over long distances.
Elephants have some of the sharpest senses in the animal kingdom. They are capable of picking up the faintest of vibrations from the ground and also smell over incredibly long distances. Image : Pranad Patil
Tip of the communication iceberg
Be it subtle or outright brash signals, communication is of utmost importance for any individual mammal belonging to any species. The very survival of an individual may depend on the ability to communicate effectively with members of the same species, as well as members of other species. Failure to perceive an alarm signal could most certainly spell death for a prey animal. Similarly, not understanding the signals left by another predator could land even an apex predator in trouble.
Communication in mammals has evolved over millions of years. During this period, mammals have developed some fascinating ways to stay in touch with each other. It is a complex tactic and is still an evolving phenomenon. We have probably just understood some of the simplest methods in which mammals communicate, and in all probability, many more fascinating and unique ways of sending and receiving messages are yet to be discovered.
This article first appeared in the March 2015 edition of Saevus magazine.