Smart beings

Intelligence is not an attribute bestowed on the humans alone. Animals too have a mind of their own and use it to find food and protect themselves, writes Atula Gupta

‘Kaalia’ the crow might have outsmarted the crafty crocodile, ‘Doob-doob’ innumerable times in the comic world, but in the real world, it seems like the crocodile might easily outwit the bird. Scientists have discovered that reptiles like the Indian Magar Crocodile and the American Alligator use tools, specifically sticks to lure birds into their trap.

What this latest discovery affirms is the fact that intelligent use of tools is not restricted to humans or primates alone but it is a characteristic of all the brainy species regardless of their shape and form.

Tool use in the animal world has always garnered interest of scientists and laymen. Some look at it as an additional proof of the falsity of the claim that humans are the most intelligent living forms in the world, while others marvel at how little we still know of our planet and the species that live with us.

From chimps to dolphins, elephants to kea birds, octopuses to rodents, today there is no dearth of examples of land, water or air animals that use tools dexterously to ease their work at hand and more commonly, to obtain food.

Bottlenose dolphins in Shark Bay, Australia, carry marine sponges in their beaks to stir ocean-bottom sand and uncover prey, spending more time hunting with tools than any animal besides humans. Chimps are able to chisel spears to hunt other primates for meat.

Crows are extraordinarily adept at crafting twigs, leaves and sometimes their own feathers into tools. Anecdotes suggest elephants, the most intelligent animals in the world, can intentionally drop logs or rocks on electric fences to short them out and plug up water holes with balls of chewed bark to keep other animals from drinking them.
Octopuses can use coconut shells as armour and carry heaps of these shells upon their head for later use.

But what is the purpose of a stick balanced on a crocodile’s snout? It is this puzzle that researchers solved and were surprised to find that it was a lure of a reptile that cannot fly, to catch a prey that could.

Bird bait

Magar crocodiles (Crocodylus palustris) in India and American alligators (Alligator mississippiensis) in the USA have often  been observed to have sticks or twigs on top of their snouts.

The scientists found that rather than being an accidental occurrence, this was a deliberate ploy of the crocs. They put sticks on their snouts and remained submerged in water near egret and heron colonies. When the nest building birds, spotted the sticks and approached them unaware of the dangers lurking under water, the crocodile found the chance to grab its prey.

What the researchers also observed was that the crocodiles’ behaviour was not random but coincided with the nesting and breeding season of the egrets and herons usually in the month of March and April.

It was also observed in animals that lived near rookeries.
Therefore, the reptiles displayed intelligence in specifically choosing an object that could help them achieve a goal and that too at a precise time when they knew their prey would need the sticks for creating nests.

The researchers add that the behaviour becomes all the more interesting because floating sticks are extremely rare in the pools, especially at the time of year concerned. This is because the local trees – baldcypresses and water tupelos – don’t shed twigs, and also because the nesting birds rapidly remove floating sticks for nest-building. Thus, what the crocs are displaying is a purposeful act, where they are deliberately looking for the sticks, and using them to target preys.

This kind of behaviour displayed by the reptiles is called as baiting behaviour and has also been observed in Green herons (Butorides virescens) and other species of birds and animals. The herons use feathers, twigs and even berries and bits of bread to attract fish.

The study authors are sure that because the baiting behaviour has been observed in two crocodiles species separated by continents, it can be presumed that the behaviour is probably widespread and common among the animals.

Measuring intelligence

Animal intelligence is often underrated by us, firmly adhering to the theories of evolution that regard humans as a complex living form, with a more developed brain and thus more intelligence. However, there are many scientists that are questioning this viewpoint.

According to Maciej Henneberg, a professor of anthropological and comparative anatomy, humans have misunderstood animal intelligence."Animals offer different kinds of intelligences which have been under-rated due to humans' fixation on language and technology. These include social and kinaesthetic intelligence.

Some mammals, like gibbons, can produce a large number of varied sounds – over 20 different sounds with clearly different meanings that allow these arboreal primates to communicate across tropical forest canopy. The fact that they do not build houses is irrelevant to the gibbons," Henneberg added.

Even in crocodiles, apart from the recent revelation of use of tools, the sly use of neighbours to protect the young has been often observed. Nile crocodile mothers have been known to protect their eggs from numerous thieves, such as the giant Nile monitor, by enlisting the aid of nesting curlews known as thick-knees – that share the same marshy habitat.

Perfectly camouflaged nesting curlews intimidate marauding Nile monitors in turn enjoy the crocodiles' protection from hippopotamus and other visitors.

If intelligence is not about technological wizardry but the ability to acquire and apply knowledge and skills, the crocodile, the octopus or the human are all definitely in the same league.