Tool use by animals



Some animals, especially primates, use tools to perform simple tasks such as getting food or grooming.

Types of tools
There are some different definitions of a tool, such as:

"''An object that has been modified to fit a purpose' or 'An inanimate object that one uses or modifies in some way to cause a change in the environment, thereby facilitating ones achievement of a target goal'."

- Hauser, 2000

"the use of physical objects other than the animal's own body or appendages as a means to extend the physical influence realized by the animal"

- Jones and Kamil, 1973

The most common are sticks or bits of stone.

Uses
Tool use implies an animal has knowledge of the relationship between objects and their effects.

If an object is placed out of reach on a towel that itself is in reach, dogs and children will pull the towel to bring the object closer to them. But does this show knowledge about the nature of the world (declarative memory) or recall of rules already learnt (procedural)?


 * Sticks can be used to break into termite nests for food or even to fight rivals. They are sometimes used for grooming.
 * Stones can be used, again, to fight rivals. However, they may also be used to carve bits of wood by more intelligent animals.

Some species, such as the Woodpecker Finch of the Galapagos Islands, use particular tools as an essential part of their foraging behavior. However, these behaviors are often quite inflexible and cannot be applied effectively in new situations. Several species have now been shown to be capable of more flexible tool use. A well known example is Jane Goodall's observation of chimpanzees "fishing" for termites in their natural environment, and captive great apes are often observed to use tools effectively; several species of corvids have also been trained to use tools in controlled experiments, or use bread crumbs for bait-fishing.

Primates
Research in 2007 shows that chimpanzees in the Fongoli savannah sharpen sticks to use as spears when hunting, considered the first evidence of systematic use of weapons in a species other than humans. It has also been observed in the 1970s that some chimpanzees/bonobos use sticks as probes to collect ants and termites. Also they have been observed cutting down the stick with their fingers and teeth so that it can fit into a hole in the ants' nest. They have even been observed using two tools, a stick to dig into the ant nest and a 'brush' made from grass stems with their teeth to collect the ants. In west Africa chimpanzees have been observed banging nuts against a stone in order to crack it. Some troops use another stone whilst others use wooden clubs (heavy sticks). In one troop of chimpanzees it was observed that a female was using a stick to break into a bee hive to acquire honey. In an experiment a group of chimpanzees were presented with a model leopard with a moving head. There was soon commotion as leopards are one of the chimpanzees' predators. They were then observed clubbing the model with heavy quarterstaffs (fallen trees and/or branches). They continued doing this until the moving head had fallen off.

Gorillas have been observed to (as shown above) use sticks to measure the depth of water.

Orangutans have also been observed to use sticks to measure the depth of water. It has also been observed that Orangutans in Sumatra use sticks to acquire seeds from a certain fruit. This is because the lining of the inside of the fruit has hairs that sting. On the island of Kaja a male Orangutan was observed using a pole to acquire fish from a net after observing local humans spear fishing. .

Capuchins have also been observed banging nuts between two stones in order to crack it. They have also been observed using stones to crack into shells. In captivity Capuchins have been observed during experiment to make flint knives after banging a piece of flint against the floor until it broke and using the smaller, sharper pieces to cut into a box with fruit. Some scientists believe that this (the above) isn't because of some higher intelligence in Capuchins but an interesting side effect of their aggressive and destructive nature.

Birds
Many birds have been shown as capable of using tools. By Jones and Kamil's definition above, an Egyptian vulture dropping a bone on a rock would not be using a tool since the rock cannot be seen as an extension of the body. However the use of a rock manipulated using the beak to crack an ostrich egg would qualify the Egyptian vulture as a tool user. Many other species, including parrots, corvids and a range of passerines, have been noted as tool users.

New Caledonian Crows have been observed in the wild to use stick tools with their beaks to extract insects from logs. While young birds in the wild normally learn this technique from elders, a laboratory crow named "Betty" improvised a hooked tool from a wire with no prior experience. The Woodpecker Finch from the Galapagos Islands also uses simple stick tools to assist it in obtaining food. In captivity, a young Cactus Finch learned to imitate this behaviour by watching a Woodpecker Finch in an adjacent cage. Crows in urban Japan have innovated a technique to crack hard-shelled nuts by dropping them onto cross walks and letting them be run over and cracked by cars. They then retrieve the cracked nuts when the cars are stopped at the red light. Striated Herons (Butorides striatus) and Hooded Crows (Corvus cornix) use bait to catch fish.



Cetaceans
, scientists have observed limited groups of Bottlenose Dolphins around the Australian Pacific using a basic tool. When searching for food on the sea floor, many of these dolphins were seen tearing off pieces of sponge and wrapping them around their "bottle nose" to prevent abrasions.

Elephants
Elephants show a remarkable ability to use tools, despite having no hands. Instead, they use their trunk like an arm. Elephants have been observed digging holes to drink water and then ripping bark from a tree, chewing it into the shape of a ball, filling in the hole and covering over it with sand to avoid evaporation. The elephant later went back to this spot for a drink. They also often use branches to swat flies or scratch themselves. . Elephants have also been known to drop very large rocks onto an electric fence to either ruin the fence or cut off the electricity

Mustelids
Sea otters have been observed using stones to hammer abalone shells off the rocks. They hammer at a rate of 180 blows per minute and do it in three dives.