And why is tool use in animals important?
My initial, oh-so-pithy response to this question is “Why, humans of course!” But that’s simply because I never tire of reminding humanity of its membership in the Animal Kingdom (or “kingdom Animalia” if you’re scientifically inclined). Joking aside, humans and our primate kin are an excellent place to start a discussion of tool-use.
It’s common knowledge that our closest relatives, chimpanzees, engage in tool use. Tanzanian chimps, for instance, use grass and twigs to pull ants from their holes. Interestingly, the specifics of tool use change among different chimpanzee populations, indicating a strong cultural component to this behavior. More recent research (2007) showed that chimps in the Fongoli savannah sharpen sticks to use as spears for hunting. It is impossible to miss the echoes of our past in these observations.
A video of chimpanzee tool use:
Moving just a bit further away from ourselves in the primate lineage, the first reports of tool use in wild western gorillas came from a paper in 2005. According to the researchers themselves: “We first observed an adult female gorilla using a branch as a walking stick to test water deepness” and “we saw another adult female using a detached trunk from a small shrub as a stabilizer during food processing. She then used the trunk as a self-made bridge to cross a deep patch of swamp.” What sets these observations apart is that most tool use in animals is oriented around the acquisition of food, not in locomotion.
Finally, hooded monkeys, most primitive of our examples, exhibited similar techniques when confronted with a laboratory challenge. They were given yogurt in narrow plastic tubes; the tubes were too small for their fingers, and fastened firmly to a table. The monkeys ended up using pieces of wood as rudimentary (but effective) spoons. (This example, admittedly, begs the question of whether or not hooded monkeys would display such behavior in the wild, without a lab setting designed to facilitate tool use.)
We have a tendency to focus on the tool-use behavior of primates, probably because it illuminates our evolutionary past, but we primates do not have a monopoly on tool use, as previously thought.
Cetaceans (Whales & Dolphins)
For my money, cetaceans are the group mostly likely to surprise us as we continue to investigate intelligence and culture in the animal kingdom. It is generally agreed-upon that whales and dolphins are an intelligent group, as demonstrated by the complexity of whalesong and the eminent trainability of dolphins. However, perhaps simply because it is difficult for a terrestrial species to study a marine species, our understanding of cetaceans lags behind that of primates.
A bottlenose dolphin:
In 2005, researchers discovered bottlenose dolphins in Shark Bay using marine sponges as a foraging tool. Beyond simply recording this striking example of tool use, they argued that “genetic and ecological explanations for this behavior are inadequate”—that is, this behavior must be culturally transmitted, representing “the first case of an existing material culture in a marine mammal species.”
It’s true that opposable thumbs come in handy (pun!) when using/making tools, but the dexterity of an elephant’s trunk is not to be dismissed. They have been reported using sticks for various purposes, such as removing ticks. They’ve been repeatedly recorded throwing objects as weapons and during play. Elephants have even been seen to disable electric fences with a well-placed rock of log. This page from The Nature Institute offers a fascinating list of elephant anecdotes, including my absolutely favorite:
“Many young elephants develop the naughty habit of plugging up the wooden bell they wear around their necks with good stodgy mud or clay so that the clappers cannot ring, in order to steal silently into a grove of cultivated bananas at night. There they will have a whale of a time quietly stuffing, eating not only the bunches of bananas but the leaves and indeed the whole tree as well, and they will do this just beside the hut occupied by the owner of the grove, without waking him or any of his family.”
(I hope I’m not the only person inclined to mutter “clever girl” after reading this.)
An African elephant:
Ornithologists these days love turning the pejorative “bird brain” on its head by pointing out that our fine feathered friends can provide some of the best examples of animal intelligence yet recorded, including (but not limited to) tool use.
Egyptian vultures are well-known for their egg-smashing habits. Other species of bird will drop eggs onto rocks to open them, but this isn’t considered tool use – what “tool” are they using? Gravity? Egyptian vultures pick up stones and chuck them at a given egg until it breaks. Granted, their accuracy is poor, but they make up for it with good ol’ grit—they won’t stop until they win their prize.
The woodpecker finch, one Darwin’s legendary finches, is not as well-equipped, physically, as its namesake. Woodpeckers have long, barbed tongues to pull grubs from branches – these finches have no such specialized tongue. Instead, they pluck a spine from a nearby branch and use it as a makeshift crowbar to pry grubs free. Most impressively, these birds have been reported shortening overlong spines to make them more manageable. It is one thing to make use of an object as it exists in the environment; it is another to modify that object to better-suit one’s needs.
The corvids (crows, ravens, jays, and their kin) are well-known to ornithologists as a generally intelligent family of birds (even the American crows we generally take for granted). But the all-stars of corvid cleverness are the New Caledonian crows (Corvus moneduloides), residents of a remote island cluster in the South Pacific roughly 750 miles east of Australia. Like chimps, they use tools crafted from sticks to forage for invertebrates. With four different types (minimum), an involved manufacturing process, and complex shapes, these tools may represent the epitome of animal tool-creation.
A common raven, member of the corvids:
The parallels between these crow’s tool-making and that of chimpanzees—the tools themselves, the materials used, and their purpose (to collect invertebrates) are all similar—coupled with their remote evolutionary origins (crows and chimps are not closely related) has led to a least one paper proposing that these cognitive abilities, of which tool use is but one facet, are a result of convergent evolution. That is to say, similar socioecological problems faced by chimps and these crows resulted in independent evolution of their similar cognitive abilities; chimp tool use is analogous to crow tool use.
Our final stop on this tour of animal tool use has been very recently added: the veined octopus (Amphioctopus marginatus) of Indonesia has been recorded collecting discarded coconut shells to use as portable protection. They don’t simply hide beneath them, however – they gather, move, and generally manipulate them to the extent that they qualify as tools, and not simply convenient objects for shelter.
A video of the ‘stilt-walking’ behavior these octopuses use to carry coconuts:
The definitions of tool use inevitably ends up a bit ambiguous, like many terms of any weight in modern biology. Suffice to say, scientists are comfortable calling this behavior tool use. I was skeptical when I first heard the story on the morning news, but the words of researcher Mark Norman (as quoted in this TimesOnline story), put me at ease: “There is a fundamental difference between picking up a nearby object and putting it over your head as protection versus collecting, arranging, transporting — awkwardly — and assembling portable armour as required.”
This finding is the most contrary yet to the previously-held belief that tool use was a uniquely human characteristic. By extension, it makes a strong case for the theory that intelligence has evolved multiple, independent times in the animal kingdom, even within lineages as ‘primitive’ as the mollusks.
Ultimately, the study of tool use in animals continues along the same humbling trajectory as much of scientific progress. Consider astronomy, which was revealed our place in the universe to be ever-smaller – with modern multiverse theories, our universe may not even be unique. Likewise, over the course of this answer, we’ve shattered the human monopoly on intelligence, the mammalian monopoly on intelligence – even, with the veined octopus, the vertebrate monopoly on intelligence.
This all, of course, begs several fantastically weighty questions, and allows me to cap this answer with a real mind-bender: what, then, is it that makes us human?
SOURCES & FURTHER READING
Awesome answer, when in your life did you start becoming so fascinated with animals and want to be a zoology major?
Thanks! I grew up on the only forest we have in my hometown — a modest tract of land shared between three cities and protected by the state. I can’t remember a time when I wasn’t interested in wildlife and the natural world.
It seemed a forgone conclusion that I would end up a zoology major. At the moments my dreams of being a field researcher are on hold as I work on being a science/nature writer instead.
Gorillas, Chimpanzees, Orangutans, Capuchin monkeys, New Caldoneon Crows, Woodpecker Finches, Bottlenose Dolphins, Elephants, Sea Otters, and Veined Octopi are all among the animals that have been observed using some sort of tool.
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