Tool use

Definitions of tool use vary across the literature, and that variation matters. A widely cited working definition treats tool use as the use of an external object to alter the form, position, or condition of another object, another organism, or the user itself, with the user holding or carrying the tool during or just before use. Other definitions are broader or narrower, and researchers often state explicitly which one they are applying. There is no single agreed line, so claims about whether a particular behaviour "counts" depend on the definition in play.

It helps to separate a few related ideas. Tool use is the observable behaviour. Tool manufacture — modifying an object before using it — is a further step that not all tool use involves. And the cognition behind a behaviour is a separate question again: using a tool does not by itself reveal what an animal understands about why it works. This guide keeps those layers distinct, describing what is seen and attributing interpretations to the research rather than asserting them as settled fact.

It is also worth resisting a "human-like technology" framing. Animal tool use is interesting on its own terms as a biological and behavioural phenomenon, and comparing it to human toolmaking as if along a single scale tends to obscure more than it reveals. Different species solve different problems in different ecological settings, and the behaviours are best understood in those contexts rather than as steps toward a human benchmark.

Among the best-documented cases is termite-fishing in chimpanzees (Pan troglodytes). Long-term field research, beginning with observations reported by Jane Goodall at Gombe in what is now Tanzania in the early 1960s, described chimpanzees inserting slender stems or stripped grass blades into termite mounds and withdrawing them with termites attached. In some populations the animals also modify the probes, for example by removing leaves, which is often discussed as a form of tool manufacture rather than simple object use.

Beyond termite-fishing, chimpanzees in different regions have been reported using stones or wood as hammers and anvils to crack nuts, and using leaves in various ways. A notable feature of this body of work is that tool repertoires differ between populations that are not obviously different in environment or genetics, and researchers have discussed some of this variation as socially learned local tradition — one of the lines of evidence behind the careful, restricted use of the word "culture" for certain animals. "Culture" in this sense means locally varying, socially transmitted behaviour documented in particular populations, not human civilisation.

These behaviours are striking, but the cautious framing in the research is deliberate. Observing a chimpanzee select and modify a probe shows skill and, in many studies, learning from others; it does not license claims about the animal's inner experience or about apes in general behaving identically everywhere. Tool use is not uniform across all chimpanzee populations, and findings from particular study sites or captive settings should not be read as universal.

New Caledonian crows (Corvus moneduloides) are among the most studied birds in this area. Field and laboratory research has documented these crows using sticks and crafting probing tools from plant material, including tearing and shaping pandanus leaves and, in some cases, fashioning hooked tools that they use to extract insect larvae from crevices. Controlled experiments have examined how individuals handle novel object-retrieval problems, and the findings are often discussed in terms of flexible problem-solving.

A few cautions are important. The most elaborate tool behaviours are documented in this particular species and some related corvids, and should not be generalised to all crows, all corvids, or birds as a whole. Experimental tasks are designed to probe specific abilities, and a successful result on one task does not establish a broad, human-style understanding; researchers are careful to distinguish what a bird does from what it may or may not represent internally. Different studies, and different individuals, can also give different results.

What the corvid work illustrates well is that tool use is not restricted to primates and has arisen in distantly related groups. That distribution is interesting precisely because it cannot be explained by close common ancestry, and it is usually framed as behaviour associated with particular ecological and developmental circumstances rather than as something that evolved "in order to" make an animal clever.

Sea otters (Enhydra lutris) provide a frequently cited marine example. They have been observed bringing hard-shelled prey such as some mollusks to the surface and using a rock — sometimes balanced on the chest while floating, sometimes a fixed rock or a hard surface — to break the shell open. This pounding behaviour fits common definitions of tool use because an external object is used to alter the condition of another object, here the prey item.

The behaviour is well described, but it is not identical across all individuals or populations, and the degree to which it is shaped by learning versus other factors is the kind of question researchers treat carefully rather than settling with a slogan. Individual otters can show consistent preferences in how they handle prey, and patterns can vary by region and by the food available, which is one reason broad statements about "all sea otters" are avoided.

The sea otter case is a useful reminder that tool use is best understood within a species' ecology. The behaviour is associated with feeding on hard-shelled prey in a marine setting, and it makes sense in that context; describing it as serving a function in that niche is more accurate than implying the otters set out to invent a technique.

Several recurring cautions run through the credible literature on animal tool use, and they are worth stating plainly. Tool use does not equal a general measure of intelligence, and it cannot be ranked into a single ladder; cognition is context-specific, and an animal that excels at one problem may not at another. Using a tool also does not, by itself, tell us what an animal feels or consciously intends — observable behaviour and inferred internal states are different things, and the research keeps them apart.

Distribution and learning deserve care too. Tool use appears in scattered, distantly related groups — some primates, some birds, some other animals — which means it is not a single trait with one explanation. Within a species, behaviour can vary between populations and between captivity and the wild, so findings should be attributed to the studied animals rather than projected onto a whole class or order. Many tool behaviours appear to involve both predisposition and learning, and the old habit of forcing such behaviour into a clean instinct-versus-learning split tends to mislead.

Finally, sourcing matters. Robust claims in this area come from sustained field studies and peer-reviewed experiments documented through institution-backed references, not from viral videos or single anecdotes. FaunaHub treats the cases above as illustrative examples of a documented phenomenon, described cautiously and routed through its research-sources methodology — not as a definitive or complete account, and not as a measure of which animal is "smartest."

How the claims on this topic are studied and read:

• Tool-use definitionsWhat counts as tool use, the contested boundary cases, and why ‘technology’ is the wrong frame.

How whole groups of animals show this behavior:

• Primate behavior
• Corvid intelligence

This guide is part of FaunaHub's animal intelligence & behavior cluster. For how these claims are sourced, see animal research sources, and for the biology behind behavior, see animal senses & adaptations.