Tetrapod Zoology

Chimpanzees make and use spears

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By now you’ve probably heard the news: chimpanzees have been reported manufacturing, and using, spears (Gibbons 2007, Pruetz & Bertolani 2007). I’ll say that again. Chimps Pan troglodytes make and use spears….

Specifically, the chimps concerned are of the subspecies P. t. verus, a taxon that some researchers (Morin et al. 1994, 1995) have tentatively elevated to specific status. As reported in Current Biology by Jill Pruetz of Iowa State University and Paco Bertolani of the University of Cambridge, the observations concern the 35 chimps of the Fongoli site in Senegal. On more than 20 occasions between March 2005 and July 2006 the Fongoli chimps were observed to fashion wooden spears and then use them in hunting concealed bushbaby prey that were hiding in cavities in trees and branches. Unlike many of the tool-using chimps we are familiar with, such as the Gombe and Tai National Park chimps, the Fongoli chimps are not rainforest animals, but inhabit a grassland-woodland mosaic.

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Tool use in chimps has been known about for several decades, and over the years the sorts of tools that chimps have been observed using have become increasingly sophisticated. Termite fishing was reported by Jane Goodall in the 1960s and the use of hammers and anvils to break open nuts became well known in the 1990s (Goodall 1968, Boesch et al. 1994). The adjacent image shows one of the Gombe chimps using a tool to catch termites: those who’ve read any of Goodall’s research will know the significance of the chimpanzee individual shown in the photo [image from here]. While there is one account in which a Tanzanian chimp was reported to use a tool to rouse a squirrel that was then killed and eaten (Huffman & Kalunde 1993), the manufacture and use of spears* is something very, very new. The chimps would break off a live branch, remove its twigs and leaves, and then form a sharpened point with their incisor teeth. The resultant tools averaged 60 cm in length.

* Some primatologists have already noted that use of the term ‘spear’ implies that the objects are thrown at prey, whereas the tools used by the Fongoli chimps are apparently used as stabbing weapons. There may, then, be some dispute over terminology.

The tools were deployed, not simply as probing devices as is the case when the chimps fish for termites, but as stabbing weapons that were thrust forcefully into the cavities. The spears were not used to extract the prey: from the description that Pruetz & Bertolani (2007) provide it seems that the bushbabies were killed within the cavity by the spear tip, and then extracted by hand. Only one successful kill was observed, and even in that case it could not be determined with certainty whether the spear was responsible for the death of the bushbaby. However, the evidence still looks pretty good.

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The fact that chimps manufacture spears raises the possibility that such tools appeared much earlier within hominid history than we’ve thought until now. This ties in with recent work on archaeological sites, showing that chimps in what is now the Tai National Park have been using stone tools for thousands of years: a discovery which supports antiquity of tool use within hominids [adjacent image shows exacavated chimpanzee stone hammer, from here]. Pruetz & Bertolani (2007) draw attention to the fact that the Fongoli chimps are savannah-woodland inhabitants, apparently frequenting environments similar to those favoured by australopithecines and other close relatives of modern humans. It seems increasingly likely that the diversity of tools manufactured and used by australopithecines and other fossil hominids was higher than we can demonstrate from the fossil record, and the fact that female and immature chimps seem to be the primary makers and users of these tools suggests, significantly, that these are the animals that play the most important role in the early development of some tools.

This is pretty amazing stuff, and time constraints prevent me from writing more about it. National Geographic features the story here, and includes video clips of the chimps using their spears. The image at the top of the article is borrowed from National Geographic.

Coming next: proto-narwhals and beluwhals, and rhinogradentians (kidding).

Refs – -

Boesch, C., Marchesi, P., Marchesi, N., Fruth, B. & Joulian, F. 1994. Is nut cracking in wild chimpanzees a cultural behavior? Journal of Human Evolution 26, 325-338.

Gibbons, A. 2007. Spear-wielding chimps seen hunting bush babies. Science 315, 1063.

Goodall, J. 1968. The behaviour of free-living chimpanzees of the Gombe Stream Reserve. Animal Behaviour Monographs 1, 161-311.

Huffman, M. A. & Kalunde, S. M. 1993. Tool-assisted predation on a squirrel by a female chimpanzee in the Mahale Mountains, Tanzania. Primates 34, 93-98.

Morin, P. A., Moore, J. J., Chakraboty, R., Jin, L., Goodall, J. & Woodruff, D. S. 1994. Kin selection, social structure, and the evolution of chimpanzees. Science 265, 1193-1201.

- ., Moore, J. J. & Woodruff, D. S. 1995. Chimpanzee kinship: response. Science 268, 186-188.

Pruetz, J. D. & Bertolani, P. 2007. Savanna chimpanzees, Pan troglodytes verus, hunt with tools. Current Biology doi:10.1016/j.cub.2006.12.042

Comments

  1. #1 JW Tan
    February 22, 2007

    Darren, I hope you were kidding about the kidding about rhinogradentians. I have to confess I was completely taken in (in the end Google disabused me of my illusions), but nevertheless would like to see something about the creatures in a *ahem* speculative zoology post…

  2. #2 Mike
    February 22, 2007

    “Some primatologists have already noted that use of the term ‘spear’ implies that the objects are thrown at prey, whereas the tools used by the Fongoli chimps are apparently used as stabbing weapons. There may, then, be some dispute over terminology.”

    When talking about military weapons, you’d use “javelin” to be clear you’re talking about throwing the thing and “pike” or “lance” to be clear you’re talking about thrusting with it. Spear is ambiguous enough that the terms “thrusting spear” and “throwing spear” aren’t uncommon, so they should go with “spear” and avoid embarrassment when some chimp is seen throwing one.

  3. #3 wolfwalker
    February 22, 2007

    Darren, this bit from your post leaped out at me:

    over the years the sorts of tools that chimps have been observed using have become increasingly sophisticated.

    Is it possible that this is simply because we happen to be observing at the time that chimps are learning to make and use these tools, by watching humans who already know how to make and use them? That there’s little or no real creativity involved, just imitation?

  4. #4 Darren Naish
    February 22, 2007

    This has indeed been suggested (viz, that chimps might be making new tools by copying humans). It is mostly – though not entirely – negated by the discovery of archaeological sites showing that the chimps have been making their tools for at least 4000 years independently of humans. John Hawks discussed this subject here. The fact that we have only recently started to observe and document these tool-making skills is probably more to do with the history of our observational science, not of the chimp cultures.

  5. #5 Mick
    February 22, 2007

    Wolfwalker and Darren:
    What circumstances have occured in recent history wherin the chimps would be exposed to spear-making humans when they had not been previously?
    Please don’t say violent video games.

  6. #6 R. Arthur Wilderson
    February 23, 2007

    * Some primatologists have already noted that use of the term ‘spear’ implies that the objects are thrown at prey, whereas the tools used by the Fongoli chimps are apparently used as stabbing weapons. There may, then, be some dispute over terminology.

    Good heavens no! Didn’t they learn their proper polearms names?

    A spear is a generic term for a pointy stick, while a javelin is a specifically thrown weapon. A lance is by modern usage a thrusting spear used from horseback and a pike is one used on foot, especially in anti cavalry formation. I shall assume that the last two definitions are not particularly relevant to chimps, but you never know what will be discovered next!

  7. #7 Nathan Myers
    February 23, 2007

    Surely there were humans for the chimps to observe 4000 years ago too. Furthermore, those humans would have been much more likely to be using tools and weapons a chimp could understand. (I mean, everybody agrees we’ve been here since at least, what, 4004 BCE?)

  8. #8 Dave Godfrey
    February 23, 2007

    The earliest found spears are 400,000 years old and also seem to have been used for throwing. (Its tapered at both ends so was almost certainly used for throwing). They seem to be made for use with a flint head, but they weren’t found. Prior to that the oldest spears were 125,000 years old, and used for stabbing.

    Maybe there’s something to do with the significantly larger brains in the species of Homo that enables us to use throwing weapons, animals with smaller brains can’t understand that the object doesn’t have to remain attached to you in order to have an effect. (Dropping bones in vultures is a notable exception.)

    Hatmut Thieme, Lower Palaeolithic hunting spears from Germany, Nature 385, 807 – 810 (27 February 1997).

  9. #9 wolfwalker
    February 23, 2007

    Mick asked: What circumstances have occured in recent history wherin the chimps would be exposed to spear-making humans when they had not been previously?

    Hmmm… I was going to suggest an answer, but now I’m not sure it’s necessary. I thought contact between humans and chimps, especially scientists and chimps, was a relatively recent phenomenon. However, the Wikipedia entry for the chimpanzee claims that humans first encountered chimps many centuries ago, and that Western explorers first observed chimps making and using tools four hundred years ago. I don’t consider Wikipedia a 100% reliable source, but the technical, non-political articles generally seem to be right more often than not.

  10. #10 David Marjanovi?
    February 23, 2007

    animals with smaller brains can’t understand that the object doesn’t have to remain attached to you in order to have an effect.

    Don’t chimps throw all manner of stuff at attacking leopards?

  11. #11 Nathan Myers
    February 23, 2007

    Maybe the objection that chimps might have picked up spear use from watching humans is spurious. Humans pick up (fill in your own example of culturally defined activity) from watching humans. Chimps pick up spear use from watching other chimps. Ultimately one does it first, inspired by some random event. What seems significant, species-wise, is not that an individual does something novel, but rather that others copy it.

  12. #12 QrazyQat
    February 23, 2007

    Humans hunt and eat chimps, and probably have been doing so for at least 100s of thousands of years.

    And this new info further cements the ideas of the “Woman the Gatherer” model regarding females and tool use. And idea, BTW, that dates back now 35 years, to Sally Linton’s paper (she was a grad student at the time, I believe) and carried through the work of Nancy Tanner and Adrienne Zihlman (who I see has been quoted re the story in some of the news pieces).

  13. #13 Mike
    February 24, 2007

    “Maybe there’s something to do with the significantly larger brains in the species of Homo that enables us to use throwing weapons”

    IIRC, chimps have been seen throwing found objects at potential threats. From there to throwing a pointy stick that you’ve previously used to stab with would seem a small step (doing it well being another thing).

    And if chimps half a million years ago picked up spear use by imitation of our ancestors how does that make them different from us? They are merely in the same boat as almost all of us: learning by seeing it done by someone else. Unless, that is, humans are instinctive spear throwers or we’ve all been independently ‘discovering’ the use of spears all these years instead of being learning by example, and I don’t think that likely.

  14. #14 QrazyQat
    February 24, 2007

    European humans first encountered chimps some centuries ago, but people in Africa have been living alongside chimps (and probably killing and eating them, as they still do) for pretty much as long as both have been around.

  15. #15 Dave Godfrey
    February 24, 2007

    IIRC, chimps have been seen throwing found objects at potential threats. From there to throwing a pointy stick that you’ve previously used to stab with would seem a small step (doing it well being another thing).

    Fair enough. The difference in the levels of tool use between humans and chimps is awkwardly large to study how more complex tool-making behaviour has evolved. I wondered if understanding “action at a distance” (for want of a better phrase) of the kind that humans (and their ancestors) can do was something that was beyond chimps, but appeared with the first members of the genus Homo.

    (A couple of extant erectus would be really handy for this kind of research.

  16. #16 Nathan Myers
    February 26, 2007

    (A couple of extant erectus would be really handy for this kind of research.)

    Surely the House of Lords can provide specimens.

  17. #17 Organic Chemistry
    April 5, 2007

    The thing to remember here is that chimps will throw anything…don’t they throw their feces too. I would also ask if this is a mimic behavior that they are exhibiting.

  18. #18 Graham King
    March 6, 2008

    I would be surprised if there were ANY physically-possible, visually-evident act which witnessing chimps would not curiously try to emulate.

    I wonder if they could learn to use catapults, slingshots and blowpipes, if shown their use… Seriously!

    I’m not suggesting it’d be a good idea to give them that opportunity though. Future researchers and locals living alongside might not thank us.

    More constructively… does anyone know if they can be taught not only to tie/untie knots, but use a hammer and nails, saw, drive screws or fit nuts to bolts?

  19. #19 David Marjanovi?
    March 7, 2008

    The thing to remember here is that chimps will throw anything…don’t they throw their feces too.

    Read the post again: they don’t throw the spears, they use them for stabbing.

    I would be surprised if there were ANY physically-possible, visually-evident act which witnessing chimps would not curiously try to emulate.

    You seem to have made a comment without reading all previous comments first. Shame on you.

  20. #20 stripey_cat
    August 4, 2010

    Graham @18 – *Horses* are (anecdotally, and in my own observation) able to learn to unfasten finger-tightened nuts, bolts (of the slidey sort), buckles, stud-billets, bras (don’t ask!), pin-hinges (lift the door off), nailed joints, zips, buttons, locks if the key is left in them (that was learned from observation, though) and many other things that look interesting, stand between them and food, or make the humans wig out. Their track record for putting stuff back together is less good (all small objects have to be manipulated with the mouth), but some learn to manage bolts, and can drop pins back through hasps or put string-loops back over the gate. If chimps aren’t more mechanically inclined than horses, and much better able to manipulate small objects, I’ll eat the hat of your choice.

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