A recent paper from Mammalian Biology (behind a paywall) details the first occurrence of tool-using in pigs (click on screenshot to see a bit of the paper).
These aren’t domestic pigs, mind you, but the Visayan warty pig, Sus cebifrons, a critically endangered species endemic to three islands in the Philippines. Here’s the bristly beast under consideration (picture from Wikipedia):
Now the animals weren’t observed in the wild: they were part of a group of four pigs in the Ménagerie of the Jardin des Plantes in Paris.
A bit of the abstract:
Here, we report the first structured observations of umprompted instrumental object manipulation in a pig, the Visayan warty pig Sus cebifrons, which we argue qualifies as tool use. Three individuals were observed using bark or sticks to dig with. Two individuals, adult females, used the sticks or bark, using a rowing motion, during the final stage of nest building. The third individual, an adult male, attempted to use a stick to dig with. Stick and branch manipulation was observed in other contexts, but not for digging. Our observations suggest the hypothesis that the observed use of stick to dig with could have been socially learned through vertical transmission (mother-daughter) as well as horizontal transmission (female-male).
The pigs used the bark to dig depressions in the dirt, or nest pits, which they then line with leaves as a sleeping site.
A blurb about the work in National Geographic is here, and below is a video of the pigs using pieces of bark to scoop out loose dirt.
As you see, they’re not that good at it, but it does qualify as tool use? According to the National Geographic piece, it does:
The team noticed the animals—particularly the mama pig, Priscilla—would always use tools in the middle of the nest-building process. According to Root-Bernstein, this consistency in sequence, combined with the fact the pigs’ tools could physically move the soil, meets the scientific definition for tool use: “The exertion of control over a freely manipulable external object (the tool) with the goal of (1) altering the physical properties of another object, substance, surface or medium … via a dynamic mechanical interaction, or (2) mediating the flow of information.”
The researchers also added kitchen spatulas to the enclosure, thinking that those would make even better tools, but the pigs spurned those (could it be because they don’t know what they are?). Or maybe they were waiting for the keepers to produce a stove, a pan, and pancake batter (pigs are savvy).
Two questions come to mind:
1.) Do they do this in the wild? We don’t know, as only four zoo-kept pigs were observed, three of which used the tools. The observations still speaks to pig intelligence—we already knew that pigs were smart—but it wouldn’t count as tool use in wild animals.
2.) Why do they use bark instead of their snouts? If you’ve seen a domestic pig dig with its snout, rooting about for food and the like, you’ll know how efficient snout-digging is. The videos above aren’t that impressive, and bark looks like a less efficient way to dig than getting in there with your nose.
So why do the pigs use bark? Well, maybe they don’t in nature, but if they do, perhaps it’s because the soil is harder to dig, or they don’t want to injure their delicate snouts—or both. Or maybe they’re just mucking about for fun. That would still count as tool use in the wild if they did indeed excavate depressions with bark and then used the pits to rest in.
Not surprising they shunned spatulas, as that would remind them too much of frying bacon.
I’m not fully convinced that the video shows tool use. In the first bit, it seems that the pig is more trying to break the bark (to see if there is food inside?) rather than dig with it. The second bit is more convincing, but not fully so.
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Could they have observed humans using tools to do the same things? Also, if they start using tools in the middle of their nest-building behavior, do they end with tools or go back to snouts (are the tools used for finishing rather than starting)? Just wondering.
Watch out! Pretty soon they’ll see Priscilla putting on her own lipstick.
The video is disappointing! I hope there’s a long, unedited video showing the whole nest building process: digging the depression, bringing in nesting materials & arranging it & settling down for the night. I want to see the wise matriarch sow wielding the tool as part of the above & offspring imitating the adult’s actions.
I am suspicious that the video, as shown, is of short segments – why didn’t Meredith Root-Bernstein & friends hold off publication until they could video record a complete sequence & with something better than the potato she’s using? TBH I find it suspicious that all she presents is a 52 second compilation. For this to qualify as tool use I think we have to see the end result of the activity – do we get a happy pig lounging on a straw nest? If we don’t, then the activity is open to too wide an interpretation. And was there, say, 50 hours of uninteresting video we are not seeing including where the pigs mess about with bark in a non-tool use manner?
I think more evidence would be required, but what is shown is pretty suggestive of something going on. They seem to know how to get the stick deep and fling large sprays of dirt out of the depression.
They don’t seem to have bedding material [as Lou says] which is cruel on pigs
Sure. It starts with bark. Next thing you know, the pigs are wearing clothes, sleeping in beds, walking on two legs, drinking booze, and sneaking into the barn to change the Seven Commandments of Animalism to just two.
Some animals are more equal than others.
Something interesting occurred to me when reading this stuff. Why isn’t *nestbuilding* not considered tool use?
Er, too many negatives:
Why isn’t nestbuilding considered tool use?
Because they are assembling objects into a nest; they are not using an object to move or affect other objects.
Yes but is that just an interesting distinction that we humans make? Why is a bird’s nest not considered to be a tool for incubating their young? Isn’t a spider’s web a tool for catching flies?
What makes a pig using a piece of bark as a shovel more interesting than a spider building a web? Is it the fact that it is learned behaviour? Is it that there is a level of indirection i.e. that the pig is using one thing to make another thing that they use? Can I construct a post made entirely of questions? No.
I think that Aristotle’s point about how some animals have a representation of the final result in mind has some merit. (He thinks only humans have this, which is implausible to me.)
According to Wiki anyway, nest-building by hominid apes is learned by infants watching the mother and others in the group, and is considered tool use rather than animal architecture. I haven’t time to check the accuracy of that Wiki statement re definition of primate tool use.
SOURCE
I’m getting scared now from this and the Reply All podcast I just listened to about feral hogs in Texas and Arkansas (6 million of them rapidly multiplying).
https://www.listennotes.com/podcasts/reply-all/149-30-50-feral-hogs-yhUgPcHxGfb/
“Tool use” works for me.
Maybe the few sticks in the zoo are not ideal, and a pig in nature with a much wider tool palette could do better.
About a year ago in our backyard, in Welland, Ontario my wife and I watched a rabbit use a stick in its mouth to comb hair out of its back to use for nest building. She had already pulled hair out with her mouth from reachable spots but could not reach the very back part of her dorsal side without the stick.
She successfully raised 4 or five babies.
Unfortunately as soon as I grabbed my phone to video it, she dropped the stick and hopped into the neighbours yard.
I don’t know if tool use like this has been observed in wild (backyard) rabbits before.
Has anyone seen this?
That’s an interesting bunny – pity no cam.
Unrelated: The only ‘Rabbit Stick’ I know of is the amazing native American throwing stick, for hunting small game – kind of a non-returning boomerang.