Reconnect With Nature Blog

Sophisticated Tool Use In Brazilian Monkeys

Note from Con Slobodchikoff: This is a guest post by Randall Johnson, who has contributed a numer of posts to this blog and to the Dog Behavior Blog.

In a forest reserve in the savannah-like "Cerrado" biome of Central Brazil, an amazing display of planning, learning, and sophisticated tool use has been documented in a species of New World monkeys. Wild capuchin monkeys (Cebus libidinosus)— a species familiar to many as organ grinders—move along the ground, methodically tapping palm nuts that are produced at ground level to see if they are ripe. Those that pass the test are carried up into trees, where their outer cases are removed and the exposed nuts are dropped on the ground for two or three days to dry.

Then, the aged palm nuts are collected and carried to a separate nut-cracking area. There, the monkeys climb up on top of flat rocks or boulders and, using large stones they have previously selected, they start pounding the hard-shelled nuts, with the stones being used as a hammer and the boulder as an anvil.  After a few whacks, the shells are broken and the monkeys extract the kernels.

The entire process involves several days of testing, harvesting, transporting, and hammering and appears to be a planned activity—a part of the monkeys' culture—that takes place year-round.

This discovery, first reported in The American Journal of Primatology (December 2004) by a multinational research team led by Dorothy Fragaszy, a psychologist with the University of Georgia, is remarkable in that, up to that time, routine tool use in wild primates had been routinely ascribed only to chimpanzees and orangutans and, although there had been anecdotal reports of tool-using capuchins dating back to the sixteenth century, this was the first time such behavior had been scientifically documented.

Furthermore, although the stone hammers had not been fashioned in any way, their use to open encapsulated nuts is recognized as being a complex form of tool use. A number of factors (i.e., material, resistance, friability, shape, and weight) affect an object's suitability to open a hard-shelled nut, with weight being one of the most important. The heavier the object, the fewer strikes are required to crack open a nut.

Fragaszy and her colleagues originally estimated that the stone hammers weighed 16 ounces, but in a subsequent trip, they were found to weigh over two pounds. Given that adult capuchins weigh between 6-8 pounds, they were selecting—and lifting—stones a third and sometime half their own body weight.

The effective use of hammer and anvil is seen only in adults. Although juvenile capuchins are interested in the activity and often play with the procedure, they are not effective at it. It takes years of practice—and maturation—to become effective at cracking open palm nuts with the properly chosen stone.

If you would like to see a video of this extraordinary behavior, go to: http://www.youtube.com/watch?v=-G60UCeXFp0&feature=player_embedded. It's an excerpt from a BBC documentary entitled "Clever Monkey", narrated by Sir David Attenborough. In his closing remark, note his reference to these monkeys as being another intelligent species on Earth.

And if you would like to meet other animals that are known to use tools in the wild, go to: http://www.mnn.com/earth-matters/wilderness-resources/photos/15-remarkable-animals-that-use-tools/handymen

Desert Ants That Count

Note from Con Slobodchikoff: This is a post by guest author Randall Johnson, who has contributed a number of posts to this blog and to the Dog Behavior Blog.

Given that RWNB ended 2009 with a post about ants, it seemed fitting to start the New Year with another post featuring these fascinating insects.

A study done by German scientists, led by Harald Wolf, professor of neurobiology at the University of Ulm, suggests that desert-dwelling ants may have "pedometer-like" cells in their brains that enable them to count their steps and that they use this unique navigational skill to find their way back to the nest after foraging for food.

But why desert ants? Because most ants live in places that allow them to lay a scent trail on the ground that show other ants how to get to food and back home.  Scent trails, however, don't work in the desert; the constantly shifting sand scatters smells almost immediately.

So how do these ants find their way back to their nest with such unerring accuracy? It's already known that ants can use the position of the sun and the pattern of polarized light as a kind of 'celestial compass', but that doesn't explain how they determine distances with such precision.

To try to unravel this mystery, Wolf and his assistant, Matthias Whittlinger, trained two groups of Sahara desert ants to find a food site 10 meters from their nest. While the ants were busy eating, the scientists removed them and divided into three groups.

One group was left alone. The second group had pre-cut pig bristles superglued to each of their six legs, effectively giving them stilts. Ants in the third group had their lower leg segments cut off, thus making each leg shorter. (This part of the experience has since drawn some criticism. It should be noted, though, that in the wild, these segments often dry up and break off naturally without interfering with the ants' ability to walk long distances.)

The ants were then released to make their way back to the nest. The scientists watched to see what would happen. If there really was a step-counting mechanism at work, then the ants whose strides had been altered would have their calculations thrown off.

And that’s exactly what happened.  The normal ants walked right up to the nest and went inside. The stilt-leg ants, using giant steps, walked past the entrance and stopped 15 meters away. The stump-legged ants, using baby steps, stopped short of the entrance by almost 5 meters. Yet, all three groups had walked exactly the same number of steps back from the food site.

Interestingly, when the ants went out again in search of food, the two groups with altered gaits had no trouble judging the correct distance back to the nest.

Of course, this doesn't mean Sahara ants are actually counting their steps as "one, two, three, four, five," and so forth, the way we would. More likely, Wolfe explains, there is a neural mechanism at work that converts the motor excitation caused by each stride into a measure of distance.

Still, it's an ingenious solution to not being able to lay scent trails and it shows there is still much to be learned from even the humblest of creatures.

The Compassionate Ant

Note from Con Slobodchikoff: This is a post by guest author Randall Johnson, who has contributed a number of posts and comments to this blog.

I remember growing up hearing and reading about the proverbial wisdom of ants. If you check the Old Testament, Proverbs 6:6-8 tell us: “Go to the ant, O sluggard; consider her ways, and be wise. Without having any chief, officer, or ruler, she prepares her bread in summer and gathers her food in harvest.”

And let’s not forget Aesop’s fable, “The Ant and Grasshopper”, which depicted the ant as a forward-thinking planner that gathered food in preparation for the coming winter while the grasshopper danced and played his fiddle, seemingly oblivious to future. This fable was, and still is, used to teach the virtues of hard work and saving and the perils of improvidence.

In the realm of ethology, ants have long been known for their complex cooperative behavior, including simple forms of rescue behavior, i.e., sand digging, which date back to 1874. [Belt T (1874) the Naturalist in Nicaragua. London: Murray].

Now, a new study, Nowbahari E, Scohier A, Durand J-L, Hollis KL (2009) Ants, Cataglyphis cursor, Use Precisely Directed Rescue Behavior to Free Entrapped Relatives. PLoS ONE 4(8): e6573. doi:10.1371/journal.pone.0006573, shows just how sophisticated this kind of behavior is.

In a total of 54 tests, the authors experimentally mimicked a natural situation involving an ant restrained by collapsing sand and debris. Hidden underneath the sand was a nylon snare that held the ant in place. If the captive ant was from a different colony or of a different species, the rescue ants ignored it. However, if the captive was a nestmate, the rescuers responded by excavating the sand, exposing the nylon thread, carrying sand away from the snare, and then biting at the snare itself.

These experiments demonstrated that the rescuers were somehow able to recognize what has holding their nestmate in place and direct approach behavior toward that specific object. This shows that rescue behavior is “far more exact, sophisticated, and complexly organized than previously observed,” unlike simpler actions such as digging and limb pulling, which could be triggered by a chemical distress signal.

The tests further showed that rescue behavior is directed exclusively toward a nestmate and it depends on an actively produced eliciting stimulus, most likely a pheromone that contains a component that is unique to each colony. However, pheromones alone don’t explain how the rescuers were able to find the precise location of the nylon thread and target their bites to the thread itself.

The authors distinguish rescue behavior from other types of cooperative acts in that the rescuing ants risk being trapped under the falling sand and there is no reward for the rescuers other than the benefits of kinship relationship.

Obviously, the ‘wise’ ant holds onto more secrets and surprises that might inspire new proverbs and fables.

Note: The PLoS ONE article includes two videos of these experiments.

Lessons from a Turkey

This is a post from Guest Author Randall Johnson, who has contributed a number of guest posts and comments to this blog.

A few weeks ago, I came across a news item that got me thinking about the extremes our current level of separation from the natural world can sometimes carry us.

It seems a small town in Massachusetts acquired an unofficial mascot a few months ago in the form of a wild turkey, which the townspeople named ‘Freddy’. He strutted around town freely, visiting local businesses, going in and out of stores, and getting hand-outs along the way. He became something of a local celebrity, having attracting local media attention through his ‘friendly’ behavior.

However, in early August, the local police found it necessary to apprehend and euthanize Freddy after he was declared a public safety hazard for having attacked motorcyclists and passersby. Afterwards, the town held a memorial service for its beloved bird, with mourners leaving flowers and notes. One resident even set up a Facebook page in Freddy’s honor with over 1,500 friends and counting.

What the townspeople may not have known is wild turkeys can be aggressive when they lose their fear of people and, after several months of urban living, Freddy had become pretty much fearless. As such, he wasn’t an ideal candidate for relocation, as was pointed out by local wildlife officials.

Now, there was nothing unusual or out-of-the-ordinary about Freddy’s behavior, considering he’d become habituated to humans and vehicular traffic. However, the fact that some of the town’s citizens organized and participated in a memorial service for him gave me pause for reflection. It struck me that the energy and emotion that went into this act of mourning was disproportionate to the situation.

Granted, wild turkeys are the official game bird of Massachusetts.

Granted, by 1851, they had been wiped out from the state as a result of hunting.

However, in 1972-1973, the state Division of Fisheries and Wildlife launched a successful reintroduction program, starting with 37 turkeys. Today, the turkey population in Massachusetts is somewhere between 20,000-25,000!

So, they’re not threatened with imminent extinction, unlike the 16,300 or so plant and animal species that appear on the World Conservation Union’s 2007 Red List of Threatened Species.

Let’s put this into perspective even more.

Wild turkeys grow to be 4 feet tall and weigh around 20 pounds. Not exactly lightweights! Following their reintroduction, they surprised everyone—including wildlife officials—by being adaptable to residential, even urban, living, with thriving populations in Boston and Cambridge. They are opportunistic feeders, eating everything from bird seed to gutter trash, and then depositing large amounts of ‘scat’ all over the place.

Some residents report being happy to see a bit a nature strolling around, whereas others are wary, even afraid, of what these sometimes ornery birds might do, especially when children are around. More than a few people have even reported being terrorized by them, prompting local police to issue guidelines about what to do—and not to do—should people meet a wild turkey on the sidewalk.

It strikes me that reintroduction programs can be a double-edge sword. Yes, Massachusetts got its turkeys back after more than one hundred ‘turkey-less’ years. But now many of the state’s communities have a new public health and safety issue to deal with that the Fisheries and Wildlife biologists hadn’t counted on.

At the individual level, some people’s need for contact with nature leads to maudlin displays of sentimentality that make for good headlines but that’s about all.

There’s no question that we need to exercise a healthy dose of compassion in our treatment of other species. After all, humans are now the leading cause of extinction. But in addition to using our hearts, we also need to use our heads.

 

 

 

RECONNECTING WITH NATURE…THROUGH AESOP’S FABLES?

This is a post from Guest Author Randall Johnson, who has contributed a number of guest posts and comments to this blog.

Reconnecting with nature may take some unexpected twists and turns along the way, but who would have thought Aesop’s Fables would turn out to one of them? That’s right. The ancient Greek story-teller credited with collecting such timeless fables as “The Tortoise and the Hare” and “The Boy Who Cried Wolf”, each with a moral lesson at the end, may also have been a keen observer of bird behavior.

In “The Crow and the Pitcher”, a thirsty crow comes across a pitcher with water at the bottom, beyond the reach of its beak. After failing to push the pitcher over, the crow drops in pebbles, one by one, until the water rises to the top, allowing the bird to drink. (The moral of the story: Necessity is the mother of invention.)

Well, it turns out that this is more than just an old fable. Researchers Christopher Bird of the University of Cambridge and Nathan Emery of Queen Mary University of London have reported in the current issue of Current Biology that rooks, another corvid and a relative of the crow, are able to use stones to raise the level of water in a plastic container to reach a floating worm.

Bird and Emery experimented on four rooks by presenting them with a clear tube partly filled with water and a worm floating on top, and a nearby pile of stones of varying sizes. The birds spontaneously dropped stones into the water and seemed to estimate how many stones would be needed. They also quickly learned bigger stones worked better than smaller ones.

Although some species of crows have been proven to use tools in the wild, rooks do not. They don’t have to as they have easy access to food, like carrion. But in an experimental situation like this one, they easily figured out how to use the stones to reach the worm.

Says Mr. Bird, “It was a remarkable combination of some understanding of the task with really rapid learning.”  In the summary of their published paper, Bird and Emery state, “This behavior demonstrates a flexible ability to use tools, a finding with implications for the evolution of tool use and cognition in animals.”

The more we take time to watch animals, the better we see how much we share in common with them, including brain power, and how this common thread firmly and solidly connects us to the natural world that supports us all.

Now, I seem to recall Aesop also told a story about the goose that laid golden eggs. Well, if such a fabled fowl should also exist and find its way to my door, that’s one story you won’t read about in Current Biology. I’ll keep that one all to myself.

Wild Hearts, Free Spirits

Note from Con Slobodchikoff: This is a post by guest author Randall Johnson, who has been a frequent commentator on this blog, as well as a frequent guest author and commentator on the Dog Behavior Blog.

Finding a way to reconnect with nature can take place on a grand scale by walking through a tropical rainforest and feeling, rather than seeing, the immense variety of life it supports, swimming with free-ranging dolphins, or, say, coming face-to-face with a great whale. However, more often than not, it’s the everyday, seemingly mundane, events happening around us that have the power to call us back from our artificial steel-and-concrete world and ‘ground’ us, as it were, in the natural world.

A few years back, my wife and I bought a weekend / vacation home in her hometown, Lagoa da Prata, a small town in the Brazilian state of Minas Gerais.  At the time, we were living in Belo Horizonte, the state capital, working as teachers and translators and coping with the all the stress that goes along with big city life.

The house was part of a new development on a large tract of land that used to be part of the town’s biggest dairy farm and the setting clearly reflected its past: a long stretch of dirt road ran in front of the house led to the colonial-style farm house and then into a patch of dense forest. On one side of the road, there was a wide expanse of open meadow and on the other side, behind the house, a huge fenced-in cow pasture.

 Shortly after buying the house, we were ‘adopted’ by a scrawny little street dog with short dull gray fur that my wife decided to call Suzie. Following a couple of days of eating kibble and drinking fresh water, Suzie  underwent an amazing transformation:  her gray fur was replaced by a glossy, uniformly black coat.  (She was later identified by a friend of mine as a miniature pinscher, although with a non-standard color pattern.)

We soon discovered Suzie had a friend—a short scruffy male who looked a bit like Toto from The Wizard of Oz , except his fur was dirty-white. After trying several names, including Toto, we settled on Toby.  Unlike Suzie, though, Toby showed no interest in being adopted.  He hung out with us while we were at the house and we gave him food and water.  Sometimes, he took an afternoon nap inside the house, but he rarely slept there at night.

Anyway, my wife and I got into the routine of taking a walk down the dirt road early in the morning and again in the evening, right before sunset. Suzie and Toby invariably accompanied us.  

As we strolled along, I watched Suzie and Toby as they ran through meadow, Suzie leaping through the tall grass like a gazelle. Toby was less graceful, but he kept up as they chased after butterflies and small birds. Sometimes it looked as they were running for the sheer joy of it.  Once in while, they teamed up to harass the cows on the other side of the road, yapping and lunging at them, and then they’d take off again. It looked like a pleasant diversion (from their perspective, not from the cows’), maybe even a kind of adrenalin rush, because if a bull happened to be nearby, he wouldn’t hesitate to charge after them.

These were moments of boundless exhilaration. They were being themselves, having fun, unfettered by other worries or concerns, enjoying the “here and now”, which is something we 21^st century humans often have trouble doing, even in small, rural towns. They were wild hearts and free spirits, very much part of the world we share together, but more viscerally attuned to it.  

Walking down that country road was one way of seeking a reconnection with nature, but the active ingredient, the ‘bridge’ that made the connection real, was watching Suzie and Toby’s innocent, high-spirited capers as they gave me a glimpse of a purer, more primal connection that I myself cannot feel with the same intensity. Still, occasional glimpses have been enough to keep me grounded, and by reminding us that we are, first and foremost, products of the natural world, our companion animals may yet have another useful service to offer us.

--Randall Johnson

 

As Below, So Above

For several days now, as I have been taking my dog for a walk around a pond at the local state park, I have been assaulted by a deer fly (family Tabanidae). The fly always starts buzzing me in the same 30 meter (100 feet) stretch of path, where the acacia trees provide some shade and the winds blow gentle puffs of air.

The fly seems to have a very circumscribed territory. Once I get out of that 30 meter stretch, he breaks off his attack and disappears, only to reappear during my next circuit on that path.

I try to put myself into the world of this fly. I am guessing that his world is encompassed in a plot of land that has a diameter of 30 meters. This is all that he knows. This is all that he sees. At random unpredictable times, potential meals move into range, triggering a hunger response. Outside that range, potential meals vanish, as if they never existed.

With my superior vision, I can see the whole pond, and I can think that it is very quaint that the fly cannot realize that simply going outside his 30 meters would give him more potential meals. He is limited by his perception, in ways that I am not.

But then I think, how much are we humans limited by our perception? Many years ago, I met a farmer who had not traveled more than 20 kilometers (12 miles) from where he had been born 70 years previously. Now many of us travel around the globe fairly effortlessly, and we can use electronic means of perception to see what is happening anywhere in the world.

But our solar system is huge, our galaxy is larger, and our universe is larger still. We can’t see anything of what is happening there, with a few paltry exceptions of Hubbell telescopes and rockets sent to other planets.

Like the fly, our world is circumscribed. We can see much more than the fly, but in the larger scheme of things, our perception does not extend out much more than his, in terms of cosmic distance.

To paraphrase a Hermetic saying, “As below, so above.”  We and the fly have much in common. We both can only see a very small portion of reality. And as we delve into quantum physics, we are not very sure what really is reality. Perhaps there are intelligences greater than ours who think that it is very quaint that we cannot realize that by simply going beyond the limits of our current perception we can see a greater reality. Or perhaps not.

I don’t know if the fly worries about such questions. Current scientific thought would suggest that he is not capable of such thoughts.  And perhaps we too are not capable of thoughts that would transcend our reality, allowing us to see a larger world.

So what to do? In my case, I am simply going to enjoy my moment in Nature, and even though the fly wants to suck my blood, I am going to enjoy his buzzing, even as I wait for my steps to take me out of his range.

A Wasp Tale

At the beginning of summer, my wife opened up our outdoor grill, only to find that paper wasps (Polistes arizonensis) had built a nest hanging from the upper grill shelf. The nest formed a disk that was about 5 cm (about 2 inches) in diameter. She quickly closed the grill cover and came to ask me to do something about the wasps.

We did not want to kill them, so I thought that if I left the grill cover open, the heat of our summer days would drive the wasps to abandon the nest.  I opened the grill cover in the early morning, when the temperature was still cool and the wasps were not active. Since the temperature really soars during the heat of the day, I thought it would take the wasps only a few days to leave their nest.

Every day I watched them through our kitchen window to see what they would do. Rather than abandoning the nest, the wasps took their exposure to the sun in stride. During the heat of the day, they would all cluster on the underside of the nest, in the shade. As the sun started going down and the temperature started cooling off, they would crawl up to the topside of the nest and absorb some heat for the coming cooler night.

For the next month, I watched the wasps building up and maintaining their nest. The diameter of the nest is now about 13 cm (about 7 inches), and the wasps show no inclination to slow down their activity.

But now the Arizona monsoon is gathering. This is a time of violent rainstorms and thunderstorms. Each morning during the monsoon the day dawns clear and sunny, but by noon the clouds gather and the rain starts, lasting in fitful bursts of moisture through the early evening hours, and sometimes throughout the night.

I know that the rains are coming, and when they arrive, the paper construction of the wasp nest will be destroyed. Yet the wasps continue unfazed by the coming prospect of losing their nest.

I can say that the wasps are operating on sheer instinct and have no prior knowledge of the coming debacle that will engulf their home.   But then I think of how we humans do exactly the same thing, even though we supposedly are aware of the consequences. I remember watching villagers build houses of out lava on the slopes of a still-rumbling and smoking volcano in Guatemala. And I lived in San Francisco, where everyone knows that a big earthquake is going to arrive someday, but everyone hopes that it won’t be during their time.

We humans live in perilous places and we hope for the best. Perhaps the wasps are also hoping for the best. (I’m sure that some dogmatic scientists will say that wasps are not capable of hope, to which my reply is, how exactly do you know this, other than through your unverified opinion?).

But it does show that we humans and the wasps have something in common: We all are reluctant to leave behind the place that we call home.

A Tribute To Washoe And Alex

They were pioneers, and they died within a few weeks of each other. Like all pioneers, they pointed the way to new discoveries and new ways of thinking. And like all pioneers, they bore the brunt of skepticism from the naysayers, the folks who do not want our vision of the world to change.

They did not ask to be pioneers. That job was thrust on them by others. But during their lives, they showed the world a different view, a different perspective, a different reality from the comfortable one that has lasted for thousands of years.

They were Washoe the chimpanzee and Alex the parrot.

Washoe showed that a chimpanzee can learn a number of signs in American Sign Language and use those signs to communicate with people.  Not only that, but she showed that she could teach these signs to other chimps, and could communicate with other chimps, using the signs.

Alex showed that he could tell the differences between shapes and colors, and could use perfectly-enunciated words to communicate these differences to the people around him.

Washoe and Alex were both taught by careful scientists who went to great lengths to remove subjectivity from their analyses. But neither Washoe nor Alex was merely a “lab subject,” taken out just for experiments but otherwise ignored. The people around them cared deeply about their welfare.

As pioneers, both Washoe and Alex showed that animals have the cognitive capacity to use language in meaningful ways.  Because the scientists were very careful with their studies, it is difficult for the skeptics and naysayers to discount the results, although it appears to be the nature of skeptics and naysayers to keep trying.

And as pioneers, Washoe and Alex pointed the way to a different world. A world where we humans acknowledge that animals could have sentience and cognitive capacities that could include language. A world where we see animals as intelligent beings, rather than as objects that exist merely for our convenience. A world where animals are no longer considered as things to be used, but fellow creatures to be respected.

Do Ants Think?

Sometimes the days are gorgeous, balmy and calm with the sky a cloudless soft baby-blue. On such days, I am often stuck in a dark windowless auditorium, lecturing to about 100 university students in my animal behavior class. The pull of the day affects us all. I am somewhat less enthusiastic in talking about the computer-generated slides that I am showing, and the class is restless, anxious to get outside to enjoy what is left of the day.

At such times, I switch into discussion mode. I start asking the class questions that can stimulate a conversation and bring out some opinions. The students usually perk up, particularly if the subject is one that really interests them.

One of my favorite topics is the question: do animals think? I start off by asking, how many people believe that humans think? Usually all the hands go up, except for a few contrarians who are not convinced that anyone is capable of thought.

Then I ask, how many people believe that their dog thinks? About half the hands go up. How about cats? Interestingly, perhaps a third of the hands go up. Somehow, dogs seem to have more followers than cats in the thinking category.

Next I ask: how many believe that an ant can think? Almost no hands go up. Virtually everyone seems convinced that ants cannot have any thoughts.

And finally, I ask: how do you know? This generates a lot of discussion that usually revolves around the difficulty of proving that anyone, human or animal, can think. The argument usually follows along these lines: I know that I can think, so by extension, I am willing to concede that perhaps other humans can think. Can I prove it? No, not really. I can provide a battery of problems to solve that seem to require thought, but I cannot conclusively rule out a stimulus-response explanation that would not require thinking. But, because I am human, I am willing to give the benefit of the doubt to my fellow humans.

So why are many people not willing to give the benefit of the doubt to their fellow animals? The students in my class who have dogs usually tell stories of their dogs doing things that seem to require thought. Can they prove that their dogs think? No, not really. But they can identify with the world that dogs live in and the problems that dogs face, and are willing to give them the benefit of the doubt.

But almost no one is willing to give the benefit of the doubt to ants. My students cannot imagine the world of an ant or the problems that ants might face, and are willing to accept that ants do not think. Can they prove it? No, not really.

And here is the key. We are willing to accept that people think, without much proof. We are unwilling to accept that other animals think, also without much proof. Where we can put ourselves into the mind of another animal, we are much more willing to accept that the animal thinks. Otherwise, we assume that there is no thought.

The assumption that animals do not think can be dressed up with all kinds of alleged scientific evidence: The brain is too small, there is no cerebral cortex, the cortex is too small, there are no frontal lobes, and so on.

But the bottom line is, how do we know that an ant does not think? The answer is, we don’t. Unless we are willing to argue from definition. We can define thinking as only a human property, and then we can sit back in great satisfaction that we have solved the problem of animal thinking once and for all.