On October 16th, 2017 we learned about

Currency made from fruit bat teeth offers an opportunity for conservation

How much is a tooth worth? It probably depends on who you ask. A tooth that needs saving at the dentist can get pretty pricey, while a baby tooth that falls out might net around a dollar from the tooth fairy. For mammals like giant fruit bats living in the Solomon Islands, a mouth full of teeth may cost them their lives. Traditional practices on various islands use bat teeth as a form of currency, primarily for ceremonial events like weddings. This, along with the large bats’ meat, has led to increased hunting which is now threatening the safety of various bat species. The good news is that the demand for bat teeth may also turn out to be a way to help keep these same species alive.

Hunting bats for protein and profit

As their name implies, giant fruit bats eat fruit and are big. The Pacific flying fox (Pteropus tonganus), for example, can have a three-foot wingspan while weighing a under two pounds. That may be smaller than your average chicken, but it’s big enough to make these bats a target for islanders looking for scarce sources of protein. It also means that the bats grow teeth large enough to trade and even drill holes in for use in jewelry. While P. tonganus aren’t technically endangered yet, they’re one of many species of bat that are hunted on the Solomon Islands without much care for population management or conservation.

Dietary needs are of course hard to ignore, but trading in teeth has certainly raised a few eyebrows throughout history. Solomon Islanders have been using teeth as currency for centuries, with the practice temporarily dropping off in the 19th century, around the arrival of Christian missionaries. The teeth haven’t only come from bats either, as dolphins have also been hunted for their teeth and meat in a similar manner to the bats. These practices saw a revival around 1948, and while younger islanders feel like these traditions are once again on the decline, they’re still significant enough to make an impact on local ecology. Since these bats are key seed dispersers for the islands, any shift in their populations can spell trouble for the plants, and other animals, that depend on them.

Using culture to motivate conservation

Conservationists focusing on fruit bats suggest that the continuing use of teeth may actually be an opportunity. The fruit bats need better protections from hunting, but also from indirect threats like habitat loss where their deaths are simply an unfortunate byproduct of other goals. However, if the bats’ teeth retain their cultural value, than the bats’ lives will too. The hope is that educating people about the bats’ vulnerability will inspire people to protect them as part of preserving their people’s traditions. Banning hunting outright might help in the short term, but it probably won’t make people feel invested in the bats’ continued success on the islands either, exposing them to further habitat degradation. Promoting teeth as tender as a way to save bat lives may seem counterintuitive, but it’s not a terribly far-fetched idea. Other animals, from sharks to pigs, may also stand a better chance at survival if humans maintain our reason to kill some (but not all) of them.

Source: How to save giant tropical fruit bats: Work with local hunters who use bat teeth as money

On October 15th, 2017 we learned about

Chimpanzees’ use of sticks to stab and scoop shows two sides of tool invention and innovation

While humans love our tools so much that we strap them to our faces, we’re certainly not the only animal to use objects to improve our lives. Crows use sticks to access food, monkeys use rocks to open nuts, and dolphins use sea sponges to find hidden prey. In many of these cases, there seems to be a cultural component to the spread of any particular technique— the sponging dolphins, for instance, only pick up those particular foraging behaviors if their mother teaches them. In chimpanzees, the transmission of tool use is less clear, as some stick use seems to be localized, while other studies have found that chimps’ may have some innate ingenuity the is the mother of their inventions.

Shared strategies for sharpened spears

An example of an apparently localized specialization can be seen in the chimpanzees of the Fongoli savanna in Senegal. Many chimps are known to wield sticks for various tasks, like fishing for termites, but this group has invented a tool that’s engineered for use as a probe and a spear. There’s a five-step process making these spears requiring cleaning the shaft of twigs and leaves, plus chewing one end to sharpen it into a point. Once finished, the weapon-wielding chimps would then use them to both find and spear bush babies hiding in trees, going as far as to check the tips of their spears for traces of blood to know if they were on target or not.

Like much tool use, these spears opened up new opportunities for chimps that didn’t or couldn’t participate in the group’s primary hunting activities. Adult male chimps hunt for meat by other means, but the specialized spears allow female and juvenile males to find their own food, a strategy that becomes more important when other food sources are seasonably scarce.

There’s a good chance that the development of these spears and their usage is the result of iteration and cultural transmission of knowledge. More and more examples of animals learning from the examples of their peers and parents are being discovered, even if it’s not strictly tied to tools. Other researchers have been curious about tool use in the other direction- how does it get started? Based on the example above, if a generation of chimps grew up without the tools and techniques invented by their parents, would they be left bewildered when presented with rocks, sticks or other would-be tools?

Scooping with sticks, from scratch

A separate study looked into just that, presenting captive chimpanzees as the Twycross Zoo with some raw materials that are regularly manipulated by some of their wild counterparts. Wild chimps are known to use sticks to collect protein-rich algae from rivers and ponds, basically like crude fondue-forks. Under the assumption that, like spearing bush babies, this method for algae-scooping had been taught by one chimp to the next, researchers gave captive chimps some nondescript sticks and buckets of water with bits of food floating in it. They wanted to see what the chimps would come up with to solve this little challenge on their own.

The captive, naive chimpanzees not only engaged with the task, they started scooping food in a very similar manner to their wild kin. The resemblance to the wild algae scooping was significant, as the captive chimps even adopted the same scooping motion to use their sticks. This all suggests that at least some of the object manipulation that chimpanzees engage in is built into their brains to a certain extent. It’s not necessarily singularly-focused instinct, but a predisposition for exploring what objects can do. Expanding this line of thinking out to other primates like humans, we know that human brains have internal reward loops for learning new things, and so this kind of foundation may be enough to get us to experiment with just about anything we can get our hands on, including sticks.

Source: Chimpanzees Learn to Use Tools On Their Own, No Teaching Required by Leah Froats, D-brief

On October 12th, 2017 we learned about

Probing the power of young pigs’ brains

Winnie the Pooh‘s Piglet, between hiding from heffalumps and worrying of woozles, never seems especially bright. Wilbur is reputed to be “some pig,” in Charlotte’s Web, although it’s clear that he’s not exactly the brains behind his rise to fame. On the other hand, Napoleon and Snowball are clever enough manipulate their peers to claim political power in Animal Farm. Looking outside fiction, farmers often consider pigs to be at least as intelligent as a smart dog, but usually in anecdotes instead of consistent signs of cognition. With all these mixed opinions, researchers have been taking steps to try to get a better sense of just how clever pigs really are.

Keeping track of new toys

Starting small, a study tested piglets’ memories and understanding of novelty by seeing how they responded to toys. It had previously been established that piglets did prefer novelty in the form of new toys over old ones, but this experiment wanted to establish what age piglet brains became capable of really judging what was new and what wasn’t. At four weeks old, piglets, especially female piglets, could consistently notice which toys were new to them, and which toys they’d seen two days earlier. Younger piglets wanted novelty too, but at three weeks could be fooled into thinking an familiar toy was new if it was simply presented to the piglet in a new location. Overall, this behavior puts these three- to four-week-old piglets on par with a three- to four-month-old human.

Kunekune pigs closely watch their kin

A study of Kunekune piglets in New Zealand was a bit more demanding of its test subjects. Instead of looking at how well piglets responded to novel stimuli, these piglets were tasked with observing their mother’s behavior, then applying it to their own experiences later on. While many animals can learn to imitate the behavior of their peers, observing then reproducing specific problem solving is a less common feat. In this case, piglets watched their mother or aunts through a partition as the older animal worked on getting food out of a puzzle box that required multiple, specific steps to open.

The piglets that watched an adult did seem to pick up a few pointers. They didn’t mirror the behavior they’d observed perfectly, usually changing the position the adopted for one of the required steps while still achieving the same overall motion. This indicates that they understood the task’s goal and what their motions would do to achieve it, rather than simply reproducing their mother’s actions by rote. Piglets in the control group that didn’t observe an adult took longer to figure the boxes out, as one might expect. However, once they’d invented their own technique, they were able to remember and reproduce their solution up to six months later.

Researchers suspect that the Kunekune pigs may be unusual amongst their porcine kin. The pigs are raised in family groups with space to roam and explore. This seems to provide a more challenging, enriching environment that stimulates social learning and problem solving in a way other pigs miss out on.

Source: Kune Kune Piglets Possess Social Learning Skills And Have An Astonishingly Good Memory, University of Veterinary Medicine, Vienna

On October 10th, 2017 we learned about

Isolating the impact of individual personalities on fish schooling performance

Anyone who’s worked on a group project has probably enjoyed the… complexities, shall we say, of trying to coordinate with people who aren’t in sync with the team. They’re not on the same page as everyone else, and don’t seem to care much either. When writing a report, this can feel very disruptive, but it looks like this kind of behavior may be helpful in some situations, like when a school of fish is hunting for food.

Sticking too close together

Researchers defined a few personality traits they thought might affect schooling behavior in stickleback fish. These included things like how closely one fish would want to sync its speed to its neighbor, or how often they would swim stray from the group. Once fish were sorted by these traits, they were allowed to explore an environment in more homogeneous groups, such as a group of fish that all prioritized social cohesion and synchronization.

It turned out that when every fish was prone to stick together, the school was unsurprisingly cohesive, but at a cost. With every fish happily doing their best to stay in the middle of the group, they barely went anywhere. Beyond that, they stuck together, but weren’t actually well coordinated in doing so, possibly because each individual was more interested in following each other than moving in a single direction. The test environment was seeded with food for the fish to discover, and schools composed of highly-cohesive fish simply weren’t as efficient at finding anything to eat. Schooling also provides protection from predators picking a single target to prey on, but checking on how safe this slow-moving school was wasn’t part of the experiment.

Simulating asymmetric schools

Building on these tests, researchers also ran simulations of schools composed of different personality types. They found that the introduction of a few fish that are less interested in sticking with their neighbors actually reshaped the whole group for the better. Even a couple of fish that were simply swimming a bit faster than a neighbor helped make the school more coordinated, probably by providing a course for slower swimmers to follow.

It’s probably too early to call the behavior of the faster, more exploratory fish leadership, since that would imply a lot of intent that this research wasn’t testing. However, it also shows how intent may not be strictly necessary, and that even minor variations in behavior can make a big difference in the school’s outcomes. This might not make your next group project easier, but it will likely inform our understanding of group dynamics as a whole, from flocking birds to the designs of swarming robots.

Source: Individuality Drives Collective Behavior Of Schooling Fish, Scienmag

On October 8th, 2017 we learned about

Sea birds’ sense of direction seems to hinge on their sense of smell

Not that we should start trusting breakfast cereal mascots all the time, but it turns out that Toucan Sam was onto something when claiming that we should “follow his nose.” It seems that while keel-billed toucans probably don’t smell much of anything with their large beaks, other birds are turning up with some considerable uses of olfactory information in their daily lives. Studying birds’ sense of smell isn’t always easy, but a recent look at Scopoli’s shearwaters suggests that these birds aren’t using their noses to find anything like Froot Loops, but instead use them to find their way back to shore when flying over the sea.

Staying oriented over the ocean

Scopoli’s shearwaters (Calonectris diomedea) resemble oversized gulls, complete with slightly hooked beaks for snatching up seafood. Their diet is largely based around grabbing squid from just under the surface of the water, but they can dive as deep as 50 feet under the water if need be. Depths aside, their foraging often covers a lot of lateral territory, with birds easily traversing over 100 miles in a single trip. A journey like that is only possible if one has confidence in their navigation, which is why researchers tracked some birds after plugging up their noses.

To test how Scolopi’s shearwaters are using smell to navigate, 32 birds were divided into three groups. The control group was left untouched, but the other two had their suspected navigation systems disrupted. In one case, that meant attaching magnets to their beak, supposedly to disrupt the birds’ sensitivity to the Earth’s magnetic field. The last group had their olfactory abilities disabled, using zinc sulfate to block smells but not airflow for breathing.

Following fragrances

The birds were electronically tracked, revealing that the zinc sulfate disrupted the birds’ sense of direction more than anything. When flying home, the aroma-blind birds still flew a straight course, but they did so along he wrong trajectory. As they continued, they never really course-corrected, making scientists suspect that they were missing the scents of odorous landmarks that they normally used as reference points. It’s suspected that these smells may originate from algae and phytoplankton under the water, but at this point we can’t be sure what the birds are smelling to make their mental maps.

Bird navigation has been the subject of a lot of research, albeit without the emphasis on odors. With many species making epic migrations, sometimes around the world, researchers have been trying to figure out what birds are using for their internal GPS systems. Despite the efforts of the Froot Loops’ marketing department, birds’ sense of smell hasn’t previously been seen as a likely navigational tool. This study suggests that, at least for some species, a lot of navigation is sensed through the nose.

Source: Experiment Shows That Birds Can Use Smell to Navigate in the Air by AFP, Seeker

On October 3rd, 2017 we learned about

Results are surprisingly mixed for raccoons tasked with retrieving rewards by raising water

At preschool, my son heard a story about a raccoon that managed to crawl into a full compost bin, then refuse to come out, even when the bin was turned upside-down. It’s an unusual scenario, but in no way a stretch for raccoons, who have reputations for exploring, investigating and manipulating all kinds of objects we’d often prefer they just leave alone. It’s also a reputation that raised expectations about how well raccoons would handle an ‘Aesop’s fable‘ test. After all, even crows, who aren’t known for sneaking through pet doors to access kitchen cupboards, managed to complete the test, although in fairness they’re supposedly the ones that led to its invention in the first place.

The fable, and the resulting test, challenges an animal to gain access to water in a narrow tube, using rocks. In 2014, New Caledonian crows (Corvus moneduloides) figured out that dropping rocks into the tube could displace enough water to raise the water level to the top of the tube. Not every individual crow got it, but those that did seemed to even understand the point of their actions. Rather than just drop things in randomly, they learned to pick bigger, solid objects that would sink, versus smaller, hollow objects that might not move as much water. Like a kindergartner or first grader, the birds must have seen cause and effect well enough to make predictions about which tools would best complete their task.

Raccoons planning or playing?

When eight raccoons (Procyon lotor) were given a similar challenge, they seemed a bit less… focused? Water wasn’t thought to be exciting enough, so the raccoons were baited with a marshmallow floating in the water, which in a way gives a clue about floating versus sinking objects. When stones were left near the tube, the raccoons didn’t see the connection, although to be fair, neither did crows on their first try. Rocks were then placed near the opening the tube, so that the raccoons might bump them and trigger an accidental demonstration of displacing water. Accidents earned four of the eight test participants a marshmallow, but only two seemed to grasp things well enough to then actively pick up rocks on their own.

The the two actively successful raccoons were then challenged again, being given choices about what objects to dunk in the water. Unlike the crows, the raccoons didn’t seem to be assessing the size or weigh of anything. They were interested in all kinds of objects, without any indication that they were trying to be efficient in their activity. Instead, researchers suspect that they were more intent on exploring. Follow-up tests may give raccoons more time to familiarize themselves with the tubes and rocks, as this explorative behavior may just be a sign that the raccoons needed more time to play with everything to learn about it before they were ready to start applying that information to specific challenges.

There was one more twist on this intelligence test, in which one raccoon basically decided to think outside the box entirely. Instead of worrying about water levels, this raccoon spent her energy on figuring out how to knock the whole tube apparatus over, spilling the water and getting the marshmallow in one bold movement. While she technically failed the Aesop fable test, she nonetheless demonstrated some solid problem-solving skills.

Source: Raccoons solve an ancient puzzle, but do they really understand it?, Phys.org

On October 2nd, 2017 we learned about

Modern frogs with a big bite predict that Beelzebufo ampinga had a monstrous mouth

Every kid knows that frogs eat bugs, overlooking the fact that many species also put fish, snakes, rodents and even other frogs on their menu as well. That list got some interesting additions lately, with a prehistoric frog species, Beelzebufo ampinga, being found capable of consuming small dinosaurs. Nobody today has had the privilege of being bitten by these ten-pound amphibians, but analysis of some of their surviving relatives suggests that the so-called “devil frogs” may have had a stronger bite than a German Shepard.

The study started with much smaller, safer mouths. South American horned frogs in the genus Ceratophrys are the current big bite kings among frogs, although they they don’t grow nearly as large as their extinct counterparts. Instead of relying on the typical, and amazing, tongue-snare techniques other frogs use to capture small prey, Ceratophrys are ambush hunters that wait to surprise and gobble up animals nearly the same size as themselves. When measured with a device called a force transducer, the a frog with a mouth under two inches could bite with around six-and-a-half pounds of force. That’s not enough to even break your pinky, but it’s not bad for such a tiny creature.

Bites from bigger mouths

From the initial measurement of a daintier Ceratophrys frog, researchers then calculated what a bigger set of the same jaws could do. Strength is dependent on muscle and bone size, so scaling up a Ceratophrys mouth quickly makes for a more impressive bite. With a four-inch mouth, a Ceratophrys bite becomes comparable to a toad-headed turtle, although your finger bones might still survive a single chomp. Taking these calculations further, B. ampinga was even larger, and thus was probably capable of biting as hard a wolf or smaller tiger. With that kind of strength, biting through bones and entire bodies would be a possibility, which is why small dinosaurs like hatchlings would have been a practical meal option for these formidable frogs.

Before you rush off to argue about B. ampinga vs. T. rex, it should be noted that these are estimates. B. ampinga has very very similar skeletal anatomy to today’s horned frogs, but it wasn’t a perfect match. The ancient devil frogs had slightly longer, shallower skulls, which may have reshaped the musculature into a less powerful configuration. Still, even with some allowances, these mouths were likely bad news for anything that could fit inside.

Source: Bite force research reveals dinosaur-eating frog, Eurekalert

On September 26th, 2017 we learned about

Densely-packed pigeon brains out-perform humans at task-switching tests

Mammals have incredible, complicated, calorie-hungry brains. Portions of gray matter specialize in everything from counting to memory to detecting what may or may not be a spider in our visual field. Even with all this specialization, our brains are also quite flexible, taking on new tasks if other cells are somehow unable to do their original job. There’s a lot to be proud of in that skull of yours, especially since it’s almost a quick as what you find in pigeons.

Simplicity vs. sophistication?

Now, pigeons and other birds don’t have all the complex structures you find in mammal cortex, but it hardly seems to slow them down. Crows, for instance, are known to lack the neocortex that mammals like humans use to count objects, but they still handle quantities better than many other animals. This was of interest to researchers, who wanted to figure out exactly how well bird brains measured up to a human’s six layers of cortical tissue.

The head-to-head test specifically looked at how well pigeons and people could multitask. In one round of tests, participants had to quickly switch from one task to another. In this case, the goal was to transition as smoothly and immediately as possible, to the point that one mental process literally took place at the same time as the other. Both humans and pigeons showed some slowdown with this challenge, since brains were juggling twice the amount of work they were comfortable with. The second round of tests was similar, but included an intentional break in the middle of the switch-over to allow brains to end one process before starting the other. Changing focus like that probably doesn’t feel too messy, but requires a bit of back-and-forth coordination between neurons to work correctly.

Neuronal density and distances

This is where the pigeon brains really shined. The period of mental coordination to fully switch over to a new task was 250 milliseconds shorter in the birds, meaning their brains were somehow handling this process faster than our more complex noggins. That may not sound like an impressive margin, but considering your brain only needs 600 milliseconds to think of and pronounce a word with proper declension, 250 milliseconds is nothing to scoff at.

Researchers suspect that the pigeons edge boils down to something as simple as proximity. Bird brains have been found to be around twice as dense as mammal brains, meaning they have twice the neurons per cubic inch of gray matter that we do. This is probably how birds are able to pull of their cognitive feats without all our brain structures, and as the pigeons demonstrated, do some of them faster. In the case of task switching, the densely-packed neurons would be closer together, and so each synaptic transmission would need to cover less distance. In aggregate, that would add up to a speedier transit time per thought, letting pigeons shift their focus faster than we can.

Source: Pigeons better at multitasking than humans, EurekAlert!

On September 25th, 2017 we learned about

Poisonous frog adaptations block harm from their toxins, as well as hearing their own voices

Anthony’s poison arrow frogs (Epipedobates anthonyi) aren’t cannibals, but they still need to defend themselves against the potentially lethal toxins found in the hundreds of poisonous frog species around the world. Toxins like epibatidine course through their bodies to scare off predators who want to avoid things like hypertension, seizures and of course, death. These neurotoxins pack a punch to just about any species, and the only way the frogs can safely carry them is thanks to some specific adaptation that let their brains continue functioning while blocking the toxins they naturally create. It seems that the real trick to being poisonous is figuring out how to survive your own defenses.

Reworking nerve receptors

Part of what makes epibatidine an effective toxin is that it attacks nervous systems in a way that’s universally applicable to most predators. Nerves are triggered in a number of ways, including proteins that fit into special receptors built into the cell membrane. Once the receptor is activated by the right protein, it triggers activity in the cell that can help produce a larger physiological event, like joining with other cells to record a memory. The epibatidine essentially hijacks this process, fitting in cell receptors to activate them, but without any natural “off” mechanism. The cellular activity then runs off the rails, causing all kinds of problems if enough cells are affected at once.

Since the frogs would like to keep the use of their nervous systems under control, they’ve evolved slightly unusual receptors in their nervous systems. This lets them continue to function like other animals, except the epibatidine doesn’t fit in the frogs’ cells to do anything. In retrospect, it’s a fairly straight-forward solution to being filled with toxins, and has evolved at least three times in frog lineages, although it’s obviously unusual enough that most creatures aren’t packing poisons to make themselves inedible.

Hitting mute on potential mates?

Ignoring one’s own poisons aren’t the only thing poisonous frogs have been found to block out. Pumpkin toadlets (Brachycephalus pitanga), a tiny orange frog from Brazil, can’t hear their own calls. They’re not deaf, but they’ve evolved to have ears that can’t detect the frequency of their own voices, leaving them able to hear their surroundings but not each other. Many frogs and toads depend on vocalizations to find mates, so figuring out how these tiny frogs persist as a species has not been an obvious task.

After confirming that the frogs can’t hear each other croak, researchers now suspect that the frogs have just become very visually oriented to compensate. Like some other frog species, they use gestures to court and communicate with each other, and some of those movements stem from the calls their ancestors used to listen to. As a result, some movements inadvertently make sounds, even if the real goal is to look good. It’s a reminder that evolution isn’t always perfectly efficient, as it only needs to work well enough to further a species’ reproductive chances. For many animals, making sounds you can’t account for would probably be a problem, but the pumpkin toadlets’ internal supply of poison apparently keeps them safe enough to keep sounding off without even knowing it.

Source: Why poison frogs don't poison themselves, Phys.org

On September 24th, 2017 we learned about

Tool-wielding monkeys are reshaping their local supplies of shellfish

A macaque monkey, like a human, doesn’t have the anatomy to pry open an oyster on its own. As nimble as our primate fingers are, they’re just not suited to opening these shellfish… unless they’re being used to hold a tool. Humans have created a lot of tools for this task, but macaque monkeys on NomSao and Koram, islands off the coast of Thailand, have shown you only need some rocks and know-how. Scientists following these monkeys have found that they’ve become quite adept at cracking open a variety of shellfish, with a single monkey consuming as many as 40 pieces of seafood a day. As humans (sort of?) know, that efficiency comes with a cost though, leaving the monkeys at risk for eating their favorite foods into oblivion.

Tradition of tool-use

Long-tailed macaque monkeys (Macaca fascicularis) are one of the few species of primates that use stone tools to help them work. While many animals use twigs and plants to help obtain resources, stone tools are of particular interest because of their durability, and their the parallels to early hominid tool creation. We’ve found examples of stone tools from generations ago, and eyewitness reports assert that these Thai monkeys have been using tools for at least 120 years. Researchers wondered if that was enough time for the monkeys to reshape their ecosystems like humans do, if on a smaller scale.

Obviously, researchers couldn’t go back in time to see the first day a monkey wielded a stone to crack open an oyster. Instead, they followed a larger population of monkeys on the island of Koram, and a smaller group living on NomSao. Both groups of monkeys used rocks to break open their shellfish, so the key point of comparison was population size. If tool-using monkeys were making an impact on their favorite foods, that impact would be magnified by more monkeys.

Larger impact of shrinking shellfish

This hypothesis proved true. NomSao had larger shellfish populations than the monkey-dense island of Koram. What’s more, the oysters, snails and other morsels were generally smaller on Koram, which is likely an effect of the monkeys’ targeted predation. If a smaller oyster is less likely to be munched by a monkey, then smaller oysters are more likely to survive and reproduce, eventually reducing the average size of these animals.

The monkeys may end up dealing with reductions of their own. If the shellfish are no longer abundant or big enough to be worth feeding on, the monkeys may have to find food elsewhere, abandoning their seafood diets. Researchers aren’t worried that the macaques will starve, but are curious about their tool use. Without reinforcement, or a way to preserve their techniques in writing like humans do, there’s a chance the monkeys will essentially forget their Stone Age advancements. That wouldn’t mean that tastier shellfish might rekindle the use of rocks in the future though- a separate study watching macaques found that they developed techniques to crack open oil palm nuts in less than a generation, as the nuts have only been in their area for 13 years.

My four-year-old asked: If the monkeys can’t eat oysters, will they eat bananas?

They might. Long-tailed macaques will eat just about anything they can, with fruits and seeds making the bulk of their diets. Thailand has a few different types of bananas, and while they don’t necessarily look like what turns up in western grocery stores, the monkeys probably still enjoy them from time to time.

Source: Tool-wielding monkeys push local shellfish to edge of extinction by Aylin Woodward, New Scientist