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Ancient Sri Lankans Figured Out How to Sustainably Hunt Monkeys and Squirrels

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Toque macaque monkeys grooming at the Royal Botanical Gardens, Peradeniya, Sri Lanka. (Credit: Viacheslav Misiurin/Shutterstock)

Some 45,000 years ago, the tropical rainforests of Sri Lanka teemed with dangerous plants and lacked big game, yet people made a life there. Our key to success in that seemingly inhospitable region? It was monkeys and squirrels, researchers say — or rather, our ability to catch them.

“These animals are difficult to catch and suggest a certain level of sophistication in terms of hunting strategies,” said Patrick Roberts, an archaeologist at the Max Planck Institute for the Science of Human History in Jena, Germany, who led the new research.

The discovery suggests humans had the capacity to quickly adapt to unfamiliar environments. This knack for adaptation may be what enabled people to expand across the planet, the researchers say.

Extreme Environments

Some researchers argue that as humans dispersed out of Africa, our ancestors tended to stick to savannas and grasslands where medium- to large-sized game was available to hunt. Otherwise, early humans followed coastal routes where food resources were predictable. But settling down in the heat and humidity of tropical rainforests where food is relatively scarce seemed an unlikely choice.

Yet, in the last 20 years, archaeologists have uncovered evidence that humans were present in the tropical rainforests of Sri Lanka, Southeast Asia and Melanesia at least 45,000 years ago and relied on the rainforests’ resources year round. “What were they eating? And how did they obtain this food?” Roberts wondered.

Appetizing Apes

Roberts and colleagues analyzed more than 14,000 animal bones and tooth fragments from Fa-Hien Lena Cave, the earliest known archaeological site with evidence for human behavior in Sri Lanka. The researchers looked for cut marks on the bones that would have suggested the animals were butchered and inspected the bones for evidence of burning. They also examined small stone and bone tools to get an idea of how early humans might have used them to hunt.

Monkeys and tree squirrels accounted for more than 70 percent of the animal remains, the researchers report today in the journal Nature Communications. When the scientists examined monkey tooth fragments, they found early human hunters were targeting adult monkeys in their prime. Previous research suggested early humans used traps to hunt small game, but that strategy would have ensnared animals of all ages.

“This was the first time we had clear evidence for focused [hunting],” Roberts said.

It also appears that the ancient Sri Lankans were able to devise sustainable hunting strategies, based on evidence that the ancient hunters coexisted with their prey for tens of thousands of years without driving them extinct.

In an intriguing twist, Roberts and his team also discovered monkey bones became hunting weapons. “Fascinatingly, the bone tools were made from [the long bones] of the monkeys and then apparently used to hunt the same monkeys!” Roberts said.

“It is clear that human populations were so successful because they gained intimate knowledge of each environment and [understood] the ecosystem dynamics of each setting,” Roberts said, a stark contrast to modern times, where “through our consumer choices, a significant portion of the world’s population impacts environments thousands of kilometers away from them.”

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Ecology

What if a jolt of electricity could make you happy?

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Scientists found a way to literally spark joy using joly of electricity. (Credit: icon99/shutterstock)

Scientists found a way to literally spark joy using jolts of electricity. (Credit: icon99/shutterstock)

People all around the world (or at least where Netflix is available) have been exhausting themselves of late trying to “spark joy” in their lives. The urge comes from cleaning guru Marie Kondo, whose philosophy rests on the principle that we should rid our homes and minds of things that don’t inspire bursts of pleasure.

The message resonates, in part, because it ties positivity to the world of material things. Happiness is in our minds. So having a tangible mechanism for producing joy is understandably comforting.

But there’s a simpler way to spark joy, if we really want to get literal about it. Any emotion we feel has a physical cause inside our brains. Electrical charges pass from neuron to neuron, spreading ripples of thought and feeling. What we call happiness is just electricity. And now researchers say they’ve found a remarkably specific means of triggering the electrical fireworks that add up to happiness in our brains. By electrically stimulating a brain region known as the cingulum, scientists created spontaneous laughter and a sense of calm and joy in three different patients.

The find could lead to treatments for anxiety and depression, and it hints at insights into the very roots of our emotions themselves.

An artist's illustration shows how an electrode tapped into the cingulum. (Credit: From Bijanki et al, J. Clin. Invest. (2019). Courtesy of American Society for Clinical Investigation)

An artist’s illustration shows how an electrode tapped into the cingulum. (Courtesy of American Society for Clinical Investigation)

Unexpected Bliss

The young woman is clad in hospital garb, sitting upright in a bed. A white hospital cap mushrooms above her head, wires splay from its rear. She’s due for brain surgery in a few days to treat a difficult, disruptive kind of epilepsy. She’s been worried and anxious.

She breaks into a radiant smile, laughter flowing uninhibited.

“I’m kind of like smiling because I can’t help it,” she says. A bit later, “Sorry, that’s just a really good feeling. That’s awesome.”

Neuroscientists just administered a tiny jolt of electricity to wires threaded through her skull and into her brain. The wires are there to guide surgeons to the source of her seizures. But before the procedure, she’s agreed to play guinea pig to a team of Emory University researchers.

Patients like her offer an unprecedented opportunity for researchers to test the workings of various brain regions with unparalleled specificity. By delivering targeted bursts of electricity through the electrodes, they can watch what happens when specific neural circuits are activated.

The team was sending small bursts of electricity to her cingulum, a horseshoe of brain matter that links to regions associated with emotion, self-assessment, social interaction and motivation, among other things. It’s also known to regulate anxiety and depression.

This kind of research, though hardly common, is not new. The patient’s reaction is.

“It was really exciting,” says Kelly Bijanki, a neuroscientist at Emory University who studies behavioral neuromodulation. She was one of the scientists working with the young woman, whose name was not given for privacy reasons, that day. She says the kind of spontaneous joy she saw was unprecedented.

Experiments with brain stimulation have elicited laughter and smiles before. But those responses seemed mechanical. Bijanki says the patients usually described it as a purely motor response. “Their body has laughed, but there’s no content to it.”

This case was different. There was real warmth behind the laughter; true happiness in her voice. At one point, the patient reported she was “so happy she could cry,” the researchers write in their paper.

“The way she was laughing was really infectious,” Bijanki says. “The whole room felt different: she was laughing, she was having a good time, and not afraid. Just that social, emotional contagion took over.”

Further tests confirmed the response. They conducted sham trials, telling the patient that they were providing stimulation when they weren’t. She didn’t react. They tested various levels of stimulation and saw that the more electricity they delivered, the stronger the joyous reaction was. The pattern remained the same: An initial burst of exultation faded into a state of happy relaxation after several seconds.

The researchers found no drawbacks to the treatment, either, they report in a paper in the Journal of Clinical Investigation. Her language skills and memory remained perfectly intact, and they saw no ill aftereffects of the stimulation.

In a screengrab from the scientists' experiment, the patient feels overwhelming joy even while pondering her dog dying. (Credit:)

In a screengrab from the scientists’ experiment, the patient feels overwhelming joy even while pondering her dog dying. (Credit: Bijanki et al, Journal of Clinical Investigation)

Put to the Test

The woman’s impending surgery would require her to remain awake while surgeons probed inside her skull. Their goal was to cut out the tissue responsible for her epilepsy, but it’s a game of millimeters. Doctors must remove enough to ensure that seizures don’t recur, but without causing permanent harm. The patient’s seizures appeared to emanate from a region near to language processing centers. Her job was to stay awake while surgeons worked, reading and talking to ensure they wouldn’t excise anything important.

The brain stimulation turned out to work so well that doctors were able to cut out completely the drugs used to manage anxiety during this type of brain surgery. Those medications can make patients sleepy and unresponsive, so the anesthesiologist decided to stop them midway through. The young woman, her skull opened to surgical tools, breezed through.

“During the surgery … she was telling me jokes about her dad, where prior to turning on the stimulation she had been crying and hyperventilating and right on the edge of panic,” Bijanki says.

To confirm their findings, the researchers performed the same tests with two more epilepsy patients with electrodes similarly implanted in their skulls. They got the same results. Jabs of electricity literally sparking joy inside their heads.

Putting Happiness to Work

It’s too simplistic to say the researchers have stumbled upon the place where joy hides within us. The brain is complex, and emotions well up from more than just a single place. Multiple brain regions are involved, and each contributes a facet to the emotion that we come to know as happiness.

In fact, researchers have found joy in another place in the brain as well. Sameer Sheth, a neurosurgeon at the Baylor College of Medicine, says that he’s had patients report feelings of euphoria during the course of his own work with brain stimulation as well. He was working with the ventral striatum, a region separate from the cingulum, though the two are tightly connected.

Stimulation to the ventral striatum has also produced the same sort of laughter and mood elevation that Bijanki saw, Sheth says.

But just because emotions are neurologically complex doesn’t mean there’s no value to understanding their origins.

“The more we understand this circuitry, the more we can fine tune how to harness that capability within an individual and the better we’ll be able to treat patients with mood disorders,” Sheth says.

Bijanki sees a range of applications for brain stimulation aimed at specific targets, beginning with the kind of surgeries the young epileptic was undergoing. By precluding the use of sedatives, the find might give brain surgeons new options when performing the kind of procedures the young woman went through. Allowing patients to give more feedback could make brain surgeries more targeted. It might also expand the scope of neurosurgery.

“The definition of what is an inoperable tumor is in some circumstances related to what is the surgeon reasonably comfortable with removing that isn’t going to ruin the patients life,” Bijanki says. “If the surgeon could know that in real time, then the surgery could proceed a little bit differently.”

More broadly, it could also find use as a treatment for mental disorders like depression, anxiety and PTSD. Bijanki imagines electrodes powered by a pacemaker battery delivering continuous, low-grade stimulation to patients with depressive disorders.

In the future, we may not even need wires to spark such emotions. Scientists are developing means of activating brain regions with pulses of light, or with ultrasound. Flashes and vibrations could one day deliver ease to the afflicted.

There are drugs that accomplish similar things today, of course, but those often have side effects, and the treatment isn’t always as direct. Brain stimulation could offer a better path.

Banish the Sadness

Bijanki was also struck by an odd side-effect of the stimulation. Though patients had no trouble recalling sad memories during treatment, the recollections were wholly powerless to make them feel unhappy.

“I remember my dog dying, and I remember that it was a sad memory, but I don’t feel sad about it right now,” the young woman said, as reported by the researchers in their paper. Another patient concurred, unable to recollect a tragic memory without smiling. The effect is slightly jarring, but it could provide a shield of sorts to those overcoming trauma.

Those suffering from PTSD often go through what’s called exposure therapy, where they are asked to repeatedly sift through memories of a traumatic event. The goal is to drain those memories of their fearsome power over time, but it is difficult, frightening work.

Paired with temporary brain stimulation that elides sadness, Bijanki thinks PTSD patients might be far better equipped to tread through painful memories.

Finding Balance

Ultimately, however, the goal of therapies involving brain stimulation isn’t to wipe out negative emotions.

Anger, sadness and fear are not without their merits, and banishing them could have unintended consequences. Sadness sits at the other end of the spectrum from happiness, for example. Taking away any of our emotions would be removing an aspect of our humanity. What’s more, we have emotions for a reason.

“Our emotions exist for a very specific purpose, to help us understand our world, and they’ve evolved to help us have a cognitive shortcut for what’s good for us and what’s bad for us,” Bijanki says.

That’s not the goal here, of course, though discussions about the ethical use of such technologies in the future is certainly warranted. Bijanki says that we’d need to be careful about applying things like brain stimulation that could be abused.

But, she’s not very worried about electrodes and electric shocks becoming the next designer drug. It’s just too technically demanding, she says. And the potential benefits for those with depression and other conditions are great.

Sometimes the bad can outweigh the good. In those cases, sparking a little joy might be what we need.

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NASA Picks Science Experiments to Send to the Moon This Year

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Virgin Galactic’s SpaceShipTwo Just Made its Second Trip to Space

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SpaceShipTwo under rocket power

SpaceShipTwo is carried into the air on the back of a plane, but then takes off into space under its own power. (Credit: Virgin Galactic)

On Friday, Virgin Galactic’s SpaceShipTwo flew in space for the second time, taking off from Mojave, California after days of weather delay. SpaceShipTwo took off at 8:07 a.m. PST carrying two pilots, a crewmember, and a nearly full weight of science projects from NASA.

Unlike most spaceflights that fire rockets from the ground, SpaceShipTwo is carried on the belly of a plane named WhiteKnightTwo before being released to propel itself into the upper atmosphere. After being carried 45,000 feet into the air, SpaceShipTwo successfully fired its rocket engine and reached suborbital space at approximately 8:55 a.m. PST. It coasted there for only a few minutes before heading back toward the ground, where it landed much like any other plane, roughly an hour after takeoff. Like all of SpaceShipTwo’s planned flights, this one was suborbital, meaning it does not reach orbit, and attains weightlessness for only a few minutes during its trip.

SpaceShipTwo made its maiden space voyage in December 2018, and today was its fifth powered flight in total. Unlike other private spaceflight companies like SpaceX, Virgin Galactic has made their main goal ferrying private citizens into space, and have been taking reservations for years.

The third crewmember today was Virgin Galactic’s Chief Astronaut Instructor and cabin evaluation lead. Her job today was to see how SpaceShipTwo feels from the cabin. Eventually, Virgin Galactic hopes to seat six passengers in place of the science payloads – or alongside them.

The spacecraft today also carried research projects from NASA’s Flight Opportunities program, which pairs research institutions with private companies who can fly their projects into space. The combined weight of the payloads put SpaceShipTwo at close to, but just under, the requirements for the commercial launch weight that NASA has specified. One of Virgin Galactic’s goals during this flight was testing how the vehicle flies with a greater weight distribution. Details will likely come later, but the flight was successful, which bodes well for the craft’s future in ferrying cargo as well as passengers.

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