Orangutans sacrifice sleep to socialize–but naps can help
If you've ever had a late night out with friends and then needed an afternoon lie-down the next day, you're in good primate company. Wild orangutans also nap to make up for lost sleep, according to new research on an orangutan population in Indonesia. And, one of the biggest factors determining how much sleep they get is their social environment, per the study published June 25 in the journal Current Biology.
Orangutans are considered semi-solitary great apes, meaning that they have their own individual ranges, and– with the exception of mothers and infants– spend lots of their days alone. However they still socially interact, voluntarily spending upwards of half their time in proximity to others, depending on sex and life stage. In contrast to humans, who evolved in hunter-gatherer groups, orangutans come from a more solitary lineage. Still socializing seems really important to the apes, as emphasized by the new findings. When the orangutans opt to spend the night near others, they get less rest and take more naps the next day, the scientists report. Yet despite the lost sleep, orangutans still often choose to build their nightly nests in close proximity to each other.
'They definitely seem to have control over who they spend time with,' Caroline Schuppli, a study co-author and an evolutionary biologist and research group leader at the Max Planck Institute of Animal Behavior in Konstanz, Germany, tells Popular Science. 'If they really needed a night to themselves, they could make sure that they got that. To me, the result just shows how vital social associations are, even for this semi-solitary species. … It's not something they can just give up on because they sleep less.'
The new research also reveals other surprising parallels between human and orangutan sleep habits. Nap length, the influence of temperature and travel, and even a bed-making pre-sleep routine among orangutans all mirror our own tendencies– adding to the ever-growing list of shared traits between us and our orange-furred cousins.
'We can learn a lot about the evolutionary history of sleep by studying it in the settings in which it evolved,' Schuppli says.
Between 2007 to 2023, Schuppli and a crew of local field assistants in Indonesia spent hundreds of days and nights following individual orangutans from their early morning wakeups through to their evening bedtimes and beyond. To ensure thorough tracking, three people were assigned to monitor each orangutan. Armed with binoculars and with their necks craned towards the treetops as they trekked through swampy, Sumatran peat forest, the team collected data on 53 adult individuals over the course of the 17 years.
Each evening, before turning in for the night, orangutans 'make their beds,' building leafy nests of twigs and foliage to rest on. The researchers observed that this particular population of orangutans also build slightly simpler nests for daytime naps, in contrast to other groups which frequently just laze on bare branches.
To approximate sleep time, the scientists recorded how long each individual spent quietly lying still in these nests in each instance. On average, each night the orangutans entered their nests around 5:40 p.m., less than an hour before sunset, and left them just after sunrise at around 6:28 a.m.–spending just under 13 hours 'in bed.'
At least one study of captive orangutans has previously shown that the primates spend about 75 percent of their quiet time in their nests sleeping, so 13 hours of nest time comes out to less than 10 hours of estimated nightly sleep. The apes also spent a mean total of 76 minutes napping each day, over 1-2 different nests and multiple bouts of rest. The average nap duration was about 10 minutes.
'It's surprisingly similar to what is recommended in humans for the length of a power nap,' says Schuppli.
Beyond these basic sleep stats, the scientists also tabulated how the length of one resting bout influences the next, based on the many instances where they were able to follow the same orangutans across two or more days. They further compared the time spent in nests against environmental and social variables like temperature, rainfall, the proximity of other orangutans, length of daily travel, and amount of food eaten.
They found that the orangutans don't seem to make up for a shortened night's sleep with more rest the next night. Instead, they compensate with naps. For every hour of lost nighttime nest rest, the apes showed a 12.3 percent increase (about 10 extra minutes) in their amount of daytime dozing. 'There's some kind of nap quota they're maybe trying to fulfill,' Schuppli explains.
The population of orangutans followed in the study is unique in its routine tool use and level of sociality—both things that require a lot of cognitive energy. Thus getting enough sleep is likely especially important in this group, she adds.
[ Related: These orangutans indulge in a spa-like skincare routine. ]
Many scientists have observed orangutans and other primates over the years, following and meticulously recording their daytime activity. But this new research proves that understanding nighttime inactivity can similarly illuminate our understanding of our closest relatives on the tree of life. 'It is cool to start to actually dig into the almost half their lives that they're asleep,' Alison Ashbury, lead study author and also an evolutionary biologist at the Max Planck Institute, tells Popular Science. 'This whole question of sleep in wild animals is becoming a bigger research topic, as we get more technology and we're able to actually [examine it],' she says.
Among all the variables examined, the largest single determiner in how long an individual spent in its nest each night was the presence or absence of other orangutans. For every additional, so-called association partner nesting nearby, an orangutan's sleep period was about 14 minutes shorter. The primary driving factor here seemed to be wake-up time. 'They get out of their nests earlier when they're with others… as soon as the first one leaves, everybody leaves,' she notes. Schuppli and her colleagues are not yet sure why orangutans opt to sacrifice rest for social sleep, but it could be because it reinforces bonds during waking hours, as observed in a 2024 study of baboons.
Temperature also played a significant role, with extremes reducing rest periods. 'As it gets colder at night they sleep less, and as it gets hotter during the day they sleep less. So there's some sort of ideal range for sleeping,' just like in humans, says Ashbury. Plus, the more an orangutan traveled during the day, the less they got to sleep, generally because of a later bedtime. Relatably, on rainy days, the apes napped more.
The study authors were unable to measure the orangutans' sleep directly, relying instead on the proxy of nest time. So, it's possible the exact sleep numbers would differ if actual snooze time was easily quantified, without disturbing the wild primates. It's also likely that there were differences night-to-night in quality and depth of sleep that the researchers weren't able to capture, as well as environmental variables beyond the scope of what they assessed.
Yet all in all, the results highlight just how critical sleep and socializing are for orangutans, and how the environment can shape restorative rest. What applies for other apes is best kept in mind for ourselves as well, says Schuppli.
'You shouldn't be ashamed if you need a nap during the day.'
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
19 hours ago
- Yahoo
Orangutans sacrifice sleep to socialize–but naps can help
If you've ever had a late night out with friends and then needed an afternoon lie-down the next day, you're in good primate company. Wild orangutans also nap to make up for lost sleep, according to new research on an orangutan population in Indonesia. And, one of the biggest factors determining how much sleep they get is their social environment, per the study published June 25 in the journal Current Biology. Orangutans are considered semi-solitary great apes, meaning that they have their own individual ranges, and– with the exception of mothers and infants– spend lots of their days alone. However they still socially interact, voluntarily spending upwards of half their time in proximity to others, depending on sex and life stage. In contrast to humans, who evolved in hunter-gatherer groups, orangutans come from a more solitary lineage. Still socializing seems really important to the apes, as emphasized by the new findings. When the orangutans opt to spend the night near others, they get less rest and take more naps the next day, the scientists report. Yet despite the lost sleep, orangutans still often choose to build their nightly nests in close proximity to each other. 'They definitely seem to have control over who they spend time with,' Caroline Schuppli, a study co-author and an evolutionary biologist and research group leader at the Max Planck Institute of Animal Behavior in Konstanz, Germany, tells Popular Science. 'If they really needed a night to themselves, they could make sure that they got that. To me, the result just shows how vital social associations are, even for this semi-solitary species. … It's not something they can just give up on because they sleep less.' The new research also reveals other surprising parallels between human and orangutan sleep habits. Nap length, the influence of temperature and travel, and even a bed-making pre-sleep routine among orangutans all mirror our own tendencies– adding to the ever-growing list of shared traits between us and our orange-furred cousins. 'We can learn a lot about the evolutionary history of sleep by studying it in the settings in which it evolved,' Schuppli says. Between 2007 to 2023, Schuppli and a crew of local field assistants in Indonesia spent hundreds of days and nights following individual orangutans from their early morning wakeups through to their evening bedtimes and beyond. To ensure thorough tracking, three people were assigned to monitor each orangutan. Armed with binoculars and with their necks craned towards the treetops as they trekked through swampy, Sumatran peat forest, the team collected data on 53 adult individuals over the course of the 17 years. Each evening, before turning in for the night, orangutans 'make their beds,' building leafy nests of twigs and foliage to rest on. The researchers observed that this particular population of orangutans also build slightly simpler nests for daytime naps, in contrast to other groups which frequently just laze on bare branches. To approximate sleep time, the scientists recorded how long each individual spent quietly lying still in these nests in each instance. On average, each night the orangutans entered their nests around 5:40 p.m., less than an hour before sunset, and left them just after sunrise at around 6:28 a.m.–spending just under 13 hours 'in bed.' At least one study of captive orangutans has previously shown that the primates spend about 75 percent of their quiet time in their nests sleeping, so 13 hours of nest time comes out to less than 10 hours of estimated nightly sleep. The apes also spent a mean total of 76 minutes napping each day, over 1-2 different nests and multiple bouts of rest. The average nap duration was about 10 minutes. 'It's surprisingly similar to what is recommended in humans for the length of a power nap,' says Schuppli. Beyond these basic sleep stats, the scientists also tabulated how the length of one resting bout influences the next, based on the many instances where they were able to follow the same orangutans across two or more days. They further compared the time spent in nests against environmental and social variables like temperature, rainfall, the proximity of other orangutans, length of daily travel, and amount of food eaten. They found that the orangutans don't seem to make up for a shortened night's sleep with more rest the next night. Instead, they compensate with naps. For every hour of lost nighttime nest rest, the apes showed a 12.3 percent increase (about 10 extra minutes) in their amount of daytime dozing. 'There's some kind of nap quota they're maybe trying to fulfill,' Schuppli explains. The population of orangutans followed in the study is unique in its routine tool use and level of sociality—both things that require a lot of cognitive energy. Thus getting enough sleep is likely especially important in this group, she adds. [ Related: These orangutans indulge in a spa-like skincare routine. ] Many scientists have observed orangutans and other primates over the years, following and meticulously recording their daytime activity. But this new research proves that understanding nighttime inactivity can similarly illuminate our understanding of our closest relatives on the tree of life. 'It is cool to start to actually dig into the almost half their lives that they're asleep,' Alison Ashbury, lead study author and also an evolutionary biologist at the Max Planck Institute, tells Popular Science. 'This whole question of sleep in wild animals is becoming a bigger research topic, as we get more technology and we're able to actually [examine it],' she says. Among all the variables examined, the largest single determiner in how long an individual spent in its nest each night was the presence or absence of other orangutans. For every additional, so-called association partner nesting nearby, an orangutan's sleep period was about 14 minutes shorter. The primary driving factor here seemed to be wake-up time. 'They get out of their nests earlier when they're with others… as soon as the first one leaves, everybody leaves,' she notes. Schuppli and her colleagues are not yet sure why orangutans opt to sacrifice rest for social sleep, but it could be because it reinforces bonds during waking hours, as observed in a 2024 study of baboons. Temperature also played a significant role, with extremes reducing rest periods. 'As it gets colder at night they sleep less, and as it gets hotter during the day they sleep less. So there's some sort of ideal range for sleeping,' just like in humans, says Ashbury. Plus, the more an orangutan traveled during the day, the less they got to sleep, generally because of a later bedtime. Relatably, on rainy days, the apes napped more. The study authors were unable to measure the orangutans' sleep directly, relying instead on the proxy of nest time. So, it's possible the exact sleep numbers would differ if actual snooze time was easily quantified, without disturbing the wild primates. It's also likely that there were differences night-to-night in quality and depth of sleep that the researchers weren't able to capture, as well as environmental variables beyond the scope of what they assessed. Yet all in all, the results highlight just how critical sleep and socializing are for orangutans, and how the environment can shape restorative rest. What applies for other apes is best kept in mind for ourselves as well, says Schuppli. 'You shouldn't be ashamed if you need a nap during the day.'
Yahoo
2 days ago
- Yahoo
Your Brain Is Glowing Right Now. Literally.
Here's what you'll learn when you read this story: The human brain actually lights up with signals known as ultra weak photon emotions (UPEs), which are a byproduct of metabolic processes. Researchers have now been able to detect UPEs and determine what they were revealing about brain function. A new imaging technique called photoencephalography could someday harness UPE signals as a diagnostic tool to supplement PET scans and MRIs. From bioluminescent mushrooms in the undergrowth of a rainforest to alien sea creatures eerily glowing in the abyssal depths, glowing organisms light up some of the darkest places on Earth. But humans aren't among them—or, at least, we thought so. As a team of researchers—led by Haley Casey from Algoma University in Ontario, Canada—found out, the human brain can actually luminesce. They called these glimpses of light ultra weak photon emissions (UPEs), and they are a result of metabolic energy flow. As electrons degrade during a process known as oxidation, they lose energy and release photons with it. Our brains emit them in visible light, meaning that if we had the X-ray vision to see through each other's skulls in total darkness, we might be able to make out a faint glow. This is not technically bioluminescence—organisms that are bioluminescent rely on chemicals such as luciferin for their eerie light. It also isn't phosphorescence, which is absorbed energy released in the form of light. It isn't even thermal radiation, which can be seen in infrared and is emitted by anything over a temperature of absolute zero. UPEs are their own phenomenon, and can be detected from the outside. They can also be indicators of what is going on in the brain. '[UPEs] predict oxidative stress, aging, and neurodegeneration,' Casey and her research team said in their study, recently published in the journal Current Biology. 'UPEs are triggered by neurotransmitters and biophysical stimuli, but they are also generated by cells at rest and can be passively recorded using modern photodetectors in dark environments.' Previous studies found that the human body is capable of glowing, but Casey's team specifically zeroed in on the brain and what these emissions could tell us about brain activity and health. They also were trying to prove that UPE signals from the brain could be distinguished from background photon noise. Subjects wore an EEG cap that had electrodes attached, along with photomultiplier tubes, to monitor brain activity. Photomultiplier tubes are so hypersensitive that they can pick up even the faintest trace of light. What the researchers were testing out was a new technique they devised (still in development) called photoencephalography. There are two major advantages of using photoencephalography over other methods (like PET scans and even less invasive fNIRS and fMRI scans): it is non-invasive, and it is less likely that results will be confused by the test itself. Other methods can either spark neural activity or suppress it, but photoencephalography does neither. As a result, passive measurement of brain activity is undisturbed and allows for detection of electromagnetic stimuli in the surrounding environment. Searching for UPE signals, the researchers focused on the left occipital lobe of the brain (which specializes in visual processing) and the right temporal lobe (which is instrumental to learning and remembering nonverbal information such as music). They were curious as to whether UPE signals from either lobe would show up as distinct from background noise, and when compared to background photons, the signals from the brain did in fact stand out as a result of their unique frequency. In the dark, subjects were also given sound-based tasks to accomplish without needing to see what they were doing. They were told to open and close their eyes before and after listening to music. UPEs were logged during tasks done with open and closed eyes—both of which have obvious brain signatures. There were variations in UPE output depending on the task being performed, and the activity detected by the EEG cap was also highly correlated with UPE signals. UPEs could possibly help with diagnosing neurological conditions in the future. 'Because UPEs are related to oxidative metabolism, the most immediately relevant applications might include the detection of budding brain tumors, excitotoxic lesions, mild traumatic injuries, and neurotoxic insults,' Casey said. Photoencephalography won't be replacing MRIs just yet, but it will someday shine a light on what we couldn't see before. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
CNN
2 days ago
- CNN
Drone footage reveals orcas using tools in a stunning first
Editor's Note: Call to Earth is a CNN editorial series committed to reporting on the environmental challenges facing our planet, together with the solutions. Rolex's Perpetual Planet Initiative has partnered with CNN to drive awareness and education around key sustainability issues and to inspire positive action. CNN — Behavioral ecologist Michael Weiss was browsing through new drone footage of the orca pods he studies in the Salish Sea when he spotted one of the killer whales carrying something green in its mouth and noticed an unusual behavior: Some orcas were rubbing against each other for up to 15 minutes at a time. At first, Weiss didn't think much of it 'because whales do weird things,' he said. But more observations yielded similar sights on his drone camera. 'I zoom in, and sure enough, there's clear as day this piece of kelp that they're using to rub on each other.' Over the course of just two weeks in 2024, Weiss and his team documented 30 examples of these curious interactions. They found that the southern resident orcas — a distinct population of killer whales — were detaching strands of bull kelp from the seafloor to roll between their bodies in a behavior the scientists dubbed 'allokelping.' Allokelping could be a form of grooming for skin hygiene, as well as a way to socially bond with other members of the pod, the researchers reported in a new paper published Monday in the journal Current Biology. The discovery marks the first time cetaceans — marine mammals including whales, dolphins and porpoises — have been observed using an object as a tool to groom. Across the animal kingdom, using tools is rare, according to behavioral ecologists. But when it does happen, it's often for finding food or attracting mates. 'This is a quite different way of using an object,' said Weiss, the study's lead author and research director of the Center for Whale Research in Washington state. Allokelping theories There are two possible reasons behind the allokelping behavior, Weiss and his team hypothesize. Hygiene, such as treating or removing dead skin, could be one explanation. Cetaceans often shed dead skin, which helps keep their bodies smooth and aerodynamic. Skin lesions, particularly gray patches, are becoming more prevalent in southern resident orcas, Weiss added, so allokelping might be a way to treat those lesions. The other hypothesis, Weiss explained, is that allokelping is a way to strengthen social bonds, as the whale pairs seen exhibiting this behavior were usually close relatives or similar in age. 'These guys are incredibly socially bonded,' said Deborah Giles, an orca scientist at the SeaDoc Society who was not involved with the research. This behavior is fascinating but not entirely surprising, she added. Orcas are curious and tactile, with brains that are large compared with their body size, Giles explained, adding that some parts of the killer whale brain are more developed than what's seen in humans. Each orca population even has its own dialect. Cetaceans also have sensitive skin, explained Janet Mann, a behavioral ecologist at Georgetown University who has studied marine mammals for 37 years. Orcas are known to rub on other objects such as smooth-pebble beaches in Canada, or on algal mats. But it's unusual to see two individual killer whales using a tool to seemingly exfoliate each other, she said. 'What (the study) shows is that we know very little about cetacean behavior in the wild,' Mann said. Allokelping likely wouldn't have been discovered without advances in drone and camera technology, which have opened up 'a whole new world' for scientists to better understand cetaceans' complex lifestyles, Mann said. Historically, whales are observed from shore or from boats, offering a limited perspective of what's happening in the water. But drones offer a bird's-eye view of what marine animals are doing just below the surface. It's likely this population has been allokelping for a while, she said — only now we can see it. Cultural phenomenon Orca scientists with drone footage are probably going to be on the lookout for this sort of behavior now, Giles said. Killer whales aren't the only cetaceans known to use tools, though. Some bottlenose dolphins have been observed carefully removing and using sponges to scare up prey on the seabed, a sophisticated behavior that only a small fraction of the population exhibits, said Mann, who has studied the dolphins in Australia's Shark Bay. Some other bottlenose dolphins use their tails to slap the ground in a circle, creating mud-ring plumes that trap fish. And humpback whales have long used bubble nets to catch prey. Whether these examples constitute 'using tools' is a topic of debate in the scientific community, but regardless, they are all behaviors related to foraging for food. What makes allokelping unique is its potential benefits for skin health and relationships — in other words, it appears to be a cultural practice. 'This idea of allogrooming (with tools) is largely limited to primates, which is what makes it remarkable,' said Philippa Brakes, a behavioral ecologist with the nonprofit Whale and Dolphin Conservation who was not involved with the research. 'This kind of feels like a moment in time for cetaceans, because it does prove that you don't necessarily need a thumb to be able to manipulate a tool.' Brakes, who studies social learning and culture in cetaceans, added that this new research 'tells us quite a lot about how important culture is for these species.' Each population — in this case, southern resident orcas — has a distinct dialect for communication, specific foraging strategies and now a unique type of tool use. In a rapidly changing environment, Brakes said, 'culture provides a phenomenal way for animals to be able to adapt,' as it has for humans. 'It's more reason to ensure that we protect their habitat as well as their behavior,' she noted. A 'completely novel' find Indeed, southern resident killer whales are critically endangered and federally protected both in the United States and Canada, with a total population of just 74 whales. And as bull kelp is in decline due to human activities that disrupt the seabed and more frequent heat waves caused by climate change, the overall ecosystem is degrading. Kelp forests are also critical nursery habitat for juvenile chinook salmon — a key part of killer whales' diet, Giles said. Southern residents have been spending less and less time in the Salish Sea over the years, possibly because of dwindling prey, said Monika Wieland Shields, cofounder and director of the nonprofit Orca Behavior Institute. 'This study makes me wonder if one of the reasons the Southern Residents continue to visit the Salish Sea periodically even during times of low salmon abundance is to engage in allokelping,' Shields wrote in an email to CNN. The research is now leading to new areas of study. 'This cetacean data point is a really important one because it's completely novel,' said Dora Biro, an animal cognition researcher at the University of Rochester who was not involved with the study. Biro, who has mostly studied tool use in wild chimpanzees, added that examples of terrestrial tool use are much more widespread than in aquatic environments. She is now working on a grant proposal with Weiss' team to better understand the purpose of the behavior. But for Brakes, there doesn't necessarily need to be a purpose: 'The objective may just be social bonding, and that would still make it a tool.'
