Monkey sleep, monkey do: how primates choose their trees
December 31, 2014
Primates don’t monkey around when deciding where to spend the night, but primatologists have had a poor grasp on what drives certain monkeys toward specific trees. Now, two extensive studies of Indonesian primates suggest that factors in selecting trees each evening are site-specific and different for each species—and that some overnight spots result in conflicts between monkeys and humans.
“We have to understand what monkeys need [in order] to sleep to know what we have to protect,” said primate scientist Fany Brotcorne of the University of Liège in Belgium, leader of one of the research teams, in an interview with mongabay.com.
When monkeys choose their evening perch, they weigh more than just comfort. The main factors scientists suspect are safety from predators, distance to feeding grounds, human interactions, insect avoidance, and competition with other primates.
“Primates may be spending up to 12 hours at their sleeping sites, and yet we really don’t know much about them,” said Adrian Barnett of the University of Roehampton, in London, U.K., a primatologist not involved in the new work, in an email to mongabay.com.
The two unaffiliated studies occurred on neighboring Indonesian islands. Brotcorne’s team spent 56 nights in the Bali Barat National Park in Bali studying long-tailed macaques (Macaca fascicularis), a thriving primate species. In West Kalimantan on the island of Borneo, primatologist Katie Feilen of the University of California at Davis followed the sleeping behaviors of endangered proboscis monkeys (Nasalis larvatus) for 132 nights.
Both groups noted the sizes and shapes of trees favored by the monkeys. Brotcorne’s group also measured the distance between sleeping sites and human outposts such as temples, tourist areas, or roads.
The proboscis monkeys returned each night to tall, isolated trees near rivers. The monkeys gather in trees that jut above the canopy to avoid predators and insects, believes Feilen. Predators can’t crawl from tree to tree toward the monkeys if the trees’ branches don’t touch. At the same time, the monkeys’ lofty—and windy—perches help them avoid malaria-ridden mosquitoes that tend to remain within the canopy.
“I think insect and disease ecology plays a bigger role in all these questions of primatology than we are all thinking,” said Feilen.
The long-tailed macaques snoozed away in trees near human-modified areas. Brotcorne suspects food availability was the main factor driving the macaques’ bunk choice. The monkeys scooted closer to a Hindu temple and tourist area where fruit, rice, and crackers abounded during the peak tourist season. The timing of their move also coincided with the start of the dry season and a decline in natural fruit production. The two teams reported their findings side-by-side this month in the American Journal of Primatology.
There is not just one evolutionary force influencing sleeping tree preference for primates, pointed out both lead authors.
“Both papers are significant in that they are showing the importance of sleeping sites in primate ecology,” said Barnett. “What is needed is a collation of data that is sufficiently broad to allow general theories to be put up [about sleeping tree selection].”
The distinct sleeping site chosen by the two species also influences the primates’ interactions with humans. Loggers preferentially remove the tall riverside trees favored by the endangered proboscis monkeys, threatening the species’ habitat, said Feilen. The proboscis monkeys she studied had to contend with deforestation by mining and palm oil companies. Also, local hunters knew where to find the predictable primates.
On the other hand, macaques and humans have competed for space and food in human-modified areas for centuries. But their close contact worries Brotcorne because diseases can cross from monkeys to humans and vice versa. Human food is not the healthiest diet for monkeys, she added.
“If you go to the tourist monkey forests, you will see obese monkeys,” said Brotcorne.
Feilen, K., and A. Marshall. 2014. Sleeping site selection by proboscis monkeys (Nasalis larvatus) in West Kalimantan, Indonesia. American Journal of Primatology 76: 1127-1139.
Brotcorne, F., C. Maslarov, N. Wandia, A. Fuentes, R. Beudels-Jamar, and M. Huynen. 2014. The role of anthropic, ecological, and social factors in sleeping site choice by long-tailed Macaques (Macaca fascicularis). American Journal of Primatology 76: 1140-1150.
Leigh Cooper is a graduate student in the Science Communication Program at the University of California, Santa Cruz.
This video from India says about itself:
20 December 2014
Kanpur Central Railway Station. Monkey saves friend’s life without any human help.
From the Deccan Herald in India:
Monkey saves ‘dying’ friend at Kanpur Railway station (Video)
New Delhi, Dec 21, 2014, Agencies:
A friend in need is a friend indeed: A hair-raising video that has surfaced on YouTube illustrates this proverb very well. In the video, a monkey could be seen trying to save another monkey lying unconscious on a railway track.
The monkey in the video is surely impressive for its presence of mind and efforts to help its injured friend. One of the monkeys in the video fell unconscious after experiencing electric shock while walking on the high-tension wires in Kanpur’s railway station. The other monkey comes to the rescue.
The conscious monkey licks, bites, hits and puts the unconscious monkey into the stagnant water at the railway track. After 20 minutes of tireless effort, the ‘hero’ monkey brings its friend back to consciousness.
See also here.
These monkeys were rhesus macaques.
This video says about itself:
25 November 2014
Hello! We are from Taiwan. My daughter and I were very lucky to see an upside-down tortoise, but it’s luckier to see his friend trying to help him turn back in Taipei Zoo.
Today (25, November) is the field trip day of my daughter’s school and I also went to Taipei Zoo with her. We were all very lucky to see such kind of scene – one tortoise saves the other one’s life! Also, it’s a great opportunity to give my daughter a lesson – Helping others is the origin of happiness.
Translated from NOS TV in the Netherlands:
Wednesday, December 3, 2014, 20:14
The shell was already found a hundred years ago in Java. Now it discloses a mystery: a special inscription by a hominid 400,000 years old.
It is a thin zigzag pattern, engraved by an individual of Homo erectus, the predecessor of modern man. For seven years scientists worked on the study. The prestigious scientific journal Nature publishes it as a new insight into the evolution of human behaviour.
The shell was part of a very extensive discovery, made by the Dutch scientist Eugène Dubois. At the beginning of the twentieth century he discovered much valuable prehistoric material above the Javanese village Trinil. Per ship this was transported to the Netherlands.
Neatly documented were also the shells of freshwater mussels in a cardboard box in the institute Naturalis. Seven years ago it was opened by biologist and archaeologist José Joorens. She showed the shell to her Australian colleague Steven Munro. He made pictures of it. At home in Canberra he did his fascinating discovery. He immediately sent an e-mail to Joorens. It was the beginning of exciting research.
Joorens explains: “Munro saw a pattern of a kind of scratching on the shell. He was really surprised. Normally something like that should not be present in a shell…” In Leiden Joorens along with fellow researcher Frank Wesselingh needed a lot of time for further investigation. They had to consider all other possible causes of the scratches. Eventually they could draw no other conclusion anymore about this one shell.
“There are many things that may scratch,” said Wesselingh. “At first we did not believe ourselves what we saw. We considered all possibilities. And we can only conclude that this must have been done by a hominid.”
Until now only an engraving by Homo sapiens was known of 100,000 years old. It was found in South Africa. After the new discovery a drawing in color was made of a shaggy man who proudly displays the shell with a zigzag pattern. It is unclear what he meant. The researchers have carefully avoided to describe it as an early form of art.
“We can not look inside the head of Homo erectus,” said Joorens. “We do know that it must have taken considerable effort to make such a nice pattern. We have tried to imitate it and noticed that you have to really pay much attention to it to get it so neatly. It was absolutely a skilled individual.”
“Trinil was here”
Simply it might be a message like ‘Trinil was here’, in the handwriting of someone who wanted to leave something for posterity. “A matter of pride: to show that you possess something beautiful, as you now show an iPhone,” said Wesselingh. “That shell used to be quite dark. If you scratched it would show beautiful white luminous lines. The picture on the reconstruction is more beautiful than it is now, but what it means we do not know.”
The discovery gives rise to an adjustment of knowledge and ideas about the evolution of man. “It does not show that [our species] is earlier than we thought, but that we had predecessors who also had certain skills. It also says something about ourselves, that we tend to overestimate ourselves as modern man and underestimate others.”
See also here.
Homo erectus engraving could re-write human history, and might show art began 400,000 years earlier than we knew: here.
A recent article in the scientific journal Nature reports on the discovery of what appears to be a clamshell bearing intentionally produced geometric engravings dating to approximately half a million years ago (radiometrically dated to between 430,000 and 540,000 years before the present). If confirmed, this would be the oldest symbolic representation by human ancestors yet discovered, documenting an early stage in the development of modern human cognition: here.
This video is called African Animals Getting Drunk From Ripe Marula Fruit.
By Bob Yirka today:
19 hours ago
(Phys.org)—A team of researchers in the U.S. has found evidence to support the notion that our pre-human ancestors were able to metabolize ethanol long before our later ancestors learned to take advantage of fermentation—to create alcoholic beverages. In their paper published in Proceedings of the National Academy of Sciences, the team describes how they genetically sequenced proteins from modern primates and used what they found to work backwards to discover just how long ago our ancestors have been able to metabolize ethanol.
Humans have been consuming beverages that make them tipsy, drunk and/or sick for a very long time, of that there is little doubt. But why do we have the ability to metabolize ethanol in the first place? That’s what the team set out to answer. They began by sequencing an enzyme called ADH4—it’s what’s responsible for allowing us to metabolize ethanol. Other primates have it as well, but not all metabolize ethanol as well as we do. By sequencing ADH4 found in a 28 mammal species including 17 that were primates, the team was able to create a family tree of sorts based on ethanol metabolizing ability. The team then tested those sequences for their metabolizing ability by synthesizing nine kinds of the ADH4 enzyme. Doing so showed the researchers that most early primates had very little ability to metabolize ethanol for most of their early history.
Then, about 10 million years ago, some of the ancestors of modern humans suddenly were able to do a much better job of it, while others that diverged and led to apes such as orangutans, did not. This discovery led the team to wonder what might have occurred to cause this to come about. They note that other evidence has shown that around this same time, the planet cooled slightly, making life a little more difficult for our tree dwelling ancestors. They suggest they began climbing down out of the trees to eat the fruit that fell, which gave them a food advantage and a reason for developing the ability to metabolize ethanol—otherwise they would have become too drunk from eating the fermenting fruit to defend themselves or live otherwise normal lives. If true, the theory would also offer a major clue as to why our ancestors became terrestrial.
More information: Hominids adapted to metabolize ethanol long before human-directed fermentation, PNAS, Matthew A. Carrigan, DOI: 10.1073/pnas.1404167111
Paleogenetics is an emerging field that resurrects ancestral proteins from now-extinct organisms to test, in the laboratory, models of protein function based on natural history and Darwinian evolution. Here, we resurrect digestive alcohol dehydrogenases (ADH4) from our primate ancestors to explore the history of primate–ethanol interactions. The evolving catalytic properties of these resurrected enzymes show that our ape ancestors gained a digestive dehydrogenase enzyme capable of metabolizing ethanol near the time that they began using the forest floor, about 10 million y ago. The ADH4 enzyme in our more ancient and arboreal ancestors did not efficiently oxidize ethanol. This change suggests that exposure to dietary sources of ethanol increased in hominids during the early stages of our adaptation to a terrestrial lifestyle. Because fruit collected from the forest floor is expected to contain higher concentrations of fermenting yeast and ethanol than similar fruits hanging on trees, this transition may also be the first time our ancestors were exposed to (and adapted to) substantial amounts of dietary ethanol.
From Wildlife Extra:
Wild mouse lemurs live six times longer than similar-sized mammals
A new study has found that brown mouse lemurs in the wild can live to be up to at least eight years old, which is twice as long as other mammals of a similar size. They were also found to show signs of aging slower than captive grey mouse lemurs, which often display behavioural and neurological degeneration by the age of four, as well as developing grey hair and cataracts.
“It’s surprising that these tiny, mouse-sized primates, living in a jungle full of predators that probably consider them a bite-sized snack, can live so long. And we found individuals up to eight years of age in the wild with no physical symptoms of senescence like some captive mouse lemurs start getting by the age of four,” commented biologist Sarah Zohdy, post-doctoral fellow in Emory’s Department of Environmental Sciences and Rollins School of Public Health. Zohdy, who conducted the research while at the University of Helsinki, led the study on the brown mouse lemurs in Madagascar. She notes that it is likely factors such as starvation, predation, disease may decrease the observed rate of degeneration (known as senescence) in the wild, but evidence suggests that captivity can adversely affect mental and physical function.
“Comparing longevity data of captive and wild mouse lemurs may help us understand how the physiological and behavioural demands of different environments affect the aging process in other primates, including humans,” says Zohdy.
The study, which took place in Madagascar’s Ranomafana National Park, analysed a total of 420 dental impressions taken from 189 unique individuals between 2003 and 2010. 270 age estimates were calculated during the course of study, based on the wear rates of the mammals’ teeth.
“We found that wild brown mouse lemurs can live at least eight years. In the population that we studied, 16 per cent lived beyond four years of age,” Zohdy explains. “And we found no physical signs of senescence, such as greying hair or cataracts, in any wild individual.”
Hormone analysis of fecal samples from the mouse lemurs was also undertaken, and results revealed that there was no difference in testosterone levels between males and females. Ordinarily in most vertebrates, males tend to die first, so this is an unusual finding. Zohdy explains, “While elevated male testosterone levels have been implicated in shorter lifespans in several species, this is one of the first studies to show equivalent testosterone levels accompanying equivalent lifespans.”
Mouse lemurs are endemic to Madagascar and are the world’s smallest primate[s]. Although captive grey mouse lemurs can live beyond the age of 12, it is still not known what causes them to show earlier signs of senescence.
It is also not known why brown mouse lemurs in the wild have a much greater longevity than other animals of the same size. Zohdy suggests that the fact that wild mouse lemurs hibernate for half of the year could possibly boost their life span, but further research is needed to explain the findings.
“Our results do not provide information about wild brown mouse lemurs that can be directly compared to senescence in captive grey mouse lemurs,” she says. “Further research, using identical measures of senescence, will help to reveal whether patterns of physiological senescence occur consistently across the genus and in both captive and wild conditions.”
This video says about itself:
29 October 2014
Emory University biologist Sarah Zohdy studies mouse lemurs, the world’s smallest primates, in Madagascar’s Ranomafana National Park. The video shows a pregnant brown mouse lemur at night. “I saw her leap and catch a moth out of mid-air,” Zohdy says. “She then stopped a moment in the trees to clean off her mouth, hands and face, which is what you see on this video.”
This BBC video is called How to Speak Chimpanzee.
From Wildlife Extra:
Chimps found to be adapting to human neighbours
Wild chimpanzees could be learning to coexist with their human neighbours a new study suggests. Expanding land use for agriculture and other activities are increasingly encroaching on wild chimpanzee habitat and there are signs the chimps are adjusting to these habitat changes.
Researchers from Muséum national d’histoire naturelle have used camera-traps to observe chimpanzee behaviour during incursions out of the forest into maize fields in Kibale National Park, Uganda. During the 20 days of the study, a total of 14 crop-raiding events were recorded by the activation of the video-trap.
The researchers observed large parties of eight chimpanzees which also included vulnerable individuals such as females with clinging infants. This is the first record of frequent and repeated activities at night, in the darkness. Habitat destruction may have prompted the chimpanzees to adjust their normal behaviour to include innovative behaviours exploiting open croplands at night.
The study concluded: ”Even though the chimpanzees’ home range has been seriously damaged and disturbed by both logging activities and significant human demographic pressure, chimpanzees have shown great behavioural flexibility including unexpected nocturnal behaviour, in order to take advantage of the proximity of domestic nutritive food.
“The new findings of chimpanzee nocturnal raids can aid to formulate recommendations to local farmers and Park authorities in addition to those already listed as “best practice guidelines” from IUCN in terms of human-wildlife conflicts.”
This 16 October 2014 German video is about the recent research about white-footed sportive lemurs.
From Wildlife Extra:
Lemurs get messages when they go to the toilet
Public toilets are often a place humans use to communicate thoughts to others, and it is a habit not just restricted to humans, new research has discovered.
Scientists from the German Primate Center (DPZ) have found that White-footed sportive lemurs in southern Madagascar also use communal toilets as places to air their thoughts, only instead of writing on the walls, they use scent-marks on latrine trees to communicate with each other and warn intruders that that there is a male that will defend his partner.
This is an important method of communicating for them because although White-footed Sportive Lemurs are nocturnal tree-dwellers that live together in families consisting of parents and their offspring, the individuals do not interact much.
But what they have in common are latrines that are located in the core of their territory, which the whole family uses, and so it is a very useful place to leave messages for each other and keep in contact.
“Scent marks transmit a variety of information such as sexual and individual identity and may function to signal an individual’s presence and identity to others,” says Iris Dröscher, from the German Primate Center. “Latrines therefore serve as information exchange centres of individual-specific information.”
Read a field guide to the Ring-tailed lLemurs of Madagascar HERE.