Bats prefer to rest with their closest pals rather than with bats they don't know very well, researchers have discovered.
They found that although bats change where they sleep every few days, they nearly always roost with the same bunch of bats, forming tight-knit social groups with exclusive membership.
'Bats build long-term companionships with other individuals, and these companions are members of exclusive social groups that can last for many years,' explains Tom August from the Centre for Ecology & Hydrology (CEH), who's studying the bats as part of his PhD at the University of Exeter.
'I was interested in fitting together disease and ecology, and wanted to know if the ecology of bats influences the diseases they carry,' he says.
Despite being cute-looking creatures, a very small number of UK bats carry rabies-like viruses. They can also be the source of emerging diseases. 'The SARS virus is thought to have originated from bats in China,' says August.
By getting a better understanding of how individual bats interact with each other, researchers are hoping to predict how diseases might spread, 'which may point to ways in which the risks to humans can be reduced.'
Bat numbers have dropped dramatically in recent years, because of loss of habitat. They like roosting in buildings and trees, and during the winter, tend to hibernate in caves. All bats in the UK are protected species.
Bat experts have long known that they often rest together: males roost on their own, or sometimes in small groups; while female bats establish so-called maternity colonies around June when many soon-to-be mothers come together to have their pups.
But this is the first time researchers have shown that bats form exclusive social groups – at least in the UK.
By revealing how bats stick together in distinct social groups, the research shows that conservation efforts should focus on whole areas used by groups, rather than just single roosts.
August and colleagues from CEH and the University of Exeter studied the hundreds of bats that live in Wytham Woods, just outside Oxford in the UK.
Around 200 Daubenton's and 200 Natterer's bats live in the woods, making use of some of the 1200 bird boxes which have been there for the last 40 or 50 years. Birds use them early in the season, but as soon as they leave, the bats move in.
Wytham Woods is owned by the University of Oxford and is probably the most heavily-studied woodland in the UK. Indeed all of the bats are fitted with tiny aluminium arm bands with unique numbers to make identifying them easier.
'The fact that bats change their roosts so frequently means this kind of study has been difficult up until now,' says August.
After taking meticulous notes of which bats associate with each other, August built up a 'spider-web' diagram to reveal the bats' social networks.
'Instead of a huge spider web, you get clusters, which clearly show how individual bats associate with each other,' August says. 'In this one wood, we found six or seven social groups.'
Groups appear to be made up of around 20 to 40 individuals. 'It could be that they're coming together to share information about where food is,' says August.
The study will be presented to delegates of the British Ecological Society's annual meeting in Sheffield today.
by Tamera Jones
http://planetearth.nerc.ac.uk/news/story.aspx?id=1062
Showing posts with label social behaviour. Show all posts
Showing posts with label social behaviour. Show all posts
Wednesday, September 14, 2011
Friday, May 6, 2011
Chimpanzees' 66 gestures revealed
Thursday, 5 May 2011
By Victoria Gill
Science and nature reporter, BBC News
Wild chimpanzees use at least 66 distinct gestures to communicate with each other, according to scientists.
A team of researchers from the University of St Andrews in Scotland filmed a group of the animals in order to decipher this "gestural repertoire".
The team then studied 120 hours of footage of the chimps interacting, looking for signs that the animals were intentionally signalling to each other.
The findings are published in the journal Animal Cognition.
Previous studies on captive chimps have suggested the animals have about 30 different gestures.
"So this [result] shows quite a large repertoire," lead researcher Dr Catherine Hobaiter told BBC News.
"We think people previously were only seeing fractions of this, because when you study the animals in captivity you don't see all their behaviour.
"You wouldn't see them hunting for monkeys, taking females away on 'courtships', or encountering neighbouring groups of chimpanzees."
Dr Hobaiter spent 266 days observing and filming a group of chimpanzees in Budongo Conservation Field Station, Uganda.
"I've spent two years studying these animals, so they know me," she said. "I follow them through the forest and they just ignore me completely and get on with their daily lives."
She and her colleague, Professor Richard Byrne, scrutinised the footage and categorised each distinct gesture.
They looked for clear signs that the animals were making deliberate movements that were intended to generate a response from another animal.
"We looked to see if the gesturer was looking at their audience," explained Professor Byrne.
"And we looked for persistence; if their action did not produce a result, they would repeat it."
The team is still studying the footage for the next stage of their project - to figure out what each gesture means.
For some of these gestures, the meaning seems obvious to us, perhaps because - as great apes- we make similar movements. A chimp will often beckon to another group member, or a youngster will hand shake at another juvenile to entice it to play.
Gesture dictionary
In one piece of footage captured by Dr Hobaiter, a mother reaches with her left arm towards her daughter.
"The mother wants to move away and is gesturing to request that her daughter 'climbs on' her," Dr Hobaiter explained.
"She could just grab her daughter, but she doesn't. She reaches and holds the gesture while waiting for a response."
When the youngster starts to approach, the mother repeats the gesture and adds a facial expression - a "bare-teeth grin", at which point the daughter climbs on and they move away.
"But actions often have effects that their maker did not intend," said Professor Byrne.
"So to understand the intended meaning, it's no good just discovering a gesture's typical effect. We have to look for what effect makes the signaller stop gesturing and appear satisfied and content with the outcome, to be sure that that was what they intended."
The results have provided clues about the origins of chimps' gestures, suggesting that they are a common system of communication across the species, rather than each movement being a learned custom or ritual within one social group.
In fact, by comparing these observations with those of gestures made by gorillas and orangutans, the researchers showed there was significant overlap in the signals used throughout the family of great apes.
Dr Hobaiter said: This supports our belief that the gestures that apes use (and maybe some human gestures too) are derived from ancient shared ancestry of all the great ape species alive today."
http://news.bbc.co.uk/earth/hi/earth_news/newsid_9475000/9475408.stm
By Victoria Gill
Science and nature reporter, BBC News
Wild chimpanzees use at least 66 distinct gestures to communicate with each other, according to scientists.
A team of researchers from the University of St Andrews in Scotland filmed a group of the animals in order to decipher this "gestural repertoire".
The team then studied 120 hours of footage of the chimps interacting, looking for signs that the animals were intentionally signalling to each other.
The findings are published in the journal Animal Cognition.
Previous studies on captive chimps have suggested the animals have about 30 different gestures.
"So this [result] shows quite a large repertoire," lead researcher Dr Catherine Hobaiter told BBC News.
"We think people previously were only seeing fractions of this, because when you study the animals in captivity you don't see all their behaviour.
"You wouldn't see them hunting for monkeys, taking females away on 'courtships', or encountering neighbouring groups of chimpanzees."
Dr Hobaiter spent 266 days observing and filming a group of chimpanzees in Budongo Conservation Field Station, Uganda.
"I've spent two years studying these animals, so they know me," she said. "I follow them through the forest and they just ignore me completely and get on with their daily lives."
She and her colleague, Professor Richard Byrne, scrutinised the footage and categorised each distinct gesture.
They looked for clear signs that the animals were making deliberate movements that were intended to generate a response from another animal.
"We looked to see if the gesturer was looking at their audience," explained Professor Byrne.
"And we looked for persistence; if their action did not produce a result, they would repeat it."
The team is still studying the footage for the next stage of their project - to figure out what each gesture means.
For some of these gestures, the meaning seems obvious to us, perhaps because - as great apes- we make similar movements. A chimp will often beckon to another group member, or a youngster will hand shake at another juvenile to entice it to play.
Gesture dictionary
In one piece of footage captured by Dr Hobaiter, a mother reaches with her left arm towards her daughter.
"The mother wants to move away and is gesturing to request that her daughter 'climbs on' her," Dr Hobaiter explained.
"She could just grab her daughter, but she doesn't. She reaches and holds the gesture while waiting for a response."
When the youngster starts to approach, the mother repeats the gesture and adds a facial expression - a "bare-teeth grin", at which point the daughter climbs on and they move away.
"But actions often have effects that their maker did not intend," said Professor Byrne.
"So to understand the intended meaning, it's no good just discovering a gesture's typical effect. We have to look for what effect makes the signaller stop gesturing and appear satisfied and content with the outcome, to be sure that that was what they intended."
The results have provided clues about the origins of chimps' gestures, suggesting that they are a common system of communication across the species, rather than each movement being a learned custom or ritual within one social group.
In fact, by comparing these observations with those of gestures made by gorillas and orangutans, the researchers showed there was significant overlap in the signals used throughout the family of great apes.
Dr Hobaiter said: This supports our belief that the gestures that apes use (and maybe some human gestures too) are derived from ancient shared ancestry of all the great ape species alive today."
http://news.bbc.co.uk/earth/hi/earth_news/newsid_9475000/9475408.stm
Wednesday, December 8, 2010
Hormone makes meerkats more cooperative
Dosing meerkats with the hormone oxytocin makes them spend more time and energy helping others in their group, according to a new study.
And it doesn't just affect one or two of meerkats' wide range of cooperative or 'pro-social' behaviours - it boosts a broad spectrum.
This finding may hold the answer to why social animals don't just help out with tasks they will directly benefit from, like digging burrows - they also do things for the good of the group that actually cost them as individuals, like giving food they've caught to other group members' young.
'All the co-operative behaviours seem to be controlled at a high level by the same pathway,' says Dr Joah Madden of the University of Exeter, lead author of the paper, published in Proceedings of the Royal Society B. 'One of the big questions in animal behaviour has been why individuals behave cooperatively. Until now, studies have typically looked at just one behaviour and tried to find explanations for it in isolation, rather than looking at altruistic behaviour as a whole syndrome.'
Madden and co-author Professor Tim Clutton-Brock of the University of Cambridge gave intramuscular injections of either oxytocin or a control saline solution to 36 wild meerkats from four groups living in South Africa's Kuruman River Reserve. They then counted how often they behaved cooperatively over the next half hour.
Animals that had been given oxytocin showed significantly higher levels of cooperative behaviours – like helping dig burrows, guarding the group from predators and caring for young – than when they had received a placebo.
The effects on all the cooperative actions were noticeable. Individuals exposed to oxytocin showed around a 50 per cent increase in the amount of their food they gave to young. And they were about half as likely to behave aggressively.
Digging or guarding benefits all the animals in a group, but giving away food to pups may reduce the individual's own nutritional state, while providing the feeder with limited direct benefits.
On the face of it, it's easier to understand why animals would engage in the first kind of altruistic activity than the second. But this study suggests there's a single mechanism controlling both kinds of altruistic behaviour. Because there is a whole suite of these cooperative activities, all moderated by a pathway involving oxytocin, the meerkats can't selectively engage in one or two of them but ignore others.
'Individuals could be caught in a bind in which they behave in ways that are harmful to them because these behaviours are part of the same system as other behaviours that are beneficial,' Madden suggests. 'Of course you would expect altruistic behaviour to be beneficial, or the animals wouldn't do it,' he adds. If the net result is generally beneficial, individuals might find themselves behaving in ways that harm their own interests.
'Over time you would expect that natural selection will weed out specific behaviours that are costly for the individual and decouple them from those behaviours that provide benefits, but this can take a long time,' Madden adds.
Oxytocin acts as a neurotransmitter in mammals' brains, and is released in largest quantities during childbirth. It's already been shown to cause altruistic behaviour in voles, and studies have even shown that it can increase pro-social traits like trust and reliability in humans.
Madden says it would now be interesting to investigate the effects of oxytocin in a wider range of species, including both social and non-cooperative animals.
The research was funded directly by a grant from the Biotechnology and Biological Sciences Research Council, but built on work supported by earlier funding from the Natural Environment Research Council. A vet was present throughout the experiments to make sure the meerkats weren't harmed.
Tom Marshall
http://planetearth.nerc.ac.uk/news/story.aspx?id=889
And it doesn't just affect one or two of meerkats' wide range of cooperative or 'pro-social' behaviours - it boosts a broad spectrum.
This finding may hold the answer to why social animals don't just help out with tasks they will directly benefit from, like digging burrows - they also do things for the good of the group that actually cost them as individuals, like giving food they've caught to other group members' young.
'All the co-operative behaviours seem to be controlled at a high level by the same pathway,' says Dr Joah Madden of the University of Exeter, lead author of the paper, published in Proceedings of the Royal Society B. 'One of the big questions in animal behaviour has been why individuals behave cooperatively. Until now, studies have typically looked at just one behaviour and tried to find explanations for it in isolation, rather than looking at altruistic behaviour as a whole syndrome.'
Madden and co-author Professor Tim Clutton-Brock of the University of Cambridge gave intramuscular injections of either oxytocin or a control saline solution to 36 wild meerkats from four groups living in South Africa's Kuruman River Reserve. They then counted how often they behaved cooperatively over the next half hour.
Animals that had been given oxytocin showed significantly higher levels of cooperative behaviours – like helping dig burrows, guarding the group from predators and caring for young – than when they had received a placebo.
The effects on all the cooperative actions were noticeable. Individuals exposed to oxytocin showed around a 50 per cent increase in the amount of their food they gave to young. And they were about half as likely to behave aggressively.
Digging or guarding benefits all the animals in a group, but giving away food to pups may reduce the individual's own nutritional state, while providing the feeder with limited direct benefits.
On the face of it, it's easier to understand why animals would engage in the first kind of altruistic activity than the second. But this study suggests there's a single mechanism controlling both kinds of altruistic behaviour. Because there is a whole suite of these cooperative activities, all moderated by a pathway involving oxytocin, the meerkats can't selectively engage in one or two of them but ignore others.
'Individuals could be caught in a bind in which they behave in ways that are harmful to them because these behaviours are part of the same system as other behaviours that are beneficial,' Madden suggests. 'Of course you would expect altruistic behaviour to be beneficial, or the animals wouldn't do it,' he adds. If the net result is generally beneficial, individuals might find themselves behaving in ways that harm their own interests.
'Over time you would expect that natural selection will weed out specific behaviours that are costly for the individual and decouple them from those behaviours that provide benefits, but this can take a long time,' Madden adds.
Oxytocin acts as a neurotransmitter in mammals' brains, and is released in largest quantities during childbirth. It's already been shown to cause altruistic behaviour in voles, and studies have even shown that it can increase pro-social traits like trust and reliability in humans.
Madden says it would now be interesting to investigate the effects of oxytocin in a wider range of species, including both social and non-cooperative animals.
The research was funded directly by a grant from the Biotechnology and Biological Sciences Research Council, but built on work supported by earlier funding from the Natural Environment Research Council. A vet was present throughout the experiments to make sure the meerkats weren't harmed.
Tom Marshall
http://planetearth.nerc.ac.uk/news/story.aspx?id=889
Hormone makes meerkats more cooperative
Dosing meerkats with the hormone oxytocin makes them spend more time and energy helping others in their group, according to a new study.
And it doesn't just affect one or two of meerkats' wide range of cooperative or 'pro-social' behaviours - it boosts a broad spectrum.
This finding may hold the answer to why social animals don't just help out with tasks they will directly benefit from, like digging burrows - they also do things for the good of the group that actually cost them as individuals, like giving food they've caught to other group members' young.
'All the co-operative behaviours seem to be controlled at a high level by the same pathway,' says Dr Joah Madden of the University of Exeter, lead author of the paper, published in Proceedings of the Royal Society B. 'One of the big questions in animal behaviour has been why individuals behave cooperatively. Until now, studies have typically looked at just one behaviour and tried to find explanations for it in isolation, rather than looking at altruistic behaviour as a whole syndrome.'
Madden and co-author Professor Tim Clutton-Brock of the University of Cambridge gave intramuscular injections of either oxytocin or a control saline solution to 36 wild meerkats from four groups living in South Africa's Kuruman River Reserve. They then counted how often they behaved cooperatively over the next half hour.
Animals that had been given oxytocin showed significantly higher levels of cooperative behaviours – like helping dig burrows, guarding the group from predators and caring for young – than when they had received a placebo.
The effects on all the cooperative actions were noticeable. Individuals exposed to oxytocin showed around a 50 per cent increase in the amount of their food they gave to young. And they were about half as likely to behave aggressively.
Digging or guarding benefits all the animals in a group, but giving away food to pups may reduce the individual's own nutritional state, while providing the feeder with limited direct benefits.
On the face of it, it's easier to understand why animals would engage in the first kind of altruistic activity than the second. But this study suggests there's a single mechanism controlling both kinds of altruistic behaviour. Because there is a whole suite of these cooperative activities, all moderated by a pathway involving oxytocin, the meerkats can't selectively engage in one or two of them but ignore others.
'Individuals could be caught in a bind in which they behave in ways that are harmful to them because these behaviours are part of the same system as other behaviours that are beneficial,' Madden suggests. 'Of course you would expect altruistic behaviour to be beneficial, or the animals wouldn't do it,' he adds. If the net result is generally beneficial, individuals might find themselves behaving in ways that harm their own interests.
'Over time you would expect that natural selection will weed out specific behaviours that are costly for the individual and decouple them from those behaviours that provide benefits, but this can take a long time,' Madden adds.
Oxytocin acts as a neurotransmitter in mammals' brains, and is released in largest quantities during childbirth. It's already been shown to cause altruistic behaviour in voles, and studies have even shown that it can increase pro-social traits like trust and reliability in humans.
Madden says it would now be interesting to investigate the effects of oxytocin in a wider range of species, including both social and non-cooperative animals.
The research was funded directly by a grant from the Biotechnology and Biological Sciences Research Council, but built on work supported by earlier funding from the Natural Environment Research Council. A vet was present throughout the experiments to make sure the meerkats weren't harmed.
Tom Marshall
http://planetearth.nerc.ac.uk/news/story.aspx?id=889
And it doesn't just affect one or two of meerkats' wide range of cooperative or 'pro-social' behaviours - it boosts a broad spectrum.
This finding may hold the answer to why social animals don't just help out with tasks they will directly benefit from, like digging burrows - they also do things for the good of the group that actually cost them as individuals, like giving food they've caught to other group members' young.
'All the co-operative behaviours seem to be controlled at a high level by the same pathway,' says Dr Joah Madden of the University of Exeter, lead author of the paper, published in Proceedings of the Royal Society B. 'One of the big questions in animal behaviour has been why individuals behave cooperatively. Until now, studies have typically looked at just one behaviour and tried to find explanations for it in isolation, rather than looking at altruistic behaviour as a whole syndrome.'
Madden and co-author Professor Tim Clutton-Brock of the University of Cambridge gave intramuscular injections of either oxytocin or a control saline solution to 36 wild meerkats from four groups living in South Africa's Kuruman River Reserve. They then counted how often they behaved cooperatively over the next half hour.
Animals that had been given oxytocin showed significantly higher levels of cooperative behaviours – like helping dig burrows, guarding the group from predators and caring for young – than when they had received a placebo.
The effects on all the cooperative actions were noticeable. Individuals exposed to oxytocin showed around a 50 per cent increase in the amount of their food they gave to young. And they were about half as likely to behave aggressively.
Digging or guarding benefits all the animals in a group, but giving away food to pups may reduce the individual's own nutritional state, while providing the feeder with limited direct benefits.
On the face of it, it's easier to understand why animals would engage in the first kind of altruistic activity than the second. But this study suggests there's a single mechanism controlling both kinds of altruistic behaviour. Because there is a whole suite of these cooperative activities, all moderated by a pathway involving oxytocin, the meerkats can't selectively engage in one or two of them but ignore others.
'Individuals could be caught in a bind in which they behave in ways that are harmful to them because these behaviours are part of the same system as other behaviours that are beneficial,' Madden suggests. 'Of course you would expect altruistic behaviour to be beneficial, or the animals wouldn't do it,' he adds. If the net result is generally beneficial, individuals might find themselves behaving in ways that harm their own interests.
'Over time you would expect that natural selection will weed out specific behaviours that are costly for the individual and decouple them from those behaviours that provide benefits, but this can take a long time,' Madden adds.
Oxytocin acts as a neurotransmitter in mammals' brains, and is released in largest quantities during childbirth. It's already been shown to cause altruistic behaviour in voles, and studies have even shown that it can increase pro-social traits like trust and reliability in humans.
Madden says it would now be interesting to investigate the effects of oxytocin in a wider range of species, including both social and non-cooperative animals.
The research was funded directly by a grant from the Biotechnology and Biological Sciences Research Council, but built on work supported by earlier funding from the Natural Environment Research Council. A vet was present throughout the experiments to make sure the meerkats weren't harmed.
Tom Marshall
http://planetearth.nerc.ac.uk/news/story.aspx?id=889
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