How new behaviors appear and spread among capuchin monkeys

Date: August 24, 2017

Source: University of California - Los Angeles

Summary:

Older, sociable capuchins are prone to inventing more new types of social behaviors, many of which seem to function either as tests of friendship or displays against enemies. Other behaviors the researchers observed involved games, new ways to interact with infants and novel forms of sexual interaction.

Continued

Monkey see, monkey do, depending on age, experience and efficiency

Capuchin monkeys learn best-payoff ways to open fruit from others

Date: June 8, 2017

Source: University of California - Davis

Wild capuchin monkeys readily learn skills from each other -- but that social learning is driven home by the payoff of learning a useful new skill. It's the first demonstration of "payoff bias" learning in a wild animal, and could inform whether and how animals can adapt to rapidly changing conditions, for example due to climate change or reintroduction of species from captive breeding.

"When animals learn, they can learn very quickly," said Brendan Barrett, a graduate student in animal behavior at the University of California, Davis, who led the study, published June 7 in the journal Proceedings of the Royal Society B. "What are the psychological mechanisms animals use to learn?"

Barrett worked with a population of capuchin monkeys in northwest Costa Rica that was part of a 27-year study by UCLA professor Susan Perry. Capuchins are interesting because they have sophisticated social behaviors, and the kin relationships and early developmental histories of these monkeys were known.

"They explore their world, harvesting food from it," Barrett said. That includes coming up with new ways to open and harvest hard-to-access fruits and seeds. Unusually for monkeys, capuchins will tolerate other monkeys watching them as they open fruit.

Among the possible hypotheses: Monkeys conform with the group majority; they follow what experienced animals do; they learn from parents or close relatives; or they learn from their own experience.

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Maternal social skills found to play a factor in infanticide in capuchin monkeys

February 7, 2017 by Bob Yirka 

 (Phys.org)—A team of researchers with members from Canada, Japan and the U.S. has found that social skills in capuchin monkey mothers plays a role in the survivability of her offspring. In their paper published in Proceedings of the National Academy of Sciences, the researchers describe their study of the monkeys in their native Costa Rica and behavioral traits they observed that might be translatable to humans. 

To learn more about capuchin behavior, the research team studied data collected over the years 2005 and 2011 by researchers studying the monkeys in their native Costa Rica. They found that adult females that are more sociable tended to have babies with higher survival rates than less social mothers during times of stability. But, they also found that the situation was reversed when the dominant male in the group was either threatened or replaced—offspring of more social mothers were more likely to become the victims of infanticide by the new leader. Interestingly, they also found that maternal sociability came out even in the end—the team found no evidence of differences in offspring survivability rates overall.

Capuchin monkeys are well known throughout the world as both companions (or organ-grinders) and care-givers for humans. Their small size and childlike demeanor are considered assets and because of that, they have often been used in television and movies. In the wild, they are very different, of course—they inhabit areas from as far north as Central America to as far south as Argentina. Their behavior in groups as large as 35 has been extensively studied due to their social nature, which in some ways mimics that seen in humans.

In this latest study, the researchers suggest sociability plays a factor in offspring survivability because of the physical location they both occupy within the group—generally in the social nucleus. During times of stability, living in the middle of the group can provide protection for offspring from predators. Unfortunately, it can also make them the first to be targeted when a new lead male is looking to mate with those females closest in proximity. It is thought that new males kill infants to relieve the mothers from responsibility for them, making them available for mating.

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Monkeys create stone tools forcing scientists to rethink human evolution

 Sarah Knapton, Science Editor

19 October 2016 • 6:00pm 

The path of human evolution may need to be rewritten after archaeologists discovered that monkeys also produce ‘tool-like flakes’ that were thought to be uniquely man-made.

In a discovery that calls into question decades of research, a band of wild bearded capuchin monkeys in Brazil were seen hammering rocks to extract minerals, causing large flakes to fly off.

Previously archaeologists believed the flakes were only made by humans through a process called ‘stone-knapping’ where a larger rock is hammered with another stone to produce sharp blade-like slivers which can be used for arrows, spears or knives.

It does throw a bit of a spanner in the works in our thinking on evolutionary behaviourDr Michael Haslam, University of Oxford

The flakes were thought to represent a turning point in human evolution because they demonstrated a level of planning, cognition and hand manipulation that could not be achieved by other animals.

But the new research suggests that flakes can be made without any such foresight. In fact they can simply be made by accident.

“The fact that we have discovered monkeys can produce the same result does throw a bit of a spanner in the works in our thinking on evolutionary behaviour and how we attribute such artefacts,” said Dr Michael Haslam, lead of the Primate Archaeology project at the University of Oxford.

“Our understanding of the new technologies adopted by our early ancestors helps shape our view of human evolution. The emergence of sharp-edged stone tools that were fashioned and hammered to create a cutting tool was a big part of that story.”

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