Picky dolphins are choosy about their friends

December 18, 2018, University of St Andrews

Dolphins are picky about who they are friends with and shun rival groups, new research has found.

However, an international team of researchers, led by the University of St Andrews, found that the groups still managed to cooperate by sharing the sea – taking turns to inhabit particular areas.

The study, published in Marine Biology, investigated the social network of dolphins in the northern Adriatic Sea. It showed that dolphins living in the Gulf of Trieste form distinct social groups, and some don't like each other.

It is widely known that dolphins usually live in groups, and in the case of the common bottlenose dolphin the composition of these groups changes often, with members often joining or leaving.

However, these groups are not random. Rather, it is individual dolphins preferring to spend time with other individuals who could be described as their "best friends".

The researchers, from the Morigenos Slovenian Marine Mammals Society and the Sea Mammal Research Unit (SMRU) at the University of St Andrews, studied the dolphins in the region for more than 16 years.

They found that the dolphin society in the Gulf of Trieste comprised three distinct groups: two large social groups with stable membership and long-lasting friendships, and a smaller third social group, nicknamed "freelancers", with much weaker bonds and no long-lasting friendships.

However, although the two large groups tended to avoid each other, they did manage to share particular areas of the sea, with each group using them at different times of the day. Such temporal partitioning based on time of day has not previously been documented in whales and dolphins, nor in other mammals.

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Chimpanzees modify grooming behavior when near higher ranking members

Date: June 21, 2017

Source: University of Kent

Research by Dr Nicholas Newton-Fisher from the University of Kent has found chimpanzees modify their interactions with other chimpanzees if higher ranking members of their community are nearby.

Dr Newton-Fisher, based in the School of Anthropology and Conservation (SAC) at Kent, and Stefano Kaburu, from the Department of Population Health and Reproduction, School of Veterinary Medicine, UC Davis, University of California and formerly of SAC, observed grooming interactions between members of a community of chimpanzees in the Budongo Forest Reserve in Western Uganda.

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Bats make social alliances that affect roosting behavior

Date:

June 17, 2014

Source:

Virginia Tech

Summary:

Depending on habitat availability, the endangered Indiana bat may be able to use its social connections to survive a certain amount of roost destruction, according to research. Indiana bats form maternity colonies in summer beneath the bark of live trees or standing dead trees known as snags. "Social dynamics are important to bat roosting behavior," said one investigator. "And now, looking at results of a study of roosting and foraging activity in a new light, we have evidence that Indiana bats make social contacts during foraging."

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Social Lemurs Have More 'Street Smarts,' Study Finds

Lemurs that come from big tribes and live in large groups exhibit more "social smarts" than those that live with only a few companions, finds a new study that suggests the size of a primate's social network could influence its social intelligence.

Researchers designed a series of experiments to test lemurs' social cognition. Essentially, the scientists were curious how lemurs process a situation — specifically, how they decide whether or not a human can see them — and then how they use that information in manipulative ways — in this case, to steal a piece of food if they think they are not being watched, said lead study author Evan MacLean, a senior researcher in the department of evolutionary anthropology at Duke University in Durham, N.C.

"There's an idea that animals that live in big groups develop important psychological abilities, because they have to figure out how to get their way in an environment where they can't always get their way," MacLean told LiveScience.

Continued

Vertebrates Share Brain Circuitry for Social Decisions

The basic decision-making circuitry underlying social behaviors such as fighting and mating is incredibly similar in all vertebrates, from fish to mammals, new research suggests. These networks may be 450 million years old, the researchers said.

This means that while the input (whether, for example, it is sight or smell that the animal uses to find its mate) and output (how it performs its courtship rituals) may be different, the process the brain goes through to decide to pursue a certain mate is the same in many different species of animals, the researchers said.

"How these animals make decisions about whether to fight and how much to escalate their aggression may be made at least in part on pretty similar mechanisms in different species," said study researcher Hans Hofmann, of the University of Texas at Austin.


"It does make sense when you think about it because if you think about the tasks that animals have to solve, whether it is dealing with the risk and challenges of reproductive or other kinds of opportunities, they are fairly similar across species," Hofmann told LiveScience.


Vertebrate brains
The researchers examined decades of research on genes known to be involved in these social behaviors in 88 species of vertebrates — including birds, reptiles, fish and mammals — and used slices of their brains to look at the genes' expression in 12 different brain regions associated with the social decision-making network.


They analyzed this huge data set to see how similar genes expressed in this network look across species. While species within a group –  say, reptiles – were expected to be similar, the researchers also found a large similarity between even far-ranging species, such as mammals and fish.


Because these networks are preserved so far back in the vertebrate lineage, they must have been there since the fish split from four-limbed animals 450 million years ago, Hofmann said.




http://www.livescience.com/20673-social-decision-making-brain-circuit.html