Friendship provides a host of benefits for all parties involved.
For guppies, however, friendship is more than just a pleasure; it's a lifesaver.
A new study of Trinidadian guppies conducted by researchers from the University of Exeter, the University of York, and the University of the West Indies, St. Augustine found that the threat of predation motivated the fish to form stronger, more stable social bonds.
Interestingly, the groups of guppies tended to include fewer members, which suggests that smaller social groups are more conducive to stronger social bonds than large groups are.
Previous research on guppies has shown that individual fish recognize other individuals and develop social relationships, but this study has produced the first experimental evidence that predator threat affects the nature and strength of intraspecies social bonds.
"This research is important in our efforts to understand why social bonds and friendships form...The effects of dangerous environments on social bonds are also known in humans, such as between soldiers who form strong and long-lasting bonds during active duty in war zones," said the study's first author Dr. Robert Heathcote of the University of Exeter's Centre for Research in Animal Behaviour.
One of the hallmarks of guppy behavior is their tendency to leave and join new shoals with great frequency. Researchers observed social bonds among the fish by keeping track of the frequency with which the same fish swam together.
In the study, the guppies were kept in pools. Researchers exposed some of the fish to model predators. They found that when the guppies were aware of a possible predator in the area, they developed stronger social ties. This tendency was particularly noticeable among the largest and bravest individuals - those most at risk of predation.
While many species of animals protect themselves from predators by forming large groups, guppies went the opposite way. They formed smaller groups in order to protect themselves.
"We suggest this may reflect a conflict between the benefits of forming larger groups and those of forming stronger relationships...The maintenance of social relationships often requires individual recognition, which can be cognitively demanding when it involves large numbers," said study co-author Dr. Safi Darden.
The findings of this study contribute to the growing body of evidence suggesting that "friendships" are observable and serve an important purpose in the lives of many vertebrate species.
Another co-author of the study, Professor Darren Croft, believes that this study suggests that the threat of predation might have had a profound effect on the evolution of social relationships, and that further research should explore this possibility as it relates to different species.
The study was published in the journal Scientific Reports and you can check it out here.
What do you think? Let us know in the comments section!
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