Male dolphins are healthier and live longer when they have a network of male friends. Find out how a new study revealed that this popularity also makes them more likely to find mates.
There’s a quote attributed to Charles Darwin that goes, “It is not the strongest of the species that survives, not the most intelligent that survives. It is the one that is the most adaptable to change.” Experts disagree about whether it’s a verbatim quote or more of a paraphrase, but anyway it came to mind this week.
When I was growing up, the conventional wisdom was that evolution favoured rugged indivudualists rather than agreeable conformists. The strong thrived while nice guys finished last.
Lately, scientists have been uncovering more and more evidence that friendly, agreeable, supportive individuals are more likely to pass on their genes than their more dominant counterparts. This is especially true of social species.
Group Cohesion More Important than Individual Success
When it comes to social animals like wolves, apes, or humans, the cohesion of the group is often more important for natural selection than individual success. Since evolution takes place at the species rather than the individual level, it’s the strength of the team and team players that prevails.
Last week, researchers led by the University of Zurich confirmed that the same principle applies to sea mammals. They were studying dolphin pods in Shark Bay, Western Australia.
They found that male dolphins’ reproductive success is a function of their social bonds with other males, and not their strength or age. The more integrated the males were within the dolphin community, the more offspring they generated.
Male Dolphins Form Complex Social Groups
The male dolphins living in Shark Bay form complex social groups involving long-term relationships with two or three other males. These relationships expand to form large, stable alliances within the pod.
Livia Gerber is a PhD candidate in the University of Zurich’s Evolutionary Genetics Group and the study’s lead author. Working with University of Zurich professor Michael Krutzen, she wanted to determine whether dolphin culture played a larger role than strength, experience, or status in reproductive success.
To work this out, the team reviewed 30 years worth of data on the behaviour of 85 male dolphins in Shark Bay. They compared this with genetic data to perform paternity analyses on a sample of 400 dolphins.
Well-Connected Males Sire the Most Descendants
The results show that well-connected males with strong social bonds to a large network of alliance members sire the most descendants. This was more important than stability within the smaller packs of two or three males.
Prior research had indicated that these popular males enjoyed better health and lived longer. That might explain why they’re more likely to pass on their genes, but Ms. Gerber thinks there’s another factor at work.
“Well-integrated males might be in a better position to harness the benefits of cooperation and access crucial resources such as food or mates. They may also be more resilient to partner loss compared to those with few, but closer partners.”
“We Talk About These Groups as Wingmen”
Professor Krutzen offered a familiar analogy. “We talk about these groups as wingmen because that’s definitely what they are.”
Hey went on to elaborate, “These guys know each other from when they are weaned off their mums and they stay in tight groups for years. It’s like in humans, where if you know you can really trust your buddy you are stronger together.”
Natural selection plays a central role in piecing together the New Story that explains where we came from and our ties to the larger web of Life. We know that cooperation among friends is very common among all mammals.
Cooperation Drives Paternity Success
Ms. Gerber’s insights shed light on how that cooperation drives paternity success. This isn’t something that scientists have looked into very carefully.
Some related research shows that social bonds among primates drive survival of the fittest. Even so, this is the first discovery of sea mammals showing the same kind of success.
Professor Krutzen concluded by saying, “Our study expands upon previous findings on land mammals and provides compelling evidence that such highly complex, multi-level social systems also developed independently in the ocean.”
We always have more to learn if we dare to know.
Popular Male Dolphins Produce More Offspring
Cooperative partner choice in multi-level male dolphin alliances
Origin of Life Before the Origin of Species
Agreeable People Are More Successful at Work
Friendly People Ensured Human Survival