Male bottlenose dolphins that form friendships age more slowly than loners, new research shows.
Dolphins are social creatures that, like all of us, get old.
Signs of ageing in dolphins include less energy, changes to skin, slower movement, and fading eyesight.
But dolphins have access to a powerful anti-ageing serum.
UNSW scientists have analysed dolphin cell samples and found male bottlenose dolphins with strong social bonds age more slowly than their more solitary peers.
"Social connections are so important for health that they slow down ageing at the cellular level," says study lead author Dr Livia Gerber, who conducted the research at UNSW and now works at CSIRO.
"We knew social bonds helped animals live longer, but this is the first time we have shown that they affect the ageing process."
Male dolphin friendships can last decades, with relationships looking much like ours, which is why Dr Gerber decided to focus on males instead of females.
"Female dolphins have a different pattern of social bonding that is influenced by having offspring of similar age," she says, adding that as a result their relationships are a lot more fluid.
Males, however, hang out and play together, surf waves for fun, rest side by side, and form long-lasting, deep social bonds.
"It reminds me of two kindergarten buddies who stay together through school, careers, and retirement and share all of life's joys and challenges," says Dr Gerber.
"Having friends means you hunt together, watch each other's backs, and share the load."
Compare that to the alternative, a lonely life in the ocean where the dolphin would have to hunt for itself, compete for mates without backup, and face sharks and other predators alone.
All of which contribute to a much more stressful existence, which much like in humans, Dr Gerber says is a key driver of ageing in dolphins.
"Having friends gives dolphins a support network that makes life's challenges much more manageable."
The researchers built up a picture of a dolphin population in Shark Bay, Western Australia, analysing social connections based on years' worth of observations.
Like humans, male dolphins that have close social bonds spend a lot of time together, so whenever the team goes out on the boat to observe the dolphins, they record which ones are next to each other.
According to Dr Gerber, dolphins with close social bonds are almost always seen close together.
Most research into the effects of social bonds on ageing has focussed on chronological age and lifespan-that is to say, how old an animal is, measured from its date of birth.
For this study, however, researchers used DNA markers to design an "epigenetic clock" to estimate the biological age of an individual, giving a better indicator of its overall health and ageing status.
In humans, age estimates derived from epigenetic clocks have been used to determine how much various factors like pollution, depression, and positive or negative social bonds impact biological age.
"Increasingly, we are also using epigenetic data to advance our knowledge of the ecology of wild populations, including the epigenetic clocks used here," says co-author Professor Lee Rollins from the UNSW School of Biological, Earth & Environmental Sciences .
The researchers studied 50 skin tissue samples from a 38 bottlenose dolphins in Shark Bay, and found that individuals with better, tighter social bonds aged slower, and therefore likely had easier lives.
"The health benefits of friendship are not unique to humans, but are a fundamental biological principle across social mammals," says Dr Gerber.
"This research should change how we think about animal welfare and remind us that social needs are biological needs."
While this is the first time research has shown a reduction in biological age due to strong social bonds, Dr Gerber wants to see more research into friendship and ageing in elephants, primates, wolves and any other animal that forms lasting social bonds.
"I am predicting that we will find that friendship is a natural anti-aging secret across social animals."
And the researchers say this work underscores that for humans, investing time in meaningful relationships should be as much a priority as eating well and exercising.
The research has been published in the journal Nature Communications Biology .
