They say life is lonely at the top, and it seems this includes the top of the food chain. Male Orcas are vulnerable if they lack social support.
Whales and dolphins form societies that closely resemble our own, for example they can have social networks that are tighter for some members than others. For male killer whales in the Pacific's much-studied Southern Resident community, position in these networks can be a matter of life and death when times are hard. With numbers down to 76, times are hard indeed.
"Killer whales are highly cooperative, and males at the centre of a social group are likely to have better access to social information and food-sharing opportunities," said Dr Samuel Ellis, from the University of Exeter, in a statement.
The whales' primary food source is salmon, which has been greatly depleted by overfishing and lack of access to spawning grounds blocked by dams.
In Proceedings of the Royal Society B, Ellis and colleagues report on an analysis of 40 years of sightings that show which whales frequently swim in tight social networks, and which keep to themselves or have just a few friends. When food was scarce, those at the center of social networks survived – probably because they had access to information on where remaining food was.
There was no difference in survival rates for females irrespective of network strength. The authors attributed this to larger males needing more food, but perhaps the females are just better at locating food on their own.
Although many other studies have shown the importance of animal social networks, most are conducted on species that require group-living for protection against predators, unlike killer whales.
If we want to save endangered populations like these, understanding what allows some to survive while others die is helpful – although stopping overfishing could be a solution. There might even be implications for other animal species, including our own.
The loss of social connection – particularly among middle-aged men – has attracted a lot of concern among sociologists. It's been raised as a possible explanation for why life expectancy is declining among certain sections of the American population, something that is almost unprecedented other than in periods of war or disease.
There has even been debate over whether it's a coincidence that Donald Trump did best, both in the primaries and the general election, in areas that score badly on measures for social networking. We'll probably never know whether isolated male killer whales would be angry enough to vote to make the Pacific great again, but they still might teach us something about ourselves.
1