'Survival of the Laziest' Gains Support as a Strong Evolutionary Strategy

Good news, fellow couch-dwellers! Our laziness has scientific support. Well, kind of — you have to be an oyster to claim this one. While humans need to exercise to maintain physical and mental health, for some organisms, it’s actually better in the long run to expend less energy.

In a paper published Tuesday in the journal Proceedings of the Royal Society B, a team of scientists at Oxford University and the University of Kansas shows evidence that over a period of 5.33 million years, prehistoric mollusks in the Western Atlantic Ocean that required less energy to survive were less likely to go extinct. While laziness wouldn’t likely be a conscious choice for those sea creatures (bivalves like clams and oysters, and gastropods like snails and conchs), scientifically, it helped their chances for a long life.

Scientists calculated the basal metabolic rate of the organisms from fossil remains and confirmed that a lower basal metabolic rate is associated with longer lifespans in individual organisms. This was expected, but they also made the surprising discovery that this same relationship was true for populations as a whole.

“There was no reason to expect that effects that apply to individuals also apply to species. So there wasn’t necessarily a reason to expect that the extinction of a species should be related to metabolic rate in the same way as the lifespan of an individual is,” Luke Strotz, Ph.D., a postdoctoral researcher in paleontology at the University of Kansas and the first author on the paper, tells Inverse.

To conduct this research, the study’s authors calculated 299 species’ basal metabolic rates by measuring the size range of specimens, both extinct and still living, from museum collections. Then they used the Hadley global climate model to obtain estimates of what the ocean temperature had been when these organisms lived in the ocean. With these two measurements, they came up with a reasonable estimate of how much energy the organisms needed to stay alive. The result? The organisms with a lower basal metabolic rate that needed less energy to survive were more likely to live longer than organisms that required more energy. This relationship was true not just for the individuals but for entire species.

While metabolic rate correlates strongly with extinction, it’s not the only driver of extinction, Strotz says.

“Metabolic rate is linked to a constellation of characteristics including growth rate, time to maturity, maximum life span and maximum population size. It seems likely that the nature of any or all of these traits play a role in how vulnerable a species is to extinction,” he says. “Extinction is complex and no one factor is responsible for all extinctions.”

Strotz tells Inverse that he headed into the study prepared to publish a negative result, and he had planned to discuss that negative result through the lens of hierarchy theory, a principle that states that a system is more than just the sum of its parts. In this case, though populations are complex, they exhibited the same relationship between metabolism and survival as the individuals in the population.

“Getting a positive result showing higher metabolic rates correlated with a higher likelihood of extinction was therefore somewhat unexpected,” Strotz says.

But before you tell yourself that you can live like a mollusk, expending as little energy as possible in an effort to live longer, be warned: That’s not how evolution works. Sorry!

The study’s authors calculated an average metabolic rate for organisms, meaning the average amount of energy it took for the organisms to survive, not how much they chose to expend. Basal metabolic rate isn’t a lifestyle choice like the decision to exercise, but a biological and evolutionary trait like how tall you are.

“You can’t just decide to be lazy as an individual and expect to live longer,” says Strotz. It’s too bad, especially for lazy humans who would rather sit around eating steak all day.