The unemployed couch potato kidult that lived at home at the age of 30 could, according to a new theory, represent the next phase in human evolution.
A study has discovered a previously overlooked law of natural selection, based on "surviving the slacker".
It suggests that laziness can be a good strategy for the survival of individuals, species and even entire groups of species.
And although the study was based on low molluscs living on the bottom of the Atlantic, the authors think they may have found a general principle that could apply to higher animals – including vertebrates.
The scientists conducted an extensive study of the energy needs of 299 species of extinct and live bivalves and gastropods spread over a period of five million years.
Those who had managed to escape extinction and survived to this day were mostly "low-maintenance" species with minimal energy needs.
Molluscs that had gone down and disappeared from the dinosaurs had higher metabolic values than their still-growing cousins.
The American ecologist Professor Bruce Lieberman, who was co-leader of the University of Kansas team, said: "Perhaps the best evolutionary strategy for animals in the long run is lassitudinous and slow.
"The lower the metabolism, the greater the chance that the species you belong to will survive." Instead of "survival of the fittest" is perhaps a better metaphor for the history of life. of the lazy & # 39; or at least, & # 39; survive from the slow & # 39 ;. "
The findings, reported in the journal Proceedings of the Royal Society B, can have important implications for predicting the fate of species that are affected by climate change, according to the scientists.
Dr. Luke Strotz, also from the University of Kansas, said: "In a sense, we are looking at a potential predictor of the extinction probability.
"At the level of the species, the metabolic rate is not the only and the end of extinction – there are many factors involved, but these results say that the metabolic rate of an organism is part of the likelihood of extinction.
"With a higher metabolic rate, a species will probably die more extensively, so it is another tool in the toolbox that will help us understand the mechanisms that cause extinction and help us better determine the likelihood of extinction."
Energy consumption had a greater impact on species that were closely distributed, according to the researchers.
Species with a narrow range reached much more often if they had a high metabolism.
Molluscs were used for the study because of the huge amount of available data on live and extinct bivalve and gastropod species.
The team now plans follow-up to see if the "survival of the most lazy" natural selection applies to other types of animals.
Dr. Strotz added: "There is a question about whether this is just a mollusc phenomenon.
"There is some justification, given the size of this dataset, and the length of time it covers, that it can be generalized, but you have to look – can it apply to vertebrates? Can it apply to the land? & # 39;