A new study claims a sedentary lifestyle could be a prime way for a species to avoid extinction. Before you go canceling your gym membership, you have to ask yourself one vital question: Are you a mollusk? If the answer is no, you might want to keep pumping iron. Scientists from the University of Kansas analyzed mollusk extinctions over millions of years, finding the laziest species had the lowest chance of extinction.
The team led by postdoctoral researcher Luke Strotz used mollusks for this analysis for several reasons. For one, there are a lot of mollusks in the fossil record, particularly in the Western Atlantic. You can also assess the metabolic aspects of a mollusk from fossils. This allowed the team to analyze 299 different species of extinct and living mollusks across more than 5 million years from the mid-Pliocene to the present.
Overall, extinct mollusks are more likely to have higher metabolic levels. That means they need more resources to flourish than a “low-energy” species. This isn’t universally true, though. The researchers noted that species with narrow ranges were most affected by high metabolic activity. A mollusk that lives only in a certain area and has high metabolic activity is potentially in trouble. Meanwhile, a species with high metabolic activity that occupies wide ranges of ocean is in better shape.
Interestingly, the overall metabolic rate of mollusk communities tends to remain consistent over time. Some animals might go extinct, but others rise up into their “metabolic niche.” The team expected metabolic activity in a region to fluctuate or trend downward as more vulnerable species died off.
This isn’t just an academic question — an understanding of which species are most vulnerable could be vital as climate change pushes global temperatures higher. We might even be able to mitigate the effects of warming oceans if we can pinpoint the organisms that are at risk because of a higher metabolic rate. Research has suggested that the climate will continue warming even if we drastically cut greenhouse gas emissions. This is information that we’ll need to have.
The next step for the team is to assess how much impact metabolic rates have on extinction for other types of animals. It’s at least plausible that other marine animals will exhibit similar patterns. Proving a similar correlation on land would be much more difficult, but the team will attempt to find out.