Hundreds of millions of years ago, a massive die off in the ocean left fish notably smaller, which bodes well for the smaller fish currently swimming about.
Published in the journal Science, the new study detailed an extinction known as the Hangenberg event occurred some 359 million years ago and left the Earth's vertebrates a bit smaller for the next 40 million years. The phenomenon is known as the Lilliput Effect and holds that mass extinctions lead to smaller statures among animals, according to The Washington Post.
"Rather than having this thriving ecosystem of large things, you may have one gigantic relict, but otherwise everything is the size of a sardine," study lead author Lauren Sallan, an assistant professor in of Earth and environmental science at the University of Pennsylvania's School of Arts & Sciences, said in a press release. "There were fish called arthrodire placoderms with large slashing jaws that were the size of school buses, and there were relatives of living tetrapods, or land-dwelling vertebrates, that were almost as large.
"You had some vertebrates that are small, but the majority of residents in ecosystems, from bottom dweller to apex predator, were a meter or more long."
The research comes at a time where some studies suggest the Earth will experience its sixth mass extinction. Additionally, climate change and sea level rise are on the forefront of discussions among world leaders.
"It doesn't matter what is eliminating the large fish or what is making ecosystems unstable," Sallan said. "These disturbances are shifting natural selection so that smaller, faster-reproducing fish are more likely to keep going, and it could take a really long time to get those bigger fish back in any sizable way."
