16-04-2025
They're not the prettiest, but they survived 2 extinction events
Garbage in, garbage out. High protein, low fat. Cut the carbs and stay hydrated.
It turns out it does matter what you eat, especially to crocodylians — crocodiles, alligators and gharials — a species researchers say persisted despite two mass extinction events because they adapted their diet and the places where they found food.
'Lots of groups closely related to crocodylians were more diverse, more abundant, and exhibited different ecologies, yet they all disappeared except these few generalist crocodylians alive today,' said the lead author Keegan Melstrom. 'Extinction and survivorship are two sides of the same coin. Through all mass extinctions, some groups manage to persist and diversify. What can we learn by studying the deeper evolutionary patterns imparted by these events?'
Researchers reconstructed their dietary ecololgy by examining the teeth and skulls of 99 extinct crocodylomorph species and 20 living crocodylian species.
The research is the first to reconstruct the dietary ecology of crocodylomorphs to identify characteristics that helped some groups persist and thrive through two mass extinctions — the end-Triassic, about 201.4 million years ago, and the end-Cretaceous, about 66 million years ago.
Their study was published in the journal Paleontology on Tuesday.
'Despite being stereotyped as 'living fossils', the characteristics that facilitated their survival remain largely unknown, but trends in other clades, such as mammals, suggest that dietary ecology may play a key role in persisting during and after mass extinctions,' an abstract of the study said.
Earth has gone through five mass extinctions in its history — and experts would argue we are undergoing a sixth — so the gritty survival of these toothy animals may provide tools on how to better protect vulnerable species today.
Take the gharial, with its long, thin jaws it uses to feed on fish. Populations were once distributed across Bangladesh, Bhutan, India, Myanmar, Nepal and Pakistan. It currently survives in several severely fragmented populations in India and Nepal and is down to less than 250 in numbers.
It thrives in big rivers and with its elongated snout and interlocking teeth, adults can quickly snatch a fish. Juveniles munch on insects, crustaceans and frogs.
Males can reach up to 20 feet in length, but you don't have to worry about this gigantic creature chasing after you on land because of its weak leg muscles. When it does move across land, think of belly slides.
The species is critically endangered, with India granting full protection in the 1970s. Habitat fragmentation, the damming of rivers and hunting are all factors that have this animal on collision course for extinction.
Melstrom, an assistant professor at the University of Oklahoma, teamed up with Randy Irmis, curator of paleontology at the Natural History Museum of Utah and a professor in the University of Utah's Department of Geology & Geophysics, to conduct the research probing the dietary ecology of the species that for now have withstood all the tribulations of time.
'We propose that one reason for the success and longevity of the crocodylomorph clade is their remarkable dietary flexibility, a characteristic that is still observed in living crocodylians,' the study says.
A clade is a grouping that includes a common ancestor and all the descendants (living and extinct) of that ancestor.
The team studied a fossil dataset that spans six continents and 200 million years of evolutionary history.
'Crocodylomorphs have survived two major mass extinctions and may be on the cusp of a third,' the research said, underscoring the need for better conservation practices and using science to help stave off extinction.
As an example, the gharials are a keystone species indicating the health of an entire river-based ecosystem.
Wildlife SOS says to save the species, you need to save their home.
Controlled repopulation efforts have been successful to a degree.
In 2024, 160 gharial eggs hatched across the Gandak River in Nepal after intense monitoring by federal officials, scientists and volunteers. The Gandak is a major left bank tributary of the Ganges in India.
But ultimately, the key to ensuring the long-term survival of this ancient species lies in restoring balance to the affected ecosystem and, of course, ensuring they stay on the right diet and adapt.
