Megalodon Mystery: What killed Earth’s largest shark?

Date:

Share post:

Megalodon, the most massive shark ever to prowl the oceans, may have gotten so big that it was prone to extinction.

Megalodon Mystery: What killed Earth's largest shark?
A Megalodon Shark [Credit: Giovanni Bianucci/LiveScience]

For some mysterious reason, though the biggest and smallest members of the species were the same length, many of the giant sea monsters got longer over a 14-million-year period, and then, they all went extinct, new research suggests..

Although it’s not clear why the behemoths were getting bigger over evolutionary time, their big size may have made them more vulnerable to extinction, said study co-author Catalina Pimiento, a biology doctoral candidate at the University of Florida and the Smithsonian Tropical Research Institute in Panama. She presented her findings here at the 73rd annual Society of Vertebrate Paleontology meeting.

Bigger is better?

Megalodon could grow up to 60 feet (18 meters) long and had a bite more powerful than that of a Tyrannosaurus rex. The sea monsters terrorized the oceans from about 16 million to 2 million years ago. Though that may seem like a long reign, other shark species have survived for 50 million years or more without significant changes in body plan, Pimiento said.

Megalodon Mystery: What killed Earth's largest shark?
Megalodon teeth from around the world (Credit: Catalina Pimiento/
LiveScience]

“This species is not as successful as we think,” Pimiento said. “A lot of sharks that were alive during the time of Megalodon are still around today.”

Megalodon’s short history made Pimiento ask whether the shark’s body size affected its evolutionary success.

“Body size affects nearly every aspect of an organism’s biology and ecology,” Pimiento told LiveScience. “When you have a very large organism like Megalodon, that can be very good or very bad.”

Bigger animals can eat a wider range of foods and be fiercer predators than their pip-squeak pals. But because they eat more types of animals they also have more competition for those animals, and the ecosystem can support a lower population density of them since they need more resources — including space — to survive. When food supplies dwindled, these giant creatures could have had a tough time finding enough food, Pimiento said.

Bigger over time

Pimiento went to several museums around the world and measured the tooth size of about 400 specimens of Megalodon. Based on those measurements, she estimated their final body size before extinction.

Megalodon Mystery: What killed Earth's largest shark?
A great white shark compared with the much larger megalodon, and a hapless
hypothetical human.(Credit: LiveScience]

She concluded that while the size of the biggest and smallest of the animals didn’t change over time, there were more of the bigger beasts during the later periods of its evolution.

It’s still not clear exactly why the behemoths got bigger, but Pimiento plans to look at climate data and information on other species to tease that out.

“Perhaps something was going on with the productivity and climate that produced that pattern, or with their prey and their competitors that made the species become large,” Pimiento said.

Either way, being so huge may have made them more vulnerable to extinction. Though the mega-sharks died off, their close relatives — great white sharks — still terrorize the seas today.

“The possible body size increase in the megalodon lineage over geologic time will need to be tested further by examining megalodon collections throughout the world, but the idea is important to understand the rise and extinction of the top predator lineage that must have had a significant impact to the ocean ecology,” said Kenshu Shimada, a paleobiologist at DePaul University in Chicago, who was not involved in the study.

Author: Tia Ghose | Source: Livescience [November 04, 2013]

ADVERTISEMENT

spot_img

Related articles

More on Human ancestor was less chimp-like than thought

An analysis of the femur of one of the oldest human ancestors reveals the six-million-year-old "Millenium Man" was...

Snake eats lizard eats beetle: Fossil food chain from the Messel Pit examined

In cooperation with CONICET in Argentina, Senckenberg scientists examined a spectacular discovery from the UNESCO World Heritage site...

Spanish hotel built on 15th century synagogue

A Spanish hotel built on the remains of a 15th century synagogue opened a new synagogue on its...

Archaeologists reveal Qatar’s historic sites

Experts from a Welsh university are helping a Gulf state reveal the secrets of its past through a...

New knowledge about the remarkable properties of black holes

Black holes are surrounded by many mysteries, but now researchers from the Niels Bohr Institute, among others, have...

Study says climate cycles are driving wars

In the first study of its kind, researchers have linked a natural global climate cycle to periodic increases...

Cumbrian man unearths Roman treasures in field near Silloth

John Murray, 66, was amazed to find 308 Roman coins, some thought to be nearly 2,000 years old....

15 million-year-old whale skull found on banks of Potomac River

From the banks of the Potomac River, in a region steeped in American history, a massive fossil was...