[ad_1]
The megalodons’ dependence on nurseries may have contributed to the end of their 20-million-year reign, the researchers conclude in a new study.
PARIS: The largest sharks to ever roam the oceans parked their young in warm, shallow water nurseries where food was plentiful and predators were in short supply until they could assume their title of king and queen of the sea.
But as sea levels dropped in a cooling world, the brutal mega-predator, Otodus megalodons, may have found fewer and fewer safe coastal areas where its young could safely reach adulthood, researchers reported Wednesday in the report. Biology Letters journal of the Royal Society.
In fact, Megalodon’s dependence on nurseries may have contributed to the end of their 20-million-year reign, according to research.
Otodus megalodon – sometimes classified as a Carcharocles megalodon – took 25 years to become an adult – “extremely retarded sexual maturity,” the authors said in the research paper.
But once fully grown, the shark could reach 60 feet, three times the size of the largest white shark, made famous by the 1975 hit Jaws.
As an apex predator, and until its extinction about three million years ago, the adult megalodon was unrivaled among other ocean hunters and fed on smaller sharks and even whales.
But its young were vulnerable to attacks from other predators, often other razor-toothed sharks.
Nurseries on shallow continental shelves with vast smaller fish for food and few competing predators have given them the perfect space to reach their impressive size.
“Our results reveal, for the first time, that nursery areas were commonly used by O. megalodon on large time and spatial scales,” the authors said.
–‘Perfect nursery’–
The research team discovered a nursery area off the east coast of Spain in the province of Tarragona after visiting a museum and observing a collection of megalodon teeth.
“Many of them were quite small for such a large animal,” British University of Bristol authors Carlos Martinez-Perez and Humberto Ferron told AFP.
Judging by the size of the teeth, they speculated that the area was once home to young megalodons.
The Spanish nursery could be described as “a perfect place to grow,” the authors said.
It would be a “shallow bay of warm waters, connected to the sea and with extensive coral reefs and an abundance of invertebrates, fish species, marine mammals and other sharks and rays.”
The researchers analyzed eight other sets of shark teeth that had previously been collected, scattered across the United States, Peru, Panama and Chile.
They concluded that four of them – two in the United States and two in Panama – belonged to younger sharks.
Consequently, the authors suggest that these four areas where the teeth were found may also have been nurseries.
“The remaining four formations … demonstrate structures classified as typical sizes of adult-dominated populations, suggesting that these regions could correspond to feeding or mating areas,” the study states.
Sharks continuously lose their teeth throughout their lives and nurseries are areas with a high abundance of sharks.
“As a result, huge numbers of teeth can be lost, increasing the chances of later fossil discoveries,” the authors said.
Megalodons enjoyed the warm and temperate waters of the Miocene period which stretched from about five million to 23 million years ago.
But the colder period of the Pliocene was much less suitable for them.
As their prey adapted and headed for colder waters, the megalodon stayed where the oceans remained warm.
The leftover food was also favored by the great white sharks, increasing competition with the smaller, but more agile predator.
The large reduction in shallow-water nurseries due to sea level losses – caused by a cooler climate – may also have contributed to the eventual extinction of the megalodon.
Source link
