Marine biologists believe that two-thirds of Ocean life remain undiscovered. This means that besides there being undiscovered species of fish in the vast bodies of water around the world, there are also undiscovered whale, dolphin, and shark species among other marine reptiles, plants, sponges, crustaceans, algae, etc that are still to be found. One marine animal that would not have been difficult to discover today is the now extinct Megalodon species of shark.
Megalodon, which translates to “big tooth” from Ancient Greek, roamed the oceans of the world millions of years ago during the geological epoch of the Early Miocene to the Pliocene. From fossil remains of the great ocean monster, scientists have estimated through reconstruction that it reached a maximum length of 18 meters (59 feet) and had an average size of 10.5 meters (34 feet), thus making it one of the largest and most powerful predators to have ever lived. It has further been estimated that its large jaws could exert a bite force of up to 110,000 to 180,000 newtons (25,000 to 40,000 lbf) and their teeth from which the name is derived from, were thick and robust, built specifically for the ability to grab prey and break bones.
Evolution and Habitat of the Prehistoric Shark
Megalodon, which is thought to be a robust-looking shark with a similar build to the Great White, was previously believed to have been closely related to the large mackerel shark that can be found today in the coastal surface waters of all the major oceans in the world. This would have made it a member of the family Lamnidae.
Recent discoveries and further research have, however, debunked this as there is an almost unanimous agreement between marine scientists that it belongs to the extinct family Otodontidae, a species that diverged from the family Lamnidae during the geographical period of the Early Cretaceous. Scientists have however been unable to agree on its genius, with Carcharocles, Megaselachus, Otodus, or Procarcharodon listed as possible placements.
With excavations of fossils (teeth, vertebral centra, and coprolites) having occurred in many parts of the world, including Europe, Africa, the Americas, and Australia, it is believed that the Megadolon had a cosmopolitan distribution, occurring commonly in subtropical to temperate latitudes.
Why Megalodon Went Extinct
There are a number of theories that try to explain why Megalodon went extinct millions of years ago. Some of the more plausible theories that have been put forward by marine scientists have to do with the changes earth experienced during the Oligocene and Pliocene such as climate change and changing ecosystems.
1. Climate Change
The Oligocene era, 35 million years ago, brought glaciation at the poles and led to changing currents and precipitation as well as an increase in the coolness of the oceans. This hindered the Gulf Stream from reaching major marine ecosystems, preventing marine life from receiving nutrient-rich water and thus affecting the food sources of Megadolon and other animals of the time that have gone extinct.
It is believed that the shark’s range did not particularly extend into colder waters due to the fact that its body was unable to retain a significant amount of heat, leaving it with no option but to restrict itself to shrinking warmer water bodies. These decreasing warm waters were also the most suitable nursery sites for Megalodon, so with it being unable to successfully reproduce and nurse its offspring, its extinction was almost inevitable.
2. Changing Ecosystems
Due to its size, it is believed that Megalodon may have been too large to sustain itself in a time when there was a decline in marine food resources. Many marine species are believed to have gone extinct at the end of the Miocene era with those surviving presumed to have been very fast swimmers and thus more elusive to predators.
The Central American Seaway is further believed to have closed during that time period, leading to a decrease in the diversity and abundance of tropical whales, which was a huge food source of the prehistoric whale eating shark which needed to feed heavy due to its size. Competition from other large marine predators such as macro predatory sperm whales, killer whales, and great white sharks in the Pliocene further doomed the existence of Megalodon.