Nav: Home

Prey scarcity and competition led to extinction of ancient monster shark

March 31, 2016

Is there anyone out there who doesn't know Jaws, the film about the great white shark and the devastation it wreaked? But there have been even bigger and more dangerous sharks in the past: The largest shark in the history of the planet, Carcharocles megalodon, lived between 23 million and 2.6 million years ago, reaching body lengths of up to 18 meters and probably feeding on marine mammals. Then it became extinct. In the past, climate changes have generally been blamed for its disappearance. Now, for the first time, researchers from the University of Zurich have examined the geographical distribution of the megalodon over time and arrived at the following conclusion: The giant shark became extinct because the diversity of its prey decreased and new predators appeared as competitors.

200 records from all over the globe

The team surrounding Catalina Pimiento from the Paleontological Institute and Museum of the University of Zurich assessed roughly 200 megalodon records from museum collections and databases, ranging in age for more than 20 million years. Based on these data, the scientists reconstructed the range and the abundance of this prehistoric animal: In the early Miocene, up to approximately 16 million years ago, they were mainly found in the Northern Hemisphere in the warm waters off the coast of America, around Europe and in the Indian Ocean, but they later penetrated further into the Asian, Australian and South American coasts. Abundance of the species peaked in the middle Miocene, while the largest geographical coverage did not take place until the late Miocene. The continuous decline (see charts) followed around 5 million years ago with the gradual emergence of a glacial period during the Pliocene.

Food resources disappear

"We were not able to ascertain any direct link between the extinction of C. megalodon and the global fluctuations in temperatures during this time. Changing climatic conditions do not appear to have had any influence on the population density and range of the giant sharks," explains Pimiento. Their numbers did not decline in colder periods, nor did they increase significantly in rising water temperatures.

Instead, the evolutionary narrative of other species seems to have had an effect on the development of the monster sharks. When Megalodon range shrank, numerous smaller marine mammal species disappeared. The second factor was the appearance of new predators such as the ancestors of the killer whale and the great white shark. The results suggest that these species could have competed for the increasingly scarce food sources.
-end-


University of Zurich

Related Climate Articles:

Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
Incubating climate change
A group of James Cook University scientists led by Emeritus Professor Ross Alford has designed and built an inexpensive incubator that could boost research into how animals and plants will be affected by climate change.
And the Oscar goes to ... climate change
New research finds that Tweets and Google searches about climate change set new record highs after Leonardo DiCaprio's Academy Awards acceptance speech, suggesting celebrity advocacy for social issues on a big stage can motivate popular engagement.
Cod and climate
Researchers use the North Atlantic Oscillation as a predictive tool for managing an iconic fishery.
What hibernating toads tell us about climate
The ability to predict when toads come out of hibernation in southern Canada could provide valuable insights into the future effects of climate change on a range of animals and plants.
Maryland climate and health report identifies state's vulnerabilities to climate change
A new report by the University of Maryland School of Public Health and the Maryland Department of Health and Mental Hygiene details the impacts of climate change on the health of Marylanders now and in the future.

Related Climate Reading:

The Politically Incorrect Guide to Climate Change (The Politically Incorrect Guides)
by Marc Morano (Author)

Climate--A New Story
by Charles Eisenstein (Author)

The Climate Chronicles: Inconvenient Revelations You Won't Hear From Al Gore--And Others
by Joe Bastardi (Author)

Designing Climate Solutions: A Policy Guide for Low-Carbon Energy
by Hal Harvey (Author), Robbie Orvis (Author), Jeffrey Rissman (Author)

Climate Change: The Facts 2017
by Institute of Public Affairs

The Uninhabitable Earth: Life After Warming
by David Wallace-Wells (Author)

This Changes Everything: Capitalism vs. The Climate
by Naomi Klein (Author)

Climate Change: What Everyone Needs to Know®
by Oxford University Press

The Thinking Person's Guide to Climate Change
by Robert Henson (Author)

What We Think About When We Try Not To Think About Global Warming: Toward a New Psychology of Climate Action
by Per Espen Stoknes (Author), Jorgen Randers (Foreword)

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Bias And Perception
How does bias distort our thinking, our listening, our beliefs... and even our search results? How can we fight it? This hour, TED speakers explore ideas about the unconscious biases that shape us. Guests include writer and broadcaster Yassmin Abdel-Magied, climatologist J. Marshall Shepherd, journalist Andreas Ekström, and experimental psychologist Tony Salvador.
Now Playing: Science for the People

#514 Arctic Energy (Rebroadcast)
This week we're looking at how alternative energy works in the arctic. We speak to Louie Azzolini and Linda Todd from the Arctic Energy Alliance, a non-profit helping communities reduce their energy usage and transition to more affordable and sustainable forms of energy. And the lessons they're learning along the way can help those of us further south.