Megafauna extinctions

Modern elephants once had numerous cousins, including the woolly mammoth, the mastodon and the gomphotheres. They were all recognisably elephant-like and belonged to a biological order called Proboscidea. (Proboscis is another word for trunk.)

Late Quaternary Extinctions

Why did the elephants’ cousins go extinct? Scientists can’t agree, but it’s thought climate change or the spread of humans are the likely causes.

Proboscidea extinction was part of a wider pattern. Many other large land animals also disappeared.

Starting from around 50,000 years ago, a wave of extinction hit Earth’s largest land creatures. Around two thirds of large animal genera went extinct on most continents. Scientists call these losses the Late Quaternary Extinctions (LQE). A defining feature of the LQE is that large animals took the brunt of it.

The following is a quote from the article “Learning from the past to prepare for the future: felids face continued threat from declining prey.” Click on the link to read the full text.

Between ∼100 000 and 1000 yr ago humans played an important role in the extinction of at least 166 large continental mammal species (≥ 10 kg) and the continental extirpation of a further 11 (Sandom et al. 2014). With the loss of aurochs Bos primigenius in 1627 (Tikhonov ), bluebuck Hippotragus leucophaeus in 1799 (IUCN ) and thylacine Thylacinus cynocephalus in 1936 (McKnight ) amongst many others (IUCN ), it is clear that this anthropogenic extirpation of large mammals continues.

Anthropocene Earth is not normal

There are relatively few large land animal species today because of the LQE.

Ice Age humans would find the 21st century strange for many reasons. An absence of really large land animals would be one of them.

We are so used to this world that to us the Ice Age seems like a time of giants. We look back and ask “why were Ice Age animals so big?”

That probably isn’t the best question. A better one may be “why are there so few very big animals today?”

The below is a quote from a very interesting article “Megafauna and ecosystem function from the Pleistocene to the Anthropocene,” published in PNAS volume 113 on January 26, 2016. To find out more about megafaunal impact on ecosystems click this link.

With the notable exception of a period following the end-Cretaceous mass extinction, megafauna have been almost continuously abundant in almost all of the landscapes and seascapes on Earth for hundreds of millions of years, including through multiple glacial-interglacial transitions and other periods of climate change. Then, mainly in the last 50,000 y, there has been a rapid decrease in large animal abundance and diversity.