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Megafauna

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The word megafauna means large (mega) animals (fauna). In the context in which we are using the term, we are referring to a group of animals that collectively died in mass extinction some 46,000 years ago. They were very large , generally weighed more than 50 kg in weight, and were at least 30% larger than any of their current relatives. Although many of them were marsupials ; including giant kangaroos and wombats, as well as other strange beasts like the marsupial lion, there were also huge snakes , lizards and birds. These animals had existed on earth for around 11 million years , then in just a few thousand years, most of these giant animals disappeared.

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What is megafauna?

The term megafauna refers to the group of animals that inhabited the earth in the Pleistocene period , which had large sizes and weights greater than 50 kg and that disappeared due to climate change and the actions of man .

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  • Characteristics of the megafauna
  • Origin of the megafauna
  • Evolution
  • Extinction
  • Representative species that make up the megafauna
  • Examples of megafauna by geographic area

Characteristics of the megafauna

The main characteristics of the megafauna were the following:

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  • The term refers to animals that were large in size .
  • Megafauna animals thrived during the Pleistocene period , the early Quaternary epoch .
  • They lived in a period of glaciations , which ended with the thaw.
  • Megafauna can be categorized into smaller groups such as mega carnivores , mega herbivores , and sometimes mega omnivores .
  • They were animals capable of reaching longevity with a slow rate of increase in their species and also a very slow rate of morbidity .
  • The digestion process of the animals occurred in the long intestine and their legs and fingers were ungulates .

Origin of the megafauna

Late Pleistocene and the Holocene that has been dying out in a process known as the Quaternary mass extinction , a stage that began approximately 50,000 years ago to the present day. It is believed that the origin of the megafauna was in Tibet , time before the Ice Age began . Experts believe that when the northern hemisphere was covered in water, the Tibetan rhinoceros had to descend and adapt to new environments, evolving to give rise to new species, just as other species did.

Evolution

The evolution of the megafauna had its origin with the mass extinction of the Tertiary Cretaceous period that eliminated the dinosaurs . This was the reason why land mammals increased their body size as their ecological niches changed . The maximum size of the animals increased by approximately 50 kilograms and managed to reach 750 g.

Carnivorous mammals managed to gain nearly 600 kilograms and tripled in size. Scientists believe that these changes occurred due to the drop in temperatures and the increase in the area on earth .

Extinction

During the late Pleistocene , approximately 125,000 years ago, this megafauna began to disappear and today there are none of these wonderful animals left. The reasons why they disappeared have been studied over the years, obtaining different reasons from these analyzes. Extinctions of the late Pleistocene megafauna occurred during the last glacial-interglacial transition , essentially during the last 130,000 years , and affected mammals , birds, and reptiles .

Causes of extinction

Mass extinctions did not happen at the same time nor were they universal , and the reasons researchers have given for those extinctions include climate change and human intervention .

One of the two main theories that tries to explain the reason for the disappearance of megafauna animals is the one that tells us that they failed to adapt to the different environmental changes that had been caused by natural global climate change during the time.

The other theory explains that the animals were hunted by humans until they caused their extinction. Man, having to hunt to eat and survive in times and places where there were not many food alternatives , chose to consume the different beasts. There are scientists who also affirm that these causes should be taken as one , since the environment , hunting and pressures made the extinction of the megafauna a reality .

Consequences of extinction

With the extinction of the megafauna there was also the extinction of some species of plants and the animals that survived were also affected. As there were not enough animals to eat plants, their overpopulation led to large fires and changes in the relationships between species and ecosystems .

In addition, some plants depended on the megafauna to be able to disperse their seeds causing them to become extinct, because although some of these trees and plants still survive, the animals that were left alive do not eat them causing their extinction .

Representative species that make up the megafauna

The main species and of which we generally have more knowledge are:

  • Mammoths : belonging to the genus Mammuthus, they are relatives of the elephants that we have today. They inhabited North America , Eurasia, and Africa for 4.8 million years. There were different species of them, the best known being the woolly mammoth . The largest known species was the Songhua River mammoth that became extinct at the end of the Pleistocene, measured more than 5 meters in height at the withers and could weigh more than 15 tons.
  • Saber Tooth Tiger – Known as Smilodon lived in America and became extinct in the final part of the last ice age . It is believed that their extinction was due to climate changes at the end of the Pleistocene, because they were hunted and because of diseases transmitted by humans and other animals.
  • The Megaterium : their name means “great beast” , and they were a species of giant terrestrial sloths that emerged about 5 million years ago in South America . They became extinct shortly after the last ice age, they were herbivorous and quadruped animals .
  • The megalocero or giant deer : it was the largest deer that has existed in history and lived in Europe and Asia . Herbivores, polygamous, with a strong sexual dimorphism.

Examples of megafauna by geographic area

  • Europe : among the most recognizable species of Eurasia are the mammoth woolly mammoth steppe, elephant straight tusks, aurochs, bison steppe , tiger Ngandong, cave lion, bear cave, cave hyena, Homotherium, elk Irish, bears giant polar rhino Woolly, Merck Rhino, Narrow-nosed Rhino, and Elasmotherium.
  • America : animals such as the western camel , the American lion , ancestral bison , mastodons , the hagerman horse , short-faced bear, Columbia mammoth, the Jefferson sloth, giant tortoises, American cheetahs , scimitar cat, deer- elk, the gigantic armadillo-like Glyptotherium, giant condors among others.
  • South America : one of the largest groups of mammals that existed in South America, were the Notoungulates , you could also find the Macrauquenia , Toxodontids that were animals very similar to hippopotamuses and the “terror birds” or Fororracos , in addition to the famous Sabretooth , megaterios, dliptodonts, toxodones.
  • Africa : Deinotherium a monster elephant , the ancycloterium that was a strange prehistoric relative of the horse, there were also dogs the size of wolves, saber-toothed and saber-toothed cats, such as Megantereon and Homotherium , which were actually the ancestors of the American Smilodon and the scimitar cat.

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