La Oligocene epoch was the third and last of the eras that formed the Paleogene period of the era of Cenozoic. It is a period of time in which the planet experienced notable changes in terms of living beings and geology. Oligocene fauna was able to thrive thanks to a fundamental change in climate that created ideal conditions for animals and plants to thrive.
In this article we are going to tell you about all the characteristics and evolution of the Oligocene fauna.
Oligocene epoch
This era began approximately about 34 million years and ended about 23 million years ago. Throughout this time the planet underwent noticeable changes. The climate played a fundamental role in the development of flora and fauna. These changes in the planet caused that the animals had to redistribute themselves throughout the planet.
The Oligocene has been a time that has fascinated specialists in the study of geological time since they have dedicated enough time and effort to elucidate the most hidden aspects. The Oligocene duration is approximately 11 million years and, during this time, the movements of the tectonic plates continued, reaching positions similar to those they have today.
The Oligocene fauna is famous for being known as the Age of Mammals. The mammal group experienced the greatest diversification and variety during this period. Thanks to the development and spread of animals, well-known subdivisions such as rodents and canids were created. What stands out the most from the geology of this time is the Laramide orogeny and the Alpine orogeny.
As for the climate, the conditions that characterized this era were quite extreme. It was characterized by very low temperatures that kept the poles covered in ice. Some ecosystems were modified by the global temperature drop. Let's take a closer look at life.
Flora
The Oligocene flora is characterized mainly by the coniferous forests that predominated together with the deciduous forests. These forests are prepared to be able to survive low temperatures. Angiosperms began to spread to a large number of habitats, reaching a great dominance. In addition, its evolution can be better understood if we consider the context of the Paleogene fauna and its influence on the evolution of mammals.
Due to the cold climate, a decline in tropical forests was observed, replaced by herbaceous plants and grasslands. Various types of plants had to cope with the action of grazing animals that feed on them. Let's analyze what these animals are.
Oligocene fauna
The Oligocene fauna is characterized by having many groups of animals that managed to diversify and prosper despite the climatic conditions in which they were found. In these more diversified groups of animals we find birds, reptiles and mammals. Some scientists call the Oligocene fauna the age of mammals. It is about the time of the Cenozoic era what else could proliferate in terms of mammals.
A large number of new mammal species appeared, including rodents, canids, primates, and cetaceans. Let's analyze each of them.
Rodents
Within the rodent order, we find a more abundant group of mammals that developed during the Oligocene fauna. Their characteristic, which helped distinguish them from the rest, was their very sharp incisors with multiple uses. One of them is to bite predators or gnaw on wood. The best-known Oligocene rodent family was the Eomyidae. They were similar to modern squirrels but smaller and arboreal. To learn more about the evolution of these mammals, see our article on .
Primates
They are a group of mammals characterized by having five toes. One of the main advantages of these primates over other mammals is their opposable thumb. They also have plantigrade feet, which allow them to support the entire sole of their feet while moving. Their tooth pattern is generalized and not very specialized. The primates that can be observed more frequently at this time were the lemur and the tarsier. For more information about lemurs, you can check out our article on its current situation and threats.
The tarsier is a cousin of the tarsier, measuring approximately 10 centimeters. Its main characteristic is its large eyes, which allow it to adapt its vision to the dark. Its diet is entirely based on insects and it spends most of its time perched on tree branches.
On the other hand, The lemur is a primate that can have varying sizes depending on the subspecies. One of their most notable characteristics is their long tail. This tail is often longer than their entire body. Their eyes are large and allow them to see in the dark. They don't distinguish colors well, but they can distinguish shapes.
Oligocene fauna: canids
Within the canids, they belong to the group of wolves and dogs. Their main characteristic is having a medium-sized body and walking supported on the tips of their toes. They are carnivorous, and many of them are predators. They appeared in the Eocene and later diversified. The evolution of these carnivorous mammals in relation to climate can be better understood by reading about the impact of the Ice Age.
Cetaceans
The group of mammals that has been able to adapt the most to marine life. Its main characteristics are its forelimbs modified to be able to become fins. Their hind flippers have disappeared over time. Their respiration is pulmonary, so they must frequently rise to the surface to take in the air.
During the Oligocene fauna one of the largest land mammals developed. It is known as the Paraceratherium. It had the approximate measurements of almost 8 meters high and 7 meters longThey were herbivorous animals with a highly developed sense of smell. They weren't at all sociable, but rather led a solitary lifestyle. Apparently, they fought among themselves by butting heads, protected by skull bones that were much thicker than normal.
I hope that with this information you can learn more about the Oligocene fauna.
