Introduction to Cenezoic Animals

Introduction to Cenezoic Animals

     Hello guys! I am sorry for not creating blog posts as often, but now I am back on track with a Thanksgiving day post. Today I will teach you about the Cenezoic, so enjoy.

     Lets admit it, we all know what a dinosaur is, giant reptiles that practically define prehistory, but dinosaurs were not the beginning, nor the end of prehistory as we know it. Let's go back to the Triassic period, a time when everyones favorite creatures were evolving, the dinosaurs. During this time, you could peek in holes in the ground and probably see something like this, this is what the ancestor of all modern mammals, even us, looked like.

Picture by: Carl Buell

     When dinosaurs ruled the earth, small mice and shrews scuttled underneath them, until the end of the cretaceous period. That meteor we have all heard of hit the earth in new Mexico and wiped out anything larger than a foot tall, it was time for the mammals to shine. In the fossil record, this is called the K.T boundary. K.T stands for cretaceous / Tertiary boundary. The tertiary is divided into two distinct periods, the Paleogene, and Neogene, where the mammals diversified into what they are today.

Paleogene period

     The paleogene was a period where these small shrews and mice became all the distinct groups of mammals these divisions of time might be confusing, but I will explain it as best as I can. The paleogene period was divided into even more sections of time. These sections of time are called epochs. The Tertiary started with the paleocene epoch (it's important not to get the paleocene, and paleogene mixed up) the time when certain creatures evolved. Most of all the first horses evolved which were about the size of overweight guinea pigs. Most early paleontologists nicknamed them "dawn horses". One example would be Hyracotherium, a small ground dwelling creature that evolved in the late paleocene. Surprisingly enough, the first horses did not have hooves. They had paws like dogs and bears.

     The second epoch during the Paleogene was the eocene epoch this is the time when many more things happened in mammal evolution, including the evolution of the first rhinos, and the continued evolution of horses. An interesting one was the evolution of whales. Meet Ambulocetus, the "walking whale" this creature lived during the eocene epoch and was the ancestor of all whales and dolphins. it looked more like a crocodile than a whale, but this creature is amazing.

Skeleton of ambylocetus
By: Wikipedia

     It's back tail would have gone up and down as it used webbed feet to swim through the water. Another strange group of creatures evolved later in the eocene, the Titanotheres. These creatures evolved off of those dawn horses and died out in the Oligicene epoch which came after the paleocene, from a distance, you might mistake one for a rhino, but these creatures were bigger. they had strange forked bones on their skulls which were probably used for defense against their predators, killer goats. Wait a minute, what? Yes! You heard me right, killer goats. Evolving from Ambulocetus, and it's close relative, Pakicetus, andrewsarchus (ANN-droo-sar-kiss) was a terryfying carnivore that had the first hooves, like sheep and goats.

Andrewsarchus Mongoliensis
2001 Documentary/Movie, Walking With Prehistoric Beasts

     The final epoch in the paleogene period was, the Oligicene epoch. Many more amazing creatures sprouted from evolution. The first pigs evolved, which were called Entelodonts. Entelodonts are nothing like the pigs living today. They were hunters, and they fed on grass which made them omnivores. They had tough, bony skin and were about the size of modern rhinoceroses.

Neogene Period

     The Neogene period is divided into epochs also, although it has less. More amazing evolution happened here. Starting with the Miocene epoch, where we could see our (Great, great, great, great, etc.) grandparents. This was australopithecus, the first primate to stand up on it's hind legs on solid ground. 

     After the Miocene, came the pliocene, when most of the life we had today had evolved and during the pliocene, the earth slowly cooled to prepare for what was coming next, what we call the ice age.

Pleistocene epoch

     The Pleistocene was the most recent prehistoric time period. A time when many famous prehistoric mammals evolved, including Smilodons, Dodos, and Mammoths. It was also when many of the recent mammals talked about in this post died out. There are many reasons, for instance, the land bridge we know call Central America came into existence and a swap between animals from north america and south america took place. Humans also evolved and may have been an influence in these extinctions. Probably the biggest factor though, was the fact that the world became very cold and icy. That was the ice age. 

     Now that you know about the Cenezoic, you should understand the upcoming posts on the blog.