The earliest forms of life, microbes, date back approximately 3.7 billion years. They slowly transformed, presenting more and more complex organisms which eventually led to the formation of the first animal species. You might be surprised to learn that sponges, also known as poriferans, are considered to be one of the earliest animals in existence.

However, most of the images on this list depict something slightly larger and more menacing than the sponges. Take dinosaurs, for example. Scientists believe they lived around 245 to 66 million years ago, during the Mesozoic era, and could weigh tens of tons each.

The American Museum of Natural History (AMNH) revealed that some dinosaurs weighed up to 80 tons and were around 120 feet long. To put things into perspective, try imagining a dinosaur standing near the Leaning Tower of Pisa, measuring nearly two-thirds of its height.

The AMNH also pointed out that not all dinosaurs were extinct. Birds, also known as avian dinosaurs, actually share an ancestor with non-avians, making them the last surviving group of their genus.

As far as non-avian dinosaurs are concerned, about 300 genera and 700 species have been discovered and named. But those numbers are likely to increase further as scientists continue to find new fossils.

Thanks to paleontologists, we can better understand what the creatures that roamed the Earth looked like millions of years ago. They study the history of life from fossils, rocks that contain the remains of plants, animals or other forms of life.

It takes 10,000 years for such preserved remains to become fossils. In their hardened layers, they provide scientists with information about the organism’s environment, living conditions, and other details.

Some of the earliest fossils recognized as dinosaur remains date back to the 1830s. It was then, according to American paleontologist Mark Norell, that people in the English countryside discovered what they believed to be giant extinct reptiles. .

When it comes to the first person to study fossils, Georges Cuvier is often referred to as the founding father of paleontology. In the 19th century, he was a faculty member of the National Museum of Natural Sciences in Paris, which gave him access to the most extensive collection of fossils available at the time.

The images of remains on this list are only a tiny fraction of what has been excavated in recent years. However, they show how exceptional the creatures were in size and other characteristics.

Other examples of these fascinating excavations were presented in an article by Geology Science. In addition to the famous T-rex, it also covered extinct types of feathered dinosaurs and fish, as well as human remains dating back millions of years.

The Smithsonian Channel also covered the process of restoring an incredible 110 million year old fossil. Found in an oil sands mine, it turned out to be the remains of an 18-foot-long nodosaur, a type of nearly 3,000-pound armored animal with spikes on its shoulders and a long tail.

However, not all animal remains are encapsulated in fossils. Some are often found perfectly preserved in other formations, such as amber for example. (The Earth Archive has covered some pretty impressive examples, which you can find here.)

The colored tree resin traps certain organisms, which become completely enclosed as it solidifies. Although they are usually smaller in size, the amber pieces hold the remains of different species, thus also safeguarding information about them.

Most of the fossilized remains are of long-extinct beings, whether dinosaurs or other creatures. However, some species of animals disappeared only a few years ago.

Some examples include the Spix’s Macaw, also known as the Blue Macaw, featured in the animated film ‘Rio’, the smooth handfish that roamed the coastal waters of Tasmania, and the splendid poison dart frog, a red-colored frog once found in western Panama.

A surprisingly large number of nature’s creations are now on the brink of extinction. According to Animals Around The Globe, nearly 41,500 species are on the International Union for Conservation of Nature’s Red List, of which more than 16,000 are threatened with extinction.

For example, there are only 67 Javanese rhinos in the whole world. The numbers of mountain gorillas and Asian elephants are declining rapidly, as is that of Atlantic bluefin tuna.

The United States Geological Survey pointed out that some of the reasons for the unfortunate changes in these numbers are habitat loss and the overexploitation of wildlife for commercial purposes. Unfortunately, human activity has made the process of extinction much faster than it would have been naturally. Scientists believe that the mortality rate of animal species in the 20th century is a hundred times higher than it would have been without human intervention.

There are, however, ways to help save endangered animals. The Endangered Species Coalition has outlined some easy steps to do so, such as learning more about endangered species in your area or making your environment wildlife-friendly. He also highlighted the importance of recycling, safe driving and the safe use of chemicals in your environment.