The first indisputable signs of life began nearly 3.4 billion years ago, and since then life has dramatically evolved in ways and factors unlike anything we see on earth today. From giant land scorpions to extinct crocodiles the length of a school bus, explore interesting animals that walked (or swam) the earth long before humans.

Pulmonoscorpius

Generally, most modern species of scorpions are smaller than the size of an average human hand. It is also relatively harmless (except for some species, which has a very toxic and potentially lethal venom).

However, if you were to time travel to the Carboniferous Period, roughly 360 million years ago, you might be unlucky enough to come across Pulmonoscorpius kirktonensis, a giant land scorpion that was almost half the length of an adult human. Measuring over 2.5 feet, it likely killed its prey by ambushing it and then repeatedly stabbing it with its stinger. And like its modern relative, Pulmonoscorpius was probably poisonous. Paleontologists also estimated that it had relatively good eyesight thanks to its abnormally large eyes.

The early earth had abundant plant life. The earliest gymnosperms, such as primitive cycads, horsetails, and club mosses, thrived in the moist atmosphere of early earth. As a result, the oxygen concentration in the atmosphere was higher than current estimates, which in turn directly affected the size of the prehistoric insects. Like Pulmonoscorpius, other prehistoric insects such as Meganeura (ancient dragonflies) and Arthropleura (ancient millipedes) also grew to giant sizes due to the higher concentration of oxygen in the atmosphere.

Hallucination

In 1977, Simon Conway-Morris, a British paleontologist came across a very strange, thumb-sized fossil collected in the Canadian Rockies. Initially, Morris speculated that the fossil was an annelid worm, similar to leeches and earthworms. It had seven spikes that would have been used as its “feet” and seven tentacles that waved off its back. He named the creature Hallucigenia, due to its strange and almost dreamlike appearance.

The Conway-Morris model of the creature was highly controversial, however it managed to be relevant until 1991. By then, Chinese researchers had stumbled upon a similar fossil, called the Microdictyon, which had plate-shaped scales instead. of seven peaks. who had Hallucigenia. The researchers were able to deduce that the tentacle-like structures on the back of Hallucigenia were actually feet. So for more than a decade, the scientific community has been looking at the Hallucigenia fossil upside down.

Even today, almost 50 years after the discovery of this fossil, new discoveries are being made. Scientists have recently found the location of its head after examining its fossil under an electron microscope. Hallucigenia is appropriately named after it, it remains one of the strangest creatures found to date.

Saber-toothed tiger

Today, big cats like lions and tigers are the apex predators in almost every known terrestrial food chain. But 10,000 years ago, the plains of North and South America were home to the Smilodon, or the saber-toothed tiger. S. populator was the largest of the species, weighing more than 400 kg. In addition, they are much larger than most other large cats, such as the Bengal tiger.

One of the characteristic features of the smilodon is the very long dagger-shaped canines. His teeth were so long that they protruded from his mouth by a significant margin. It even had an incredibly wide opening to accommodate those fangs, opening its mouth up to 120 degrees, which would have been a pretty impressive and threatening sight if it were alive today.

However, their canines were slender, razor-shaped, and quite fragile. Therefore, it was more adapted for precision movements such as slashing, slicing, and stabbing. Furthermore, an extremely wide opening meant that the animal had a lower bite force, this meant that its bite force was not proportional to its body size. Consequently, the bodies of these animals became more robust and robust to immobilize prey.

These big cats were specialized in taking down large mammals such as extinct bison, giant ground sloths, and even juvenile mammoths. However, their prey began to die and was replaced by smaller, more agile prey like the ancestors of deer. As these apex predators were unable to adapt to these new prey, the population began to decline and eventually became extinct.

Gigantopithecus

Humans belong to the Hominidae family, (also called as the great apes) and we are the only surviving member of this species today. But nearly nine million years ago, Asia was home to one of the largest primates to ever walk the earth: Gigantopithecus blacki.

This giant great ape towered over 10 feet tall and weighed between 550-600 kg, making it almost 3-4 times heavier than modern gorillas. However, scientists have theorized that it is more closely related to modern orangutans after analyzing its morphology. But not much else is known about this great ape, as fossil evidence is limited to a few teeth and fragments of a jaw bone.

When it was alive, its habitat consisted of a mosaic of savannas and wooded areas. Analysis of his teeth implied that he subsisted purely on a diet of fruit and bamboo shoots, much like gorillas today. However, its habitat was reduced due to climate change and it was unable to adapt due to its enormous size and strict diet selection. The last Gigantopithecus became extinct about 100,000 years ago.

Explore more interesting topics about BYJU. From cellular organelles and centrosomes to endangered species and mass extinctions, BYJU is your best resource for education and learning. Explore in-depth articles and fascinating videos on all your favorite science topics by signing up today.