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The Prehistoric World In Video

Over 99.9% of all species that have ever lived are now extinct. At ExtinctZoo, we aim to provide meaningful information about the world and these animals that existed hundreds, thousands and even millions of years ago.

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The Prehistoric World In Video

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An expertly curated list if I do say so myself

145 Mya

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A Brief Look At Earth’s Zoo Through Time

Earth’s history is divided into 4 eons, 10 eras, and 22 geological periods, which together span from the formation of our planet 4.6 billion years ago to the present day. Single-celled organisms dominated the majority of this time, with multicellular organisms finally evolving around 1.5 billion years ago. The first animals appeared much later, during the Ediacaran period, about 635 million years ago, and life has been evolving in amazing ways ever since.

Cyanobacteria

Cyanobacteria are among the earliest known forms of life on Earth, appearing during the Archaean Eon over 3 billion years ago. These microscopic organisms were pioneers of photosynthesis, using sunlight to produce energy and releasing oxygen as a byproduct. This process dramatically changed Earth’s atmosphere, eventually leading to the Great Oxygenation Event during the Siderian period (2.5 mya). Cyanobacteria are also responsible for creating the world’s first identifiable fossils, known as stromatolites. These layered rock structures formed as cyanobacterial mats trapped and cemented sediment over time. Stromatolites provide crucial evidence of early life on Earth and can still be found in a few locations today, such as Shark Bay in Western Australia.

Eukaryotic cells

The Paleoproterozoic Era, spanning from 2.5 to 1.6 billion years ago, saw one of the most significant events in the history of life: the emergence of eukaryotic cells. Eukaryotes likely arose through symbiogenesis between a archaea and bacteria, which gave rise to the complex cellular structure characteristic of all Eukaryotes today (which includes animals). However, due to the difficulty of cell fossilization and the lack of preserved remains, identifying the first eukaryotic ancestor remains challenging. The oldest known fossils that can be confidently assigned to the eukaryote domain are acritarchs. These microscopic organic remains, typically spherical and found in marine sediments, date back to about 1.6 billion years ago. While their exact biological affinity is often unclear, some acritarchs are thought to be the resting cysts of algae or other planktonic organisms.

Kimberella

Kimberella was an organism that lived around 555 million years ago during the Ediacaran period. This was a key time in Earth’s history, as it featured some of the earliest known forms of complex animal life, which are collectively known as Ediacaran biota. Kimberella, a member of this group, is also one of the earliest probable known bilaterians – organisms with bilateral symmetry (i.e., the majority of all terrestrial animals). This oval-shaped creature, up to 15 cm in length, is believed to have been mobile, with a muscular foot for locomotion and a possible radula-like feeding apparatus for scraping algal mats. Its body plan, with a distinct front and back, is a characteristic shared by the majority of modern animals, including humans. Kimberella inhabited shallow marine environments, living in well-oxygenated waters up to tens of meters deep. It likely grazed on microbial mats and benthic bacteria and algae, which had undergone their own ecological “big bang” about 650 million years ago, providing a nutrient-rich diet for early animals.

Anomalocaris

Anomalocaris was a genus of extinct marine animals that lived approximately 520-499 million years ago during the Cambrian period. This bizarre creature could grow up to 1.2 feet in body length (excluding appendages and tail) and had a distinctive appearance. It possessed a segmented body, a pair of large, flexible frontal appendages used for capturing prey, and most notably, large stalked compound eyes that were among the earliest examples of complex eyes in the fossil record. Its circular, disk-like mouth was ringed with sharp, teeth-like serrations. Based on this unique body plan and the structure of its appendages, scientists first thought Anomalocaris was a member of the arthropod group, but is now believed to be an order of stem-group arthropods, meaning close relatives but not true arthropods themselves. Its physical features, particularly its large size, powerful appendages, and advanced sensory organs, indicated that Anomalocaris was a predator, and in fact, is considered one of the earliest known examples of an apex predator, likely sitting at the top of the Cambrian food chain and feeding on various smaller animals, including trilobites.

Endoceras

Endoceras was a genus of large nautiloid that lived approximately 470 to 443 million years ago during the Middle to Late Ordovician period. Along with its close relative Cameroceras, it was one of the largest animals of its time, with the largest confirmed specimen measuring 3 meters (9.8 feet) as preserved, and estimates suggesting complete sizes of approximately 5.73 meters (18.8 feet). Some unconfirmed reports suggest specimens reaching up to 9.1 meters (30 feet). Due to their hefty shells they had more limited mobility, but they could still achieve considerable speed through jet propulsion using their large funnels. However they mainly hunted through ambushes where Endoceras would likely lay in wait on the seafloor before using their strong arms to strike at passing prey and then shearing them apart with their sharp, chitinous beaks. Their diet likely included arthropods, mollusks, fish, and other cephalopods, with trilobites being their primary prey.With their size and hunting prowess it dominated the shallow equatorial oceans of the Ordovician as apex predators until their extinction during the Late Ordovician mass extinction 445 million years ago.

Pterygotus

Pterygotus was a genus of giant eurypterid that lived approximately 428 to 372.2 million years ago during the Middle Silurian to Late Devonian periods. Though not the largest of the pterygotids, it was still an impressive predator, with the largest species P. grandidentatus reaching lengths of 1.75 meters (5.7 feet). Like its close relatives, Pterygotus was characterized by powerful enlarged cheliceral claws that were perfectly adapted for active prey capture, with well-developed teeth for gripping and puncturing prey. Its compound eyes provided excellent visual acuity comparable to modern predatory arthropods, making it an efficient hunter in its aquatic environment. As an active and visual predator, Pterygotus would have been one of the top predators of its time, using its paddle-shaped telson (tail segment) as a rudder while swimming to pursue prey. The genus achieved a nearly worldwide distribution, with fossils found across Europe, North America, South America, and Australia, and its various species inhabited both marine environments and freshwater systems like lakes and rivers.

Dunkleosteus

Dunkleosteus was a genus of large armored fish that lived approximately 382-358 million years ago during the Late Devonian period. This imposing creature could grow up to 10 meters in length and was characterized by its massive, armored head and trunk. Instead of teeth, Dunkleosteus possessed two pairs of sharp bony plates that formed a beak-like structure in its jaws. Its skull was covered in articulated armor plates, giving it a fearsome appearance, while its rear portion was likely more flexible and covered in scales. Based on its fossil remains and jaw structure, Dunkleosteus is classified as a placoderm, an extinct class of armored fish that were among the first jawed vertebrates. The powerful jaw structure and large size of Dunkleosteus indicate that it was an apex predator in the Devonian seas. It likely fed on other armored fish, sharks, and possibly even its own kind.

Meganeura

Meganeura was a genus of enormous insect that lived approximately 305 – 299 million years ago during the Late Carboniferous period. This prehistoric creature resembled a dragonfly but on a much larger scale, with a wingspan reaching up 75 cm cm (2.46 ft), making it one of the largest known flying insects in Earth’s history. It had a long, slender body, large compound eyes, and two pairs of long, transparent wings. The wings were strengthened by intricate vein patterns, allowing for powerful and agile flight. Meganeura belongs to the order Meganisoptera, often referred to as griffinflies, which are extinct relatives of modern dragonflies and damselflies. Its massive size is believed to have been possible due to the higher oxygen content in the Earth’s atmosphere during the Carboniferous period, which allowed for more efficient respiration through the insect’s tracheal system. As a predator, Meganeura likely fed on other insects and possibly small vertebrates, occupying a significant niche in the Carboniferous ecosystem.

Inostrancevia

Inostrancevia was a genus of large predator that lived during the Late Permian period, approximately 259 to 252 million years ago. This formidable creature was one of the largest terrestrial animals at the time, with exceptional specimens reaching over 3.5 meters (11 feet) in length and weighing over 453 kilograms (1000 lbs), comparable in size to a large bear. Inostrancevia had a distinctive appearance characterized by a long, narrow skull, deep-set teeth, and most notably, elongated canines that could reach 15 cm (6 inches) in length, making it one of the first saber-toothed predators, predating the famous Smilodon by about 250 million years. Inostrancevia belonged to the clade of animals known as the gorgonopsids, a group of therapsids. As therapsids, gorgonopsids were part of the larger clade of synapsids, which includes mammals and their ancestors, making them more closely related to mammals than to reptiles. Inostrancevia possessed sturdy, long limbs that made it both durable and surprisingly fast for its size, allowing it to be an apex predator with a widespread range that included parts of Africa, Asia, and European Russia. It was highly adaptable, thriving in various environments from warm floodplains in South Africa to cold, arid deserts in Russia, and likely employed either a neck-targeting or bite-and-run hunting strategy to bring down its prey.

Coelophysis

Coelophysis was a genus of theropod dinosaur that lived approximately 215 to 208 million years ago during the Late Triassic period. This slender, agile predator was one of the earliest well-known dinosaurs and played a crucial role in our understanding of early dinosaur evolution. Coelophysis typically measured about 3 meters (10 feet) in length and weighed around 25kg (55 pounds), making it relatively small compared to later theropods. It had a long, narrow skull with sharp, serrated teeth, indicating a carnivorous diet. Coelophysis possessed hollow bones and a feature that would become characteristic of later theropods and birds. Its body was built for speed, with long, slender legs and a stiffened tail for balance, suggesting it was an active hunter. Fossil evidence, particularly from the Ghost Ranch site in New Mexico, indicates that Coelophysis may have lived in groups, providing some of the earliest evidence for social behavior in dinosaurs. This dinosaur likely preyed on small reptiles, early mammal-like creatures, and possibly even smaller members of its own species, as some fossils have been interpreted as showing evidence of cannibalism (though this remains debated).

Archaeopteryx

Archaeopteryx is a genus of dinosaur that lived approximately 150 -148 million years ago during the Late Jurassic period. It was about the size of a modern crow and represents for some one of the first birds, being a transitional animal between non-avian dinosaurs and modern birds. Archaeopteryx possessed a unique combination of reptilian and avian features: it had a full set of teeth, a long bony tail, and clawed fingers like its dinosaur ancestors, but also displayed distinctly bird-like traits such as feathers and a wishbone. The presence of flight feathers on its arms and tail suggests it was capable of at least some form of flight, though likely not as advanced as modern birds. Fossils of Archaeopteryx have been found in the Solnhofen limestone of southern Germany, with the first specimen discovered in 1861, just two years after the publication of Charles Darwin’s “On the Origin of Species.” This timing made Archaeopteryx an icon of evolution, as it provided strong support for Darwin’s theory. It inhabited a warm, tropical environment dotted with islands in a shallow sea, similar to today’s Caribbean. Based on its teeth and claws, Archaeopteryx was probably a predator, feeding on small animals such as insects, small mammals, and reptiles. Its ability for limited flight or gliding would have allowed it to move between trees or islands, possibly using its clawed fingers for climbing.

Oxalaia

Oxalaia was a genus of giant spinosaurid dinosaur that lived approximately 100.5 to 93.9 million years ago during the Late Cretaceous period. Among the largest theropods ever discovered, it reached impressive lengths of 12-14 meters (39-46 feet) and weighed between 5-7 tons, making it Brazil’s largest known predator. Known only from fragmentary skull remains that were tragically lost in a museum fire in 2018, its relationship to Spinosaurus remains debated, but it was clearly closely related. And like its close relative, it possessed a massive crocodilian-like skull measuring 1.35 meters (4.4 feet) long, equipped with over 40 sharp conical-oval teeth arranged in a rosette pattern, and a bite which was estimated to be 20 times more powerful than that of a modern wolf. It was also uniquely adapted for a semi-aquatic lifestyle, with nostrils positioned high on its snout and powerful hooked claws on its robust forelimbs. While it was primarily a fish-eater, evidence suggests it was an opportunistic predator that would also hunt small to medium-sized dinosaurs. It inhabited coastal regions with a mix of freshwater and brackish water, surrounded by humid tropical forests. The disappeared around 93.9 million years ago, and while the reason for its extinction is uncertain theories suggest either rising sea levels destroyed its preferred habitats or prolonged drought depleted its prey and freshwater sources.

Paraceratherium

Paraceratherium was a genus of giant hornless rhinoceros that lived approximately 34 to 23 million years ago during the Oligocene epoch. It was one of the largest land mammals to have ever existed, and reached shoulder heights of 4.8 meters (15.7 feet) and lengths of 7.4 meters (24.3 feet), weighing between 15 to 20 tonnes (33,000 to 44,000 pounds). Its massive skull, measuring 1.3 meters (4.3 feet) long, featured a distinctive retracted nasal incision suggesting it possessed either a prehensile upper lip or short trunk, as well as large tusk-like incisors. Unlike modern rhinoceroses, Paraceratherium was adapted for browsing tall vegetation, with a long neck and pillar-like legs that helped support its enormous bulk. As a browser, it fed primarily on soft leaves and shrubs, using its specialized front teeth and possible trunk to manipulate branches. It inhabited various environments across Eurasia, from arid deserts with scattered trees to subtropical forests. The genus became extinct around 23 million years ago, possibly due to a combination of factors including competition from newly arriving herbivores like gomphotheres, climate change, and the emergence of large predators in Asia.

Livyatan

Livyatan was a genus of macroraptorial sperm whale that lived approximately 9.9 to 5 million years ago, during the late Miocene and early Pliocene epochs. This colossal marine predator, named after the biblical sea monster Leviathan, was one of the largest and most formidable carnivores of its time. Adult Livyatan likely measured between 13.5 to 17.5 meters (44 to 57 feet) in length and could have weighed over 60 tons, rivaling the size of the megalodon shark, which lived during the same time period. Livyatan’s most distinctive feature was its enormous skull, which could exceed 3 meters (9.8 feet) in length, housing a set of fearsome teeth. These teeth, numbering 40 in total, were the largest of any known predatory animal (excluding tusks), reaching up to 36 cm (1.2 feet) in length and 10 cm (4 inches) in width. The teeth were deeply rooted and arranged in a way that created a powerful shearing bite, capable of dismembering large prey. Livyatan possessed a large spermaceti organ, suggesting advanced echolocation abilities that may have allowed it to detect prey from great distances. This organ, combined with its robust body, might have also been used as a battering ram when hunting. As a hypercarnivorous apex predator, Livyatan likely preyed on a variety of large marine animals, including whales, seals, and possibly even juvenile megalodons. Its ecological niche was similar to that of modern orcas, but on a much larger scale.

Megalania

Megalania, now scientifically known as Varanus priscus, was a giant monitor lizard that lived in Australia during the Pleistocene epoch, approximately 50,000 years ago. This enormous reptile was one of the largest known terrestrial lizards in history, with size estimates varying widely. Conservative estimates place adult Megalania at a length of at least 3.5 meters (11 feet) and a weight of 158 kg (348 lbs), comparable to a sea lion in length and a reindeer in weight. However, some studies suggest it could have reached lengths up to 7.9 meters (26 feet), rivaling the longest recorded anacondas, with a potential maximum weight of 2 tons, though most large specimens were likely around 575 kg (1200 lbs). Megalania possessed characteristics typical of monitor lizards, including razor-sharp, long, and recurved teeth for gripping prey, powerful legs, and sharp claws. As the closest living relative to the Komodo dragon, Megalania is believed to have been venomous, with venom acting as an anticoagulant to prevent blood clotting in its prey. This venomous bite, combined with its massive size and powerful build, made Megalania a formidable apex predator in Pleistocene Australia. Its hunting strategy likely mirrored that of modern Komodo dragons: biting prey, retreating, and allowing the venom to weaken the victim before finishing it off.