Top 18 Most Unusual Prehistoric Animals That Still Exist Today

Sturgeons inhabit rivers, lakes, and coastal waters in subtropical, temperate, and sub-Antarctic regions. Often referred to as "living fossils," their physical traits have changed little over the last 200 million years. Unfortunately, overfishing, pollution, and habitat destruction have put sturgeon species at serious risk, with some facing the threat of extinction.

Sturgeons are bottom-dwelling fish. They have wedge-shaped snouts that allow them to sift through soft muddy bottoms, using their sensitive barbels to detect small crustaceans and fish, which make up their diet. Without teeth, they can't capture larger prey.

Many sturgeon species spend most of their lives in the sea, but they return to large rivers during specific times to spawn. Some individuals perform this migration later in the season for reasons that remain unclear. Only a few species live exclusively in freshwater, and none are found in tropical areas or the Southern Hemisphere.

Like sharks and rays, sturgeons belong to the cartilaginous fish category. They have long, tubular bodies with five rows of bony plates (cartilage), tough, rough skin, and a split tail. Their small, wedge-shaped mouths have no teeth, and their long, pointed snouts are equipped with two pairs of hard barbels that act like a radar to help them locate food.

The largest salamander and amphibian species in the world, the Chinese giant salamander can grow up to 180 cm long. Part of the Cryptobranchidae family that dates back 170 million years, this unique creature is also critically endangered due to habitat loss, pollution, and overhunting, as it is considered a delicacy and is often used in traditional Chinese medicine.

This salamander has a large head, small eyes, and wrinkled black skin. It is one of only two surviving species in the Andrias genus, with the other being the Japanese giant salamander (Andrias japonicus), which is slightly smaller but very similar in appearance. The Chinese giant salamander feeds on insects, frogs, and fish. It has poor eyesight, relying on sensory nodules running along its body, from head to tail, to detect vibrations in its environment. Females lay 400-500 eggs in an underwater nest, which are guarded by the male until they hatch in 50-60 days. Adult salamanders typically weigh 25-30 kg and measure around 1.15 meters in length.

The Chinese giant salamander is known to make vocal sounds such as barking, grunting, hissing, or crying. Some of these noises resemble the cries of a baby, which is why it is referred to as 'baby fish' (娃娃鱼/鲵) in Chinese.

Discovered in 2000 in a Brazilian Amazon rainforest, the Martialis heureka ant immediately captured attention due to its unusual appearance. This blind, subterranean predator was uncovered by Christian Rabeling from the University of Texas (Austin). It belongs to a newly identified subfamily of ants, first discovered in 1923, and is a descendant of an ant species that evolved 120 million years ago.

Scientists are hopeful that this 3 mm-long insect, found in the Amazon rainforest, will provide valuable insights into the evolutionary process of ants.

While researching fungi in the Amazon last year, scientists unexpectedly stumbled upon this tiny insect, which they named “Martialis heureka.” This ant's distinct shape sets it apart from other ant species and is considered one of the oldest known living ants on Earth. Researchers used DNA samples from its forelegs to determine its ancient lineage.

Growing up to 4 meters (13 feet) in length, the goblin shark is a deep-sea species that may appear unattractive but is highly rare due to its distinct pink skin. Despite its eerie and unusual appearance, this ancient creature traces its origins back to prehistoric times, with its first ancestors believed to have lived 125 million years ago. Though large and intimidating, the goblin shark is harmless to humans.

This species feeds on a variety of deep-sea organisms, including squids, fish, crabs, and deep-water bacteria. Little is known about its history and reproductive behavior due to the rarity of encounters, and it poses no threat to humans. While scarce, the goblin shark is not currently considered endangered and is not classified as a threatened species by the IUCN.

This shark inhabits the deep waters, typically found near the ocean floor at depths of around 250 meters, with the deepest specimen captured at 1,300 meters. Goblin sharks are primarily caught off Japan, especially in areas between Tosa Bay and the Boso Peninsula. Their range spans the Indo-Pacific region, including offshore waters near South Africa, Australia, New Zealand, and California.

In the Atlantic, they have been spotted off the coast of French Guiana, the Gulf of Mexico, the eastern Bay of Biscay, off Madeira, and along the coasts of Portugal and northern Spain. Currently, around 45 goblin shark specimens are known worldwide.

The horseshoe crab (or sea crab) is an arthropod found mainly in shallow waters along sandy or muddy bottoms. It is considered the closest living relative to the legendary trilobite, and is one of the most famous living fossils, remaining unchanged for over 450 million years.

Horseshoe crabs are extremely poisonous, containing tetrodotoxins, which are highly dangerous. This toxin is primarily concentrated in the ovaries. During the breeding season, large amounts of the toxin are produced. The poison can spread to other parts of the body. If ingested, it rapidly enters the bloodstream, and within 30 minutes to 2 hours, symptoms such as numbness in the lips and tongue, abdominal pain, sweating, pupil dilation, excessive salivation, vomiting, low blood pressure, seizures, respiratory paralysis, coma, and even death can occur if the victim is not treated promptly.

Currently, there is no known antidote for tetrodotoxin poisoning. Notably, tetrodotoxins are heat-resistant, so even when cooked, the meat of the horseshoe crab remains toxic. Several other seafoods, like pufferfish and blue-ringed octopus, also contain dangerous toxins, yet their meat is considered delicious and highly nutritious.

The horseshoe crab's tail is triangular in shape, with three long sides extending to the end of the tail, and sharp saw-like spines at the tip. In contrast, the tail of a trilobite is round or oval, without spines. Horseshoe crabs are often found in pairs, with the male clinging to the female's back.

Alongside the platypus, the echidna is one of the last surviving mammals that still lay eggs. Scientific studies indicate that the echidna separated from the platypus around 48 to 19 million years ago. Although their common ancestors were aquatic creatures, echidnas have adapted well to terrestrial life. Due to their unusual appearance, they were named after the ‘Mother of Monsters’ from Greek mythology.

Echidnas are medium-sized, solitary creatures covered in coarse fur and spines. They resemble South American anteaters and other mammals such as hedgehogs. Their fur is usually black or brown, with rare albino specimens having pink eyes and white spines. They have a long, tapered snout that serves both as mouth and nose. Like the platypus, echidnas have electroreceptors, though while the platypus boasts 40,000 receptors on its bill, the long-snouted echidna has only around 2,000. Short-snouted echidnas, which live in drier environments, have fewer than 400 receptors at the tip of their snout.

Echidnas have short, strong limbs with large claws, making them excellent diggers. The claws on their hind legs are long and curved, enabling them to dig effectively. Their small mouths and toothless jaws allow them to tear apart soft wood, ant nests, and other food sources, using their long, sticky tongue to capture prey. Their ears are small openings on the sides of their heads, typically hidden beneath their spines. The outer ear consists of a large cartilage funnel located deep within the muscles. At a body temperature of 33°C, the echidna has the second lowest body temperature among mammals, just after the platypus.

Despite their unusual appearance, echidnas are actually excellent swimmers, as they are descendants of the platypus. While swimming, they expose their snouts and some spines, and they are known to enter the water to groom and bathe.

The tuatara is a rare species endemic to New Zealand, easily recognized by its row of spiny ridges along its back, especially in males. Despite their resemblance to modern reptiles and other lizards, tuataras have a body structure that has remained largely unchanged for over 200 million years. This makes them a key subject for scientists studying the evolution of lizards and snakes.

Tuataras are usually grey or greenish-brown, growing up to 80 cm long from snout to tail and weighing up to 1.3 kg. Their back is adorned with a distinctive row of spines, particularly prominent in males. Their teeth, consisting of two upper rows that overlap a single row on the lower jaw, are unique among reptiles. Though lacking external ears, tuataras are capable of hearing. They also possess a “third eye” on top of their head, which can detect light, but this eye gradually fades as they mature. Their skeletal structure shows unique traits inherited from their fish ancestors.

Tuatara lizards are slow-moving and reproduce at an exceptionally slow rate. In 2008, they were observed breeding on New Zealand’s main island for the first time in 200 years. Tuataras are the only species able to survive in temperatures ranging from 10°C to 15.5°C, feeding on large insects and living in burrows they dig themselves. If you wish to maintain a healthy tuatara, it’s crucial to replicate these strict environmental conditions. However, owning one as a pet is nearly impossible due to their specific needs.

The frilled shark, a living fossil, inhabits deep waters ranging from 50 to 200 meters (160 to 660 feet) in the Atlantic and Pacific Oceans. This ancient shark species dates back at least to the late Cretaceous period (95 million years ago) and possibly as far as the late Jurassic (150 million years ago).

Scientists once believed the frilled shark slithered through the water like an eel. However, according to the ReefQuest Shark Research Center, its body is long and slender with a massive liver filled with low-density blood and hydrocarbons, enabling it to navigate the depths with ease.

Its diet mainly consists of squid, although it also preys on various fish species, including other sharks. Uniquely, the frilled shark’s mouth is positioned on the top of its head rather than underneath, as is typical of most sharks, and it possesses small, three-cornered teeth in both jaws. The teeth are spaced far apart, and its long jaw contrasts with the short lower jaw of most sharks. The frilled shark is perfectly adapted to life on the ocean floor. Its reduced skeleton and massive liver, packed with low-density lipids, help it maintain its position in the water effortlessly.

To survive in deep ocean environments, its bones are calcified, and its liver grows fat-rich tissue, which allows it to remain almost motionless in the water. The frilled shark, however, is vulnerable to predation by other more aggressive shark species.

The alligator snapping turtle, primarily found in the southeastern United States, is one of only two surviving species in the Chelydridae family, a prehistoric turtle lineage that dates back to the Maastrichtian stage (about 72–66 million years ago) of the late Cretaceous period. Weighing up to 400 pounds (180 kg), it holds the title of the heaviest freshwater turtle in the world.

This turtle is commonly found in the waters of southern North America, ranging from eastern Texas to Florida, and extending as far north as southeastern Kansas, Missouri, southeastern Iowa, western Illinois, western Kentucky, and western Tennessee. Due to the exotic pet trade and other factors, the species has also spread to Asia and Europe, with a research and breeding center located in Japan.

Characterized by a large head, powerful jaws, and sharp, pointed ridges, the alligator snapping turtle can exert a bite force of 480 kg/inch², strong enough to crush the shells of other turtles for food. Its shell features three rows of spiny protrusions, which house an abundance of sensitive nerve endings. Though unverified reports suggest a 183 kg specimen in Kansas in 1937, the largest confirmed specimen remains controversial.

This species reaches sexual maturity around 12 years of age. Mating occurs in early spring, and females build nests, laying 10 to 50 eggs after approximately two months. The sex of the hatchlings is determined by the temperature of the nest. Incubation lasts from 100 to 140 days, with hatching occurring in early fall. The turtle's lifespan remains uncertain, with estimates ranging from 80 to 120 years in the wild, but it is believed to live up to 200 years. In captivity, they typically live between 20 and 70 years.

The coelacanth, native to the coasts of the Indian Ocean and Indonesia, is one of only two remaining species of the Latimeria genus. Once believed to be extinct, it was rediscovered in 1938. Closely related to lungfish, reptiles, and mammals, coelacanths are more distantly related to typical bony fish. The first coelacanth fossils date back to the middle Devonian period, around 410 million years ago, and prehistoric coelacanths thrived in various aquatic environments during the late Paleozoic and Mesozoic eras.

Coelacanths typically weigh around 80 kg and can grow up to 2 meters in length. Scientists estimate that they can live up to 60 years. These fish dwell at depths of around 700 meters below sea level. They are the only living creatures known to have a functional joint in their skull, which nearly separates the front and rear portions of the skull. This unique joint may assist them in consuming large prey. Coelacanths also produce a slimy substance on their scales and their bodies constantly exude oil, which serves as a laxative and makes them nearly impossible to eat unless dried and salted. The rough scales of the coelacanth are even used as sandpaper by the people of the Comoros region.

The coelacanth's eyes are highly sensitive and possess a tapetum lucidum, a reflective layer similar to that found in cat eyes. Due to the high sensitivity of their eyes, coelacanths are almost impossible to catch during daylight or on full moon nights.

These opportunistic predators hunt cephalopods, eels, small sharks, and other creatures found in their deep-sea habitats, often near submerged rock walls and underwater volcano slopes. Coelacanths are known for their unique swimming technique, where they dive head-first, then back up and flip onto their bellies to locate prey, likely using sensory organs located on their snout. Scientists believe their success may be due to their ability to drastically slow their metabolism, diving to depths with less activity and minimizing nutrient needs, almost like a form of hibernation.

The nautilus, a marine mollusk, inhabits the steep slopes of coral reefs in the Indian Ocean and the western and central Pacific. Fossil records indicate that this species has existed for over 500 million years, surviving multiple mass extinctions and significant environmental changes. Unfortunately, it is now facing the risk of extinction due to human activities such as overfishing.

This fascinating creature has 90 tentacles around its mouth and head, with two thickened ones that it uses to seal its shell for protection. When hunting, it fully extends all of its tentacles, but when resting, it retracts most, leaving only a few to stay alert. The nautilus also possesses a unique water-squirting funnel formed by two muscle segments. It moves along the ocean floor by crawling on its tentacles, often camouflaging itself in coral and rocks. After storms, it emerges in groups to the surface to feed on shrimp and small fish before retreating back to the depths.

Despite its hard outer shell, the nautilus is closely related to squids. Unlike squids, which have evolved to lose their external shell, the nautilus has retained this ancient feature. In Vietnam, the nautilus is found in the waters of Khanh Hoa and Ba Ria – Vung Tau, though it is rare and overharvested for ornamental use, making it susceptible to extinction. The patterns on its shell can even help scientists estimate the age of the Earth.

Found in oceans around the world, from the surface to the deep seabed, jellyfish have likely existed for over 700 million years, making them one of the oldest creatures on Earth. Despite their long history, jellyfish populations are still expanding, though some species are now at risk of extinction.

Jellyfish have existed since the Cambrian period and share similar structural features with hydras. However, jellyfish are adapted for a life of mobility in the ocean. They move by contracting their bell, forcing water through their mouth and propelling themselves forward. Some jellyfish tentacles can cause stinging sensations and even burns to human skin. Jellyfish lack a brain, heart, and bones.

These creatures are found in all the world's oceans and even in some freshwater lakes and ponds. The size of a jellyfish's body can range from being as small as a fingertip or the eraser on a pencil, but some can have body diameters up to 2.5 meters, with tentacles stretching as long as 60 meters—about the length of two blue whales.

Each of a jellyfish's tentacles contains thousands of cells called cnidoblasts. Inside these cells are nematocysts, which are coiled, needle-like structures containing venom. When prey becomes entangled in a jellyfish's tentacles, the pressure within the nematocysts causes the needles to straighten, injecting venom into the prey, much like a barb on a fishing hook.

Widespread across southern Africa, the elephant shrew is a small four-legged mammal resembling rodents or marsupials like the opossum, but it is believed to be closely related to elephants, as its name suggests. Fossil records indicate that the earliest ancestors of this peculiar creature lived during the Paleogene period, around 66 to 23 million years ago.

Several known fossil species all originated from Africa. They differ from the similar-looking Leptictida order. There was a significant diversification of elephant shrew species during the Paleogene, some of which, such as Myohyrax, resembled the odd-toed ungulates so much that they were initially classified with them, while others, like Mylomygale, were closer to rodents. These unusual forms all went extinct by the Pleistocene epoch. Although elephant shrews have been classified into various groups based on superficial physical traits, significant morphological and molecular evidence today suggests they belong to the Afrotheria group, likely closely related to the base of Paenungulata.

Elephant shrews primarily feed on insects, spiders, millipedes, and earthworms. They use their noses to locate prey and their tongues to stuff small food items into their mouths, much like anteaters. Hunting larger prey can be challenging; when an elephant shrew struggles with an earthworm, it first holds the prey down with its front legs. Then, tilting its head sideways, it chews each piece using its molars, much like a dog chewing a bone. This process is clumsy, and many small pieces of the worm fall to the ground, only to be scooped up with its tongue. Some elephant shrew species also consume small amounts of plant matter, especially young leaves, seeds, and small fruits.

Surprisingly, large water birds with long, broad beaks, like the pelican, are living fossils. Fossil records suggest that pelicans have existed for at least 30 million years. The earliest pelican fossils, found in Oligocene deposits in France, closely resemble the shape of modern pelicans.

The pelican (scientific name: Pelecanus) belongs to the family Pelecanidae in the order Pelecaniformes. These birds are distinguished by their long beaks and large throat pouches, which they use to catch prey and drain water from their catch before swallowing it. Most pelicans have light-colored plumage, with exceptions being the brown pelican and the Peruvian pelican. The beaks and bare facial pouches of all pelican species become brightly colored during the breeding season.

The eight living species of pelicans have a widespread distribution across the globe, ranging from tropical to temperate regions, although they are absent from inland South America, the polar regions, and open oceans. Fossil evidence of pelicans dates back at least 30 million years, with beak remnants remarkably similar to those of modern species found in Oligocene strata in France.

The relationship between pelicans and humans has been controversial. These birds have been persecuted due to competition for commercial and recreational fish resources. They have also faced habitat destruction, disturbances, and environmental pollution, leading to three species being listed for conservation. Pelicans also hold significant cultural meaning in mythology, Christianity, and heraldry.

Unlike the hedgehog and many other species on this list, crocodiles share a striking resemblance to ancient dinosaurs. This group, which includes the African crocodile, American crocodile, saltwater crocodile, Indian crocodile, and false gharial, emerged around 250 million years ago during the early Triassic period, with modern members still exhibiting many traits similar to their prehistoric ancestors.

In addition to their massive size, making them the largest freshwater predators in the world, the African crocodile instills fear in humans due to its razor-sharp teeth and immense biting force. Any prey within their sights stands little chance of escaping death, including humans. Victims either drown in the water or are torn apart by the crocodile's sharp jaws. While exact statistics on human fatalities are unavailable, estimates suggest that hundreds of people may fall victim to these deadly creatures each year.

Scientifically named Triops longicaudatus, the long-tailed tadpole shrimp is a small, freshwater crustacean that closely resembles a miniature horseshoe crab. It is often referred to as a 'living fossil' because its prehistoric form has remained virtually unchanged for over 70 million years. Its appearance today is strikingly similar to that of its ancient ancestors, which roamed Earth around 220 million years ago.

Although it thrives in freshwater, many species of tadpole shrimp can also live in dry, desert environments where rainfall is scarce. These ancient creatures are easily identifiable by their horseshoe crab-like head, long segmented tail, and two long antennae pointing backward.

In captivity, long-tailed tadpole shrimp typically grow up to 6 cm long, though in the wild they can reach 11 cm. On top of their heads, they have a pair of compound eyes along with a 'third eye,' which gives them the name 'triops' (meaning 'three eyes' in Ancient Greek). Despite only living in freshwater, many species of tadpole shrimp thrive in arid deserts thanks to a remarkable survival strategy. The larvae live in temporary pools formed by rare desert storms. When these pools dry up, the adult shrimp die, but their eggs can survive in the dry heat for over 15 years. When it rains, the eggs hatch.

Within just 24 hours of hatching, the shrimp resemble miniature versions of the adults. They mature in 2-3 weeks, reproduce, and then die before the water evaporates under the scorching sun. Due to their impressive reproductive abilities, tadpole shrimp eggs are sold as 'kits' for enthusiasts to hatch and raise them in home aquariums.

The hagfish is a species with a very distinctive jaw. While they are famous for their bizarre ability to burrow their mouths into other fish to suck out blood, only a few of the 38 known species have this bloodsucking trait. The oldest fossils of hagfish were found in South Africa and date back 360 million years.

Characteristics of the hagfish:

• Hagfish have long bodies, with an average adult reaching up to 90 cm in length.
• They possess smooth, slimy skin, and their bodies lack bones, instead having cartilage running the length of their bodies.
• Color-wise, they are typically a mix of brownish-white or dark gray on their backs and bellies.
• Additionally, hagfish are equipped with numerous slime glands along their bodies.
• When in seawater, they can secrete large amounts of slime in a short period, which helps them defend themselves and escape predators.

Hagfish typically reside on the ocean floor, at depths ranging from 1,000 to 1,500 meters below sea level. They prefer to burrow into the mud or sand, and due to the lack of sunlight at these depths, their vision is quite limited. However, this is not a major issue, as they rely on their keen sense of smell to navigate and locate prey.

Hagfish are nocturnal feeders, preferring small crustaceans, shrimp, juvenile fish, and other tiny creatures that live on the ocean floor. Marine experts classify them as parasitic fish, meaning they can also feed by attaching to other fish to absorb nutrients. Additionally, hagfish can survive for months without food, as they can go without eating for extended periods.

Native to North America and northeastern Siberia, the Sandhill Crane is a large bird weighing over 10 pounds (4.5 kg). A 10-million-year-old fossil discovered in Nebraska was believed to belong to a species similar to the Canadian Crane, though scientists are uncertain if they are the same. However, fossils of another crane species dated to 2.5 million years ago have been definitively identified as belonging to the Sandhill Crane.

Adult Sandhill Cranes typically have a grayish-black body with a reddish crown, a long and slender neck, short tail feathers, and a straight, long bill. Their average weight ranges from 3 to 6.5 kg, with a body height of 80-120 cm and a wingspan of about 1.2-1.5 meters. These cranes can live up to 20 years. Sandhill Cranes are omnivorous and thrive in freshwater habitats. Their diet consists primarily of small mammals, worms, snakes, insects, and grains. They can also dig up plant roots to eat, which can sometimes affect local crops.

At dawn, thousands of cranes leave shallow wetlands and embark on a 80-160 km journey to feed on harvested rice fields. There, they spend the day searching for fallen rice grains before returning to their roosting areas in the evening.

During the breeding season, pairs of cranes engage in dances, extending their wings, flapping them, and calling out to attract mates. These dances are more frequent in the spring, during the mating season, but occur year-round to strengthen the bond between pairs. Their nests are built on the ground near areas with abundant food sources, with nests measuring approximately 75-100 cm in diameter and 10-15 cm in height.

Sandhill Cranes are migratory in winter and return in summer to breed. The smaller subspecies, including the Lesser Sandhill Crane and Canadian Sandhill Crane, follow this migratory pattern, while other subspecies remain year-round in southeastern USA and Cuba.