Animals Wildlife 16 Animals That Are Living Fossils By Bryan Nelson Writer SUNY Oswego University of Houston Bryan Nelson is a science writer and award-winning documentary filmmaker with over a decade of experience covering technology, astronomy, medicine, and more. our editorial process Twitter Twitter Bryan Nelson Updated September 11, 2020 Jacek Fulawka / Shutterstock Share Twitter Pinterest Email Animals Wildlife Pets Animal Rights Endangered Species A living fossil is an organism that has retained the same form over millions of years, has few or no living relatives, and represents a sole surviving lineage from an epoch long past. Many living fossils alive today, like the pig-nosed turtle and the goblin shark, have unusual traits that make them seem otherworldly. They have often survived several mass extinctions, and many scientists consider them to be a rare glimpse into how life on Earth was long ago. Here are some examples of these amazing creatures. 1 of 16 Komodo Dragon GUDKOV ANDREY / Shutterstock Most people would agree that no other lizard in the world looks more prehistoric than a komodo dragon. They can be traced to the genus Varanus which dates back about 40 million years. First seen in Asia, komodo dragons later migrated to Australia, where they grew into their current massive size. They are the largest and heaviest lizards in the world. While they are famously named after the Indonesian island of Komodo, their ancestors first appeared in Australia — some 100 million years ago. 2 of 16 Sandhill Crane Haricharan / Flickr / CC BY-ND 2.0 While many birds can trace their ancestry back to dinosaurs, fossils show that the sandhill crane itself dates back 10 million years. Ancient sandhill cranes varied in size compared to today’s cranes. There are now several subspecies of sandhill cranes that live in North America — some of which are listed as endangered. Sandhill cranes are popular with bird enthusiasts because of their annual migration. Hundreds of thousands migrate from Mexico and the southern U.S. all the way up to the Arctic. 3 of 16 Aardvark Kelsey Green / Shutterstock Aardvarks are nocturnal, burrowing animals and the only living species in the order Tubulidentata. Genetically, the animal can be considered a living fossil because of the ancient arrangement of its chromosomes. Aardvark fossils dating back five million years have been found in South Africa. Aardvarks are part of the group of animals that includes elephants, hyenas, and golden moles. 4 of 16 Red Panda Hung Chung Chih / Shutterstock Hailing from the temperate forests of the Himalayas and the mountains of China, these adorable creatures are the only surviving members of the family Ailuridae. In 2020, scientists discovered that there are two distinct species of red pandas: the Himalayan red panda and the Chinese red panda. Relatives of the red panda lived between five and 12 million years ago. Despite their shared taste for bamboo, red pandas are not closely related to giant pandas. 5 of 16 Tuatara BeautifulBlossoms / Shutterstock They may look like lizards, but tuataras are actually part of a different order called Sphenodontia. Only two species of tuatara exist today, and they have much the same form as their ancient ancestors that thrived 200 million years ago. There are tuataras alive today that are well over 100 years old, and some experts believe they could live to be more than 200 years old under the right conditions. Unfortunately, these amazing creatures can only be found only on small islands off the coast of New Zealand. 6 of 16 Nautilus kikujungboy CC / Shutterstock The nautilus represents the only living member of the subclass Nautiloidea. Nautiluses are cephalopods that retain an outer shell unlike other distantly related animals such as squid and octopus. Their beautiful shells have inspired many artists over the centuries, and they are also among the finest natural examples of a logarithmic spiral or the golden ratio. Because of their shells, the fossils of nautiluses are easier to come by than remains of other cephalopods, and fossil hunters have discovered ancient shells dating back at least 500 million years. 7 of 16 Purple Frog David V. Raju / Wikimedia Commons / CC BY-SA 4.0 Discovered as recently as 2003, this living fossil is also known as the pig-nosed frog due to its shapely snout. A rare and burrowing species, the purple frog is difficult to find as it is only observed out in the open for short periods of time. Though found in India, the purple frog’s closest living relatives can only be observed on the Seychelles islands, meaning these frogs have been around for approximately 120 million years, when India, Madagascar and Seychelles were connected as a single land mass. Purple frogs are listed as endangered and their population is decreasing. 8 of 16 Platypus Photo: worldswildlifewonders/Shutterstock With a snout like a duck, and a hairy body like a mammal, it’s hard to find a more unique animal than the egg-laying platypus. They have 10 sex chromosomes instead of two (X and Y) like most other mammals, and are one of the most venomous mammals in the world. It's no surprise that they are the sole living representative of the family Ornithorhynchidae. Fossils of platypus-like mammals date as far back as 100 to 146 million years ago, making them extremely valuable for studying mammalian evolution. 9 of 16 Hagfish NOAA / Wikimedia Commons / Public Domain These animals may look like slimy eels, but many experts don't consider them to be fish. In fact, some taxonomists are hesitant to consider them vertebrates, since they are the only living animals that have a skull but not a vertebral column. From an evolutionary point of view, they can be recognized from fossils that date back to 330 million years ago, and they represent a crucial living link between vertebrates and invertebrates. One descriptor that is not a misnomer is slimy. In fact, hagfish secrete a gooey slime when handled or threatened, which in the wild helps them to escape from predators. 10 of 16 Hoatzin Corine06 / Flickr / CC BY-SA 2.0 These odd-looking, pheasant-sized birds are arguably the most debated living birds because their evolutionary tree is missing so many branches. The hoatzin is the only member of its family (Opisthocomidae), though some taxonomists also place them in their own order. They retain some characteristics that are not found in any other birds. For instance, as chicks they still retain claws on the ends of their wings, which aid them in climbing and clinging to trees. Evaluation of fossils suggests that hoatzin may have existed as long as 34 million years ago. Regardless of how they fit into the evolutionary picture, they are stunning ancient animals. 11 of 16 Koala Weili Li / Getty Images These Australian marsupials are an icon for wildlife across the globe — a familiarity that overshadows their uniqueness. Though often referred to as bears, they are not related to bears at all. In fact, they are members of the family Phascolarctidae. As marsupials, they carry their young in a pouch. Fossils of koalas are rare, but these marsupials have likely been around for at least 30 to 40 million years. 12 of 16 Pig-nosed Turtle pitcharee / Shutterstock As the only living member of the family Carettochelyidae, the pig-nosed turtle is one of a kind — and not just because of its distinctive snout. Unlike most freshwater turtles, these guys have flippers which more closely resemble those of marine turtles, making them almost entirely aquatic. This unique turtle, which was around over 140 million years ago, currently occupies a small area of southern Australia and northern New Guinea. 13 of 16 Horseshoe Crab Jarous / Shutterstock Despite their name, horseshoe crabs are not crabs at all. In fact, they aren't even crustaceans, being more closely related to arachnids like spiders than to anything else. But for years, there was doubt about their relationship to arachnids. In 2019, a team of evolutionary biologists from the University of Wisconsin-Madison analyzed a collection of genetic data and confirmed that horseshoe crabs are in fact related to arachnids. Horseshoe crabs have been around for about 450 million years. They are truly alien-looking — they even have blue blood. Horseshoe crabs also have a unique immune system, and studying them has led to breakthroughs in cancer research and spinal meningitis treatments. 14 of 16 Goblin Shark Dianne Bray / Museum Victoria / Wikimedia Commons / CC A 3.0 The frightening looking goblin shark is an ancient deep sea shark thought to be closely related to the extinct shark genus Scapanorhynchus, which existed as long as 66 million years ago. These sharks, which are known for their unusually long snouts, can grow to over 12 feet in length, but are rarely seen outside of their deep underwater habitat. Goblin sharks are part of the Lamniformes order of mackerel sharks which also include basking sharks and great white sharks. 15 of 16 Elephant Shrew trabantos / Shutterstock Their common name suggests otherwise, but these odd-nosed animals are not related to shrews. Elephant shrews share a relationship to other distant and distinct animals such as aardvarks, elephants, and even manatees. Believed to exist as long as 45 million years ago, the elephant shrew gets its name from its long movable snout. A 2020 observation of the Somali elephant-shrew in Africa has encouraged researchers who thought the species may have been lost. 16 of 16 Crocodiles Nneka Mckay / EyeEm / Getty Images No other animal deserves the title of living dinosaur like the crocodile. These beasts have exhibited the same body form since dinosaurs walked the Earth, surviving the mass extinctions that wiped out nearly all of their mammoth brethren. Crocodiles are also the closest living relatives of birds, representing a long-diverged connection between birds and reptiles. A common ancestor of both species existed over 240 million years ago.