The top 10 oldest living animal species on earth are those species that are not extinct. They might have changed their physical structure and behavior over time in terms of size, like the crocodile they are now just smaller in size from millions of years ago. These animals can thus be called Living fossils.
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 era long past. Also, nearly all of these species on the list are known as “living fossils” because they have not evolved too far from their original forms.
These animals have survived several mass extinctions, and many scientists consider them to be a rare glimpse into how life on Earth was long ago.
Most of the Earth’s history has been uncovered through research because of the fossil record. Because of this record research, scientists have been able to piece together the evolutionary tree as well as the evolution of the Earth itself. All of the species on this list have ancestors whose fossils date back hundreds of million years ago.
Here are the top 10 oldest living animal species on earth.
10. Platypus
Platypus one of the most venomous mammals in the world. 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. Protoanguilla Palau
Protoanguilla Palau is a new species of small, eel-like fish discovered from a fringing-reef cave in the western Pacific Ocean in the Republic of Palau. It’s so unlike other eel-like critters that it forced biologists to create a whole new family to describe it: Protoanguillidae.
Research and tests based on numerous osteological characters and whole mitogenome sequences suggest that P. Palau is sister to all other living Anguilliformes, the true eels. If this relationship is correct then the split between these lineages dates approximately to the early, 200 million years ago.
8. Crocodile
These dangerous predators have exhibited the same body form since dinosaurs. Crocodiles are also the closest living relatives of birds, representing a long-diverse connection between birds and reptiles. A common ancestor of both species existed over 240 million years ago.
7 . Cockroach
These insects can survive for weeks without their heads and even withstand the fallout following a nuclear blast. Cockroaches are also an especially long-surviving animal. Roaches have thrived on Earth for some 320 million years.
6. Hagfish
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.
5. Elephant Shark
The elephant shark is not actually a shark, but a type of cartilaginous fish. It belongs to a group of fish called ratfish, which diverged from sharks about 400 million years ago. scientists mapped the genome of this creature, revealing DNA that’s barely changed for nearly 420 million years.
4. Horseshoe Crabs
These weird-looking, ancient creatures are nearly identical to their oldest ancestors found in the fossil records. In 2008, researchers found 445 million-year-old horseshoe crab fossils, which are about 100 million years older than any other horseshoe crab fossils ever discovered. Despite their name, horseshoe crabs are not crabs at all. In fact, more closely related to arachnids like spiders than to anything else.
3. Jellyfish
Jellyfish are the oldest multi-organ animal in the world and have existed in some form for at least 500 million years. The oldest known definitive jellyfish fossil dates back to 500 million years. Back in 2007, researchers discovered fossil snapshots of one of the oldest jellyfish ever. Once part of the ocean floor, the state of Utah has revealed four different types of jellyfish dating to more than 500 million years ago.
2. Comb Jellies
Comb Jelly is also known as the ctenophores first emerged 700 million years ago. Biologists say these are among the oldest known animals. There is always been a big debate among scientists on which is the oldest living fossil between the comb jellies and sponge.
1. Sponge
Most people don’t realize that a sponge is a living organism or animal. They are the longest existing creatures on Earth. The oldest evidence of a sea sponge found was a fossil discovered in 2014 in a 760-million-year-old rock discovered in Namibia.