Believe it or not, there are animals on Earth today that have been around for hundreds of millions of years, predating even the mighty T-Rex.
These living fossils offer a fascinating glimpse into the ancient past, revealing secrets of evolution and survival. Here’s 13 oldest animal species on earth that most people don’t realize have been around since the dawn of time, and are still thriving.
1. Sponges (Porifera)
These simple, aquatic animals are the oldest multicellular organisms on Earth, dating back over 580 million years. They lack true tissues and organs but possess a filtering system for feeding.(ref)
2. Brachiopods (Brachiopoda)
These marine animals with hinged shells resemble clams but are not closely related. They have a rich fossil record, spanning at least 550 million years, and are known for their diversity in the Paleozoic Era.(ref)
3. Comb Jellies (Ctenophora)
These gelatinous, iridescent creatures are among the earliest branching animal lineages. They propel themselves through the water using rows of cilia and have been capturing prey with sticky tentacles for at least 500 million years.(ref)
4. Jellyfish (Medusozoa)
These free-swimming, bell-shaped animals are known for their stinging tentacles and diverse life cycles. They are ancient creatures with a fossil record extending over 500 million years.(ref)
5. Nautilus (Nautilidae)
These cephalopods with chambered shells are often called “living fossils” due to their resemblance to ancient ammonites. They have survived relatively unchanged for over 400 million years.(ref)
6. Horseshoe Crabs (Limulidae)
These arthropods with hard exoskeletons are more closely related to spiders and scorpions than to true crabs. Their lineage dates back over 544 million years, making them one of the oldest living arthropod groups.(ref)
7. Velvet Worms (Onychophora)
These caterpillar-like animals with soft bodies and numerous legs are considered a “missing link” between arthropods and annelids. They have a long evolutionary history, with fossils dating back over 520 million years.(ref)
8. Lungfish (Dipnoi)
These unique fish possess both gills and lungs, allowing them to breathe air and survive in oxygen-depleted waters. They represent an ancient lineage with a fossil record extending over 410 million years.(ref)
9. Coelacanth (Coelacanthiformes)
Coelacanths are ancient fish once thought to be extinct, known as “living fossils.” They possess unique lobed fins and a lineage dating back over 400 million years.(ref)
10. Lamprey (Petromyzontiformes)
Lampreys are eel-like jawless fish with a sucker-like mouth lined with teeth. They are parasitic and have a long evolutionary history, with fossils dating back over 360 million years.(ref)
11. Tadpole Shrimp (Triops)
Tadpole shrimp are small crustaceans with a distinctive shield-like carapace and a long, forked tail. They are considered to have a lineage dating back over 25 million years.(ref)
12. Martialis Heureka Ant (Martialis huereka)
This ant species, discovered in 2003, is considered one of the oldest ant lineages.(ref) It is a subterranean predator with primitive features, providing insights into early ant evolution.
13. Bird Louse (Menoponidae)
Bird lice are small, wingless insects that parasitize birds. They have co-evolved with their avian hosts for millions of years. Ornithologists estimate that parasitic lice first emerged between 90 and 100 million years ago,(ref) but didn’t begin to diversify until 66 million years ago, around the time when early birds and feathered dinosaurs were evolving.
These 13 resilient species that have persevered through eons of environmental change. By understanding and appreciating these species, we gain a deeper respect for the delicate balance of our planet and the importance of preserving its rich biodiversity for generations to come.
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Davin is a jack-of-all-trades but has professional training and experience in various home and garden subjects. He leans on other experts when needed and edits and fact-checks all articles.