Lake Sturgeon

Seven Aquarium Animals That Lived Among the Dinosaurs

Life today might look a lot different than it did when some of your favorite giant lizards roamed the Earth (between 245 and 66 million years ago). But you might be surprised to learn that a lot of animals on the planet today have prehistoric ties to the time of the dinosaurs. Here are just seven of those animals you can find at the Aquarium. 

1) Lake Sturgeon 

Sturgeons have remained virtually unchanged for more than 100 million years. Unlike some of the most famous reptilian predators with which they once shared the Earth, Lake Sturgeon do not have typical teeth but instead have wide crushing plates they use to crush clams, mussels and crustaceans found on the lake floor. Once plentiful in the Tennessee River, Lake Sturgeon populations declined in the 1900s rapidly due to habitat loss and overharvesting. (Learn how we’re working with partners to bring them back!)

2) Paddlefish

Paddlefish appear in fossil records dating back almost 100 million years. When they were first discovered and described, they were mistakenly identified as sharks – mostly due to common characteristics, such as a skeleton primarily composed of cartilage. While they are not sharks, they do possess a similar electrosensory system in their rostrum (paddle-shaped snout) and about their head. This is used to detect weak electrical fields created by dense populations of zooplankton and to help them avoid obstacles.

3) Alligator Gar

Alligator Gar
This fish can be traced back to the Early Cretaceous Period (over 100 million years ago.) Nowadays, the Alligator Gar is one of the largest freshwater fish species in North America – growing up to 10 feet long in the wild! These ambush predators are armed with a double row of sharp teeth as well as thick scales, both of which led to its reptilian-like common name. 

4) Crocodilians

Dwarf African Crocodile
Nearly 100 million years ago, the world was full of dinosaurs, but their crocodilian cousins were also lurking near prehistoric swamps. While the giant dino-lizards have since died out, according to IUCN 24 crocodilian species still exist today – including alligators, caimans and crocodiles.

5) Sharks

Sand Tiger Shark
Sharks are some of Earth’s oldest lifeforms and are thought to predate the dinosaurs. The modern sharks we see today originated about 200 million years ago and have since diversified into close to  500 species. Fossilized shark teeth can tell us a lot of information about prehistoric sharks, like where they lived, what they ate, and how big they were. It’s believed that sharks avoided mass extinction by diving deeper in the oceans. Some of the oldest sharks alive today are the Goblin Shark and Frilled Shark. 

6) Horseshoe Crab

horseshoe crab
Originating more than 300 million years ago, these marine arthropods are called living fossils. Often mistaken for crustaceans (like crabs, lobsters, or shrimp) they are actually more closely related to arachnids (like spiders). 

7) Ctenophores

comb jelly
Recent studies estimate that ctenophores, commonly known as Comb Jellies, appeared at least 500 million years ago. While they have a jelly-like gelatinous body, they are not truly jellyfish, which are classified as the cnidarians. They are known for their “combs,” which they use as paddles to swim through the water. Some genetic scientists argue that ctenophores were the first known animals on Earth, instead of the Sea Sponge, which was previously purported as the oldest. Fun fact: Ancient Comb Jellies may have had hard skeletal spines and lacked the tentacles of modern comb jellies.

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