Which of Today’s Animals Lived Alongside Dinosaurs?

Discover some of the world’s oldest animals whose prehistoric ancestors walked (or swam) among the dinosaurs.

Mar 24, 2023By Donna Hobson
which animals lived alongside dinosaurs

Dinosaurs roamed our planet for more than 180 million years until an asteroid wiped them off the face of the Earth (probably). Whatever happened at this time destroyed most of the life on Earth; still, there was a range of marine animals and land-based vertebrates who survived. And some of them still walk alongside us today.

Discover the remnants of the prehistoric era with this list of fascinating creatures that managed to outlive the reptilian giants that once roamed Earth.


crocodile ancient reptile
Credit: Image by Pfüderi on Pixabay

Take a look at a crocodile, and it’s not hard to believe that these prehistoric-looking creatures roamed the Earth at the same time as the dinosaurs. These fearsome reptiles have called Earth home for an estimated 240 million years and the Cretaceous period housed a range of giant crocs, such as the Sarcosuchus, the world’s most enormous crocodile.

These 40-foot-long, carnivorous powerhouses continued to grow throughout their life, not attaining their full size until around ten years old when they could weigh up to 10 tons. Their name is Greek and means “flesh crocodile,” and these creatures would have lived on a diet that consisted mainly of fish. Their home - believe it or not - was the Sahara Desert; though it wasn’t a desert a hundred million years ago, it was a lush tropical paradise with rivers crisscrossing its land.

You won’t see any 40-foot crocodiles today, but these impressive creatures are still the largest reptiles on Earth, reaching heights of seven meters and a weight of up to 1000 kg. And these remarkable creatures can live for up to 70 years in the wild.

Sea Turtles

sea turtle floating
Credit: Image by Андрей Корман on Pixabay

Fossils show that sea turtles first swam through our oceans more than 164 million years ago, which means they would have lived alongside the dinosaurs for millions of years. Today’s green sea turtles evolved from the Archelon, the largest turtle ever existing, which lived during the late Cretaceous period.

These mighty sea creatures could reach over 13 feet and weigh up to 5000 lbs. Its shell possessed a similar appearance to that of today’s sea turtles, though it was more leathery in texture than hard. Its beak was hooked like a parrot, and the Archelon had powerful front teeth with crushing jaws that could drag prey through the water.

The green sea turtle is one of the largest species alive today, with a length of up to four feet. Their strong shell is known as a carapace and can vary in color from dark brown to olive, yellow, or black. They are called green turtles because of the green flesh beneath the shell, most likely colored by the large number of marine plants encompassing their diet.


shark swimming in ocean
Credit: Image by Taken on Pixabay

Sharks didn’t just live alongside the dinosaurs - they preceded them by around 200 million years! The majority of scientists believe that these fearsome predators have been swimming through our seas for more than 400 million years and have survived every major extinction event that has occurred since their creation.

The Megalodon was the largest fish that ever swam our oceans, and its bite could crush a car. In fact, its bite was so strong that it had a force at least three times greater than a T-Rex. These mighty sea creatures could weigh the equivalent of 30 of today’s great white sharks and reach lengths of up to 60 feet. Its mouth could open so wide that two adults could stand side by side in its mouth, and its banana-sized teeth could feast on whales and dolphins.

Megalodons required many large marine creatures to feed on in their warm sea waters. When Earth’s climate changed a couple of million years ago, most large marine species moved into cooler waters, and the Megalodon was left with insufficient food to survive.


jellyfish floating in the ocean
Credit: Image by Aernout Bouwman on Pixabay

The jellyfish is one of the most unique creatures on Earth, with an impressive set of characteristics that have allowed its species to exist for more than 600 million years. This makes them the oldest multicellular animals on Earth.

An ability that is critical for their survival is blending into the ocean with a body of 98% water. Jellyfish lack a heart, blood, or lungs and don’t have a brain. Instead, they have a nervous system that can detect light, chemicals, and vibrations in the water around them.

In addition, jellyfish can clone themselves if injured and even survive being cut in two. Each half can live by itself and regenerate any missing organs when this happens. And the immortal jellyfish can live forever (as long as a predator does not eat it)


bee pollen flower
Credit: Image by Myriams-Fotos on Pixabay

Today’s bees evolved from an ancient predatory wasp that lived around 120 million years ago. While today’s bees enjoy a flower-based diet, these carnivorous ancestors used their stings to paralyze other insects before transporting them back to their nests to feed developing offspring.

Whether or not bees died during the great extinction event is a heated debate between scientists; the most likely truth is that some species did die out, while others survived to evolve into the bees that we see populating our gardens today. Next time a bee flies around you, remember that dinosaurs had the same buzzing insect to contend with.

Still, bees are crucial to Earth. Around 75% of global crops depend on animal pollination, with a third of all your food depending on the work of pollinators such as bees. In order to produce one kilo of honey, bees must fly the equivalent distance of three times Earth’s circumference; the flavor of the honey is determined by the flower the bees take the nectar from.

These wonderful little creatures are the only social insect humans have partly domesticated. If you ever find one struggling, place it on a bee-friendly flower or mix a solution of 50:50 water and white sugar to give it a one-time energy boost.

Donna Hobson
By Donna Hobson

Donna believes that keeping a pet is the key to a happy life. Over the years, many creatures have passed through her home - Sooty the cat, Millie the rabbit, Stuart (Little) the guinea pig, and Trixie the tortoise, alongside her pet goldfish, Zippy, who lived to the grand old age of 24 years! She currently resides with her black kitten Jinx and an aquarium full of fish and snails to entrance them both. When she is not looking after her pets, Donna enjoys researching and writing the answers to all your pet-related wonders.