What Animals Alive Today Lived with Dinosaurs? 15 Surprising [Prehistoric] Species!

What Animals Alive Today Lived With Dinosaurs? It’s fascinating to think that sea turtles, horseshoe crabs, tuatara, lobsters, and cockroaches, among other species, have existed for millions of years, evolving and adapting through the eons. This leads to an intriguing question: Which animals living today coexisted with dinosaurs, and how have they managed to survive until now?

What Animals Alive Today Lived with Dinosaurs?

The animals that lived during the dinosaur era and are still alive today include sea turtles, horseshoe crabs, tuatara, lobsters, cockroaches, duck-billed platypus, sea stars, sharks, bees, snakes, crocodiles, salamanders, frogs, chickens, and ostriches.

Key Takeaways

• Evidence suggests Sauropods like Brontosaurus, Apatosaurus, and Diplodocus created supersonic cracks with their tails.
• Some current animals such as sea turtles, horseshoe crabs, and cockroaches coexisted with dinosaurs millions of years ago.
• Despite the common belief, the Brontosaurus was unique enough to warrant its own classification separate from other dinosaurs.
• Sharks, one of the first vertebrates, have been around for over 400 million years since the Late Ordovician Period.
• Crocodilians, including Neosuchia, Notosuchia, and Protosuchia, appeared on earth 95 million years ago during the Late Cretaceous Period.
• Contrary to expectation, the T. Rex’s closest living relatives today are birds like ostriches and chickens, not crocodiles.

Dinosaurs, a captivating group that roamed the Earth millions of years ago, shared their world with several animals that persist today. Crocodiles and Alligators, creatures that mirror their prehistoric ancestors, inhabited the same era as dinosaurs. Sharks, representing another ancient species, existed in the oceans during the reign of the dinosaurs.

Komodo Dragons, recognized relatively recently by science, descend from ancestors living in the dinosaur era. A similar evolutionary lineage belongs to Tuatara, unique reptiles exclusive to New Zealand. Lungfish, a group possessing remarkable adaptability for both water and land, exhibit little change over their lengthy existence.

Several reptiles, including Snakes and Turtles, also trace their roots back to the dinosaur epoch. Other connections to this ancient period include Frogs and Lizards. Certain Jellyfish species even predate the dinosaurs, their lineage extending back to the earliest seas. Birds, Mammals, Insects, and Fish evolved alongside the dinosaurs, diversifying into the vibrant array of species we observe today.

The Coelacanth, once believed extinct with the last dinosaurs, and Horseshoe Crabs, possessing an intriguing evolutionary path, share this vast history. Finally, Sturgeons, some of the oldest fish species in existence, also share the natural history stage with dinosaurs. The ongoing existence of these animals offers us a living link to our planet’s past, and a glimpse into the dynamically interwoven narrative of life on Earth.

I’ll delve into the thrilling lives and survival tactics of these ancient species. We’ll explore their origin stories, their journey through millions of years, and the unique qualities that helped them persist.

I’ll also highlight some fascinating facts, like the ostrich being the closest living relative of the T. Rex. So if you’re ready to embark on a journey back in time, stick around!

I assure you that this exploration into the world of prehistoric life and its current descendants will be a captivating adventure. Let’s get started!

15 Species That Coexisted with Dinosaurs

The Mesozoic era staged an epoch of remarkable biodiversity, highlighted by the mighty Tyrannosaurus and the colossal Archelon turtle, both distinguished reptiles of the time. Evidence of their existence, uncovered from fossils, paints a vivid picture of this era’s eclectic ecosystems.

Among other remarkable beings, herbivorous dinosaurs such as the Apatosaurus and Brontosaurus thrived, contributing to the era’s dynamic life. As Sauropod family members, these massive creatures took centre stage in the ecosystems of the period. Fossils serve as a testament to their existence and offer a window into their lifestyles.

However, the flamboyant pageant of life in the Mesozoic era met a devastating close with the Cretaceous–Paleogene extinction event. This cataclysmic event slew the vast majority of plant and animal life, including the Tyrannosaurus, Archelon, Brontosaurus, and Apatosaurus.

Despite this mass extinction, survival prevailed in the form of resilient reptiles which evolved into the varied forms we see today. These survivors stand as a testament to life’s incredible endurance, linking the present to the time of the dinosaurs and adding significance to their continued study.

Dinosaurs were not the only fascinating creatures that roamed the Earth during the Mesozoic era. Let’s journey back in time and explore 15 remarkable species that coexisted alongside these prehistoric giants.

Sea Turtles

Starting our list is sea turtles, particularly the green sea turtle. According to the North Carolina Aquarium at Port Fisher, sea turtle fossils prove that these creatures were in the waters some 164 million years ago. 

Since dinosaurs lived for 180 million years, they were bound to intersect with sea turtles at some point. The sea turtle species that green sea turtles evolved from was the Archelon, which lived in the Late Cretaceous Period. 

The Archelon was absolutely massive, about 15 feet long and 4,900 pounds. It’s believed the Archelon lived in the Western Interior Seaway, which was muddy and shallow. There, predatory fish species might have tried to eat it, including prehistoric sharks. 

However, dinosaurs are largely believed to have coexisted with the creature that became today’s sea turtle. (Source)

Horseshoe Crabs

Horseshoe crabs go way, way back, like almost 500 million years back to the Lower Ordovician Period, which was part of the Paleozoic Era. Chelicerata was probably the horseshoe crab’s earliest ancestor. The two look quite alike!

What’s interesting is not only that horseshoe crabs predated dinosaurs, but that they’ve gone unchanged for millions of years. It seems that while dinosaurs roamed the earth, horseshoe crabs were unthreatened. These living fossils kept surviving and are still here today. (Source)

Tuatara

The tuatara, a unique creature that has lived alongside dinosaurs, is a testament to the resilience and adaptability of prehistoric animals. These reptiles existed alongside dinosaurs, managing to survive the mass extinctions that wiped out their colossal counterparts.

The tuatara, as an ancient relative of dinosaurs, showcases traits that have enabled its survival over the eons, traits that can still be observed in animals today. Its nocturnal habits, specialized eyes for hunting in the dark, and diverse diet are all evolutionary advantages that have allowed it to persist in a world vastly different from the one it originally inhabited.

If you’ve never heard of the tuatara, here’s what you should know. It’s a reptile species from New Zealand that might look like a lizard but is anything but. As a member of the Rhynchocephalia order, their existence dates to 250 million years ago during the Triassic Period.

So what did it do back then? Probably a lot of what the tuatara does now. This creature is somewhat nocturnal, coming alive at night. The size of their eyes is designed for hunting prey even in dim or dark conditions. Their diet includes snails, spiders, beetles, frogs, and lizards. They even eat other baby tuataras. 

Although they can be speedy, they’re mostly slow-moving animals. According to a 1994 report from the Journal of the Royal Society of New Zealand, they were living even when the first humans came around. 

Unfortunately, that might not be the case for much longer. Climate change is killing off these creatures since temperature dictates the tuatara gender. The higher the temps, the more males that are born. Without females, the tuatara line won’t be able to continue.  

Lobsters

Lobsters might go back 480 million years, suggests this CBS News piece, where they evolved from a gigantic species called the anomalocaridid, which was part of the Radiodonta order of arthropods. 

The anomalocaridid fossil, which was uncovered around 2015, was seven feet long and contained dual pairs of legs. Its filter-feeding system suggested the creature ate plankton, even though at its size, it could easily have ingested smaller animals. 

Cockroaches

When it comes to bugs, cockroaches have been here forever and will likely stay here forever. Their existence dates back around 350 million years ago, which was the Carboniferous Period. At the time, cockroaches didn’t have internal ovipositors, an organ that helps in laying eggs.

This 2020 article in science news resource Cosmos talks about recovered amber samples of cockroaches that date to the Cretaceous Period, which was a popular dinosaur time. 

So, did dinos eat cockroaches? We don’t see why not. 

Any large dinosaur could easily pierce through the shell of a cockroach. Then again, such large species would not be sated by a small creature like the cockroach, so the bug might have gotten by relatively unscathed. 

Duck-Billed Platypus

In 2009, paleontologists in Shandong Province, China unearthed a fossilized skull of a creature believed to be platypus-like, says this Smithsonian Magazine article. 

The creature’s wingspan was highly overestimated, likely due to translational mistakes in the Chinese text when converted into English. According to the findings, the platypus would have had an amazing wingspan of 52 feet. Could this really be animals that lived with dinosaurs that are still alive today – or rather their related species? That just doesn’t seem likely.

Other findings mention how around 2008, a jaw fossil was recovered that appears to be from a platypus relative. The date of the fossil is believed to be 120 million years ago, which would have been during the Cretaceous Period.  (Source)

Sea Star

The sea star, more commonly known as the starfish, includes nearly 2,000 species. One of those, known as the Pentasteria, lived during dinosaur times. 

You would almost think this starfish was like today’s starfishes, as it has a mouth as well as five unique arms. 

The main difference between the Pentasteria and today’s starfish is that the former lacked suction discs that would have allowed it to feed on shelled creatures. 

While it would be nice to know more about prehistoric starfish, finding a whole specimen is like tracking down the elusive needle in a haystack. What paleontologists do have are ossicles, which are calcite pieces from the starfish’s skeleton. 

Like many creatures we’ve talked about so far, starfish was believed to have lived about 450 million years back during the Ordovician Period.

Sharks

Sharks have been around for over 400 million years and were one of the first vertebrates to evolve. They are still around today, although their numbers have declined due to overfishing.

When did sharks first appear? Early fossil evidence for sharks was found in the Late Ordovician Period, 400 million years ago.

Here’s a small introduction to our table. Our table will provide information about the sharks during the Carboniferous Period, also known as the ‘golden age of sharks’, and the Cenozoic era. We have categorized the information into three sections: the time period, characteristics of the period, and characteristics of the sharks during that time.

Time Period	Characteristics of the Period	Characteristics of Sharks
Carboniferous Period (357.2 to 299.9 million years ago)	Global temperatures were higher than they are today, and carbon dioxide levels in the atmosphere were much higher.	Sharks were smaller during this period, not yet having evolved into the giant forms seen later.
Cenozoic Era	This era saw a significant evolution and diversification of life on Earth.	Sharks grew into giants. They were about 16 meters long and had teeth about 6 inches across, which means they could have preyed on dinosaurs.

Megalodon was a fossil shark that lived in the Pliocene.
The Megalodon is a prime example of an ancient shark that lived during the Cenozoic Era. This era began 65 Mya and lasted until the end of the last ice age. The Megalodon was a giant shark that grew to over 100 feet long and weighed 60 tons.

A Megatooth shark is a large, extinct species of shark that lived during the Cenozoic Era. These ancient sharks evolved into modern-day sharks.

Bees

The next time you swat away a bee, just think that dinosaurs would have had to contend with the same insect. Bees were found via fossilized records that date back 100 million years. They and dinosaurs would have shared the earth for more than 30 million years.

There’s an argument over whether bees died when dinosaurs went extinct or if they made it through the extinction event. Experts will staunchly defend both sides of this argument. What seems to be true is that some bee species did carry on to today’s times while others died with the dinosaurs.

Snakes

Aquatic or burrowing lizards are the ancestors of snakes, which were thought to live in the Jurassic Period. As the Paleocene Epoch occurred, which was after dinosaurs went extinct, snakes began diversifying into more of the species around today.

While we don’t know if dinosaurs ate snakes, we’re certain that snakes ate dinosaurs. In 2010, National Geographic reported on a fossilized snake skeleton in India that preserved a serpent-like snake going to town on dinosaur eggs.

Crocodiles

The first time that crocodilians appeared on the earth was 95 million years ago, during the Late Cretaceous Period. Many dinosaurs were crocodilians, such as Deinosuchus, Suchosaurus, Neosuchia, Notosuchia, and Protosuchia. 

We know that these crocodilians are no more, but the creatures that gave way to modern-day alligators and crocodiles still exist. The question becomes, how? 

Apparently, it was due to their body shape, believes some experts. Their body design would have allowed crocodilians to withstand many environmental changes that occurred after the asteroid impacted the earth.

Further, crocodiles can live in pitch blackness or light, in water or out of it. The crocodilians that couldn’t all perished. 

Salamanders

In 2020, Russian scientists found amphibian remains that date back to about 168 million years ago, says UK news site Evening Standard. 

The recovered salamander species, called Egoria malashichevi, was part of what are stem salamanders. A stem salamander is an ancient species that so far seems to originate exclusively in Russia. 

These ancient salamanders alive in the time of dinosaurs would have lived in large bodies of water, whereas today, salamanders prefer smaller bodies of water.   

Frogs

The Triadobatrachus is considered the first proto-frog. Its home was what is today Madagascar, but 250 million years back during the Early Triassic Period. 

However, there’s some evidence that proto-frogs could have been even older than that, like 265 million years ago during the Permian Period.

Today, we have more than 7,300 different frog species, which is a ton! If you’ve ever wondered why so many types of frogs exist, it might be due to the extinction event that killed off the dinosaurs. 

According to a 2017 BBC article, frogs began diversifying roughly 66 million years ago, the same time as the Cretaceous-Paleogene extinction event. The BBC quotes research published in the journal PNAS that states that up to three unique frog lineages occurred right after extinction. These lineages accommodate about 88 percent of the frogs that live today.

Dinosaurs and frogs shared the earth simultaneously, at least for a little while. Which one was the predator and which was the prey? Frogs would have preyed on smaller dinosaurs, especially huge, extinct proto-frogs like the Beelzebufo ampinga. 

Fun fact: the nickname for this frog is the “frog from hell”. It’s believed to have been large enough to consume theropods. 

Chickens

The next time you have chicken for dinner, you’re eating the same meal that dinosaurs might have consumed. Well, sort of.

Around 2000, Maarten van Dinther, an amateur fossil collector, found the skull of what some call a wonderchicken. The species, named Asteriornis, lived some 66.7 million years ago, says National Geographic. While not exactly a chicken (related to chickens and ducks), it walked with the dinosaurs.

The chicken/dinosaur connection goes deeper than that, though. Smithsonian Magazine and many other sources report that the T. Rex’s closest relative on this earth today isn’t the crocodile or alligator. It’s the ostrich and the chicken.

It makes sense when you consider that T. Rex was more than likely feathered, although exactly to what extent, we’re still not sure. Plus, if you take the time to study a live chicken, you’ll begin to notice similarities in the anatomy and stance of a chicken and a T. Rex.

It sounds crazy; chickens aren’t even reptiles! Yet scientists’ collagen sample from a T. Rex collected in 2003 proved a match to ostriches and chickens. 

For the record, alligators are the second-closest living relative of T. Rexes. 

Ostriches 

Knowing that, we bet you’ll look at ostriches differently now the next time you’re at the zoo or see one on safari. We do want to point out that we’re talking about ostriches here, not emus. The two birds might look alike, but there are key differences.

Ostriches are larger (even though emus are the second biggest), and they’re faster, with a speed difference of about 10 miles per hour between an ostrich and an emu in a foot race. For the record, emus could be related to dinosaurs as well! (Source)

How Did They Survive Extinction? A Few Theories

Most of the animals we listed today are not regarded as the smartest in the animal kingdom. That distinction is regarded for crows, pigs, octopi, and elephants. So how did animals of moderate to high intelligence survive an event that killed hundreds of species of dinosaurs?

Well, since people weren’t there, we can’t really say for sure, but we can provide some hypotheses. Without further ado then, here’s what the above 15 animal species had that dinosaurs might have lacked, which was indeed the difference between life and death.

If you are interested in knowing what animals are closely related to dinosaurs, I wrote a full article on just about this subject. Check it out here: The 9 Closest Living Things to Dinosaurs (Not Only Birds)

Diet Diversity

When a mass extinction event occurs like the one that killed off the dinosaurs, it’s not only the victims that are affected. The surviving species are as well. The food chain is now all out of whack, making former predators become prey and vice-versa.

Here is a comparison of the survival strategies of animals during the Cretaceous-Paleogene extinction event. The table below illustrates the dietary habits and requirements of crocodiles and herbivorous dinosaurs, and how these factors affected their survival during this critical period.

Animal	Dietary Habits and Survival Strategy
Crocodiles	Crocodiles were able to survive the Cretaceous-Paleogene extinction event due to their varied diet. They could consume almost anything that came their way. This adaptability allowed them to survive even when food was scarce.
Herbivorous Dinosaurs	Herbivorous dinosaurs, such as the Triceratops, had a much more limited diet, consuming only certain types of shrubs or trees. This dietary restriction made their survival dependent on the availability of their specific food sources. Once these were depleted, the dinosaurs faced extinction.
General Observation	The amount of food an animal required for survival also played a crucial role during this period. Food was likely sparse in the weeks, months, or even years following the extinction event. Animals that could survive on less food had a better chance of survival.

That again brings us to crocodiles, as they might be able to go up to a year without food. If that was the case with early crocodilians, then it makes sense that they wouldn’t die off easily. It’s also reasonable that crocodiles kept that evolutionary trait to this day. 

Good Hiding Spots 

Another way that animals might have gotten through the Cretaceous-Paleogene extinction event was they knuckled down and found a good spot to hide. For instance, cockroaches were believed to hide in caves, which could be why they made it.

We’ve talked about them a lot, but crocodiles can live in water or outside of it as well as in light or dark conditions, which is a point we mentioned earlier. 

The animals that could find spots to hide or adapt quickly to a new environment were those that made it through and are still here today. 

Luck

Although the Cretaceous-Paleogene extinction event was far-spreading, some parts of the planet might not have been as strongly affected. In the areas that were, maybe forced climate change caused conditions to improve enough to encourage survival in animal species that otherwise would not have lived.

Or it could have just been dumb, blind luck. Even paleontologists and scientists aren’t completely sure how some of today’s animals made it through the extinction event, just that they did. 

Conclusion 

Many animals that we share the planet with today were alive in some form in the age of the dinosaurs. From chickens to lobsters, sea turtles to frogs, and bees to starfish, it’s a humbling, fascinating tale to see how these animals evolved over the millions of years and survived the KT extinction event. 

Frequently Asked Questions – What Animals Lived With Dinosaurs