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are tortoises related to dinosaurs?

Are Tortoises Descendants of Dinosaurs?

(Last Updated On: September 21, 2023)

Tortoises date back to the Permian ages, more than 250 million years ago, long before dinosaurs.

Chelonians are much smaller and outlived dinosaurs, but that hasn’t stopped some scientific community members from suggesting that tortoises are descendants of dinosaurs.

Tortoises didn’t evolve from dinosaurs, as they were huge, fast-moving, and had high metabolic rates.

Dinosaurs were warm-blooded, explaining their rapid growth rates, which are similar to mammals. Unlike most dinosaurs, tortoises have slow metabolisms, are cold-blooded, and have no teeth.

Birds and crocodiles share more genetic and physical characteristics with dinosaurs, while tortoises have more in common with snakes and lizards.

We’ll explore the history of tortoises and dinosaurs to understand where their genetics meet and diverge.

Are Tortoises Older Than Dinosaurs?

Tortoise remains have been traced as far back as 250 million years ago.

This means that the species has been around since the Permian period, and dinosaurs first appeared during the Triassic period (between 243 and 233 million years ago).

Tortoises evolved to their current form 200 million years ago. Some believe the larger, faster, and sharp-toothed animals that lived among dinosaurs in the Triassic era, like the archelon turtle, weren’t tortoises.

Did Tortoises Live with Dinosaurs?

Turtles pre-date dinosaurs because they came into being 250 million years earlier.

Dinosaurs and tortoises lived together for millions of years, sometimes even in the same environments.

This was possible because most dinosaurs were plant-eaters and didn’t prey on tortoises. Lush greenery covered the Earth during the Triassic and Jurassic periods, which provided food for both species.

Tortoises and turtles co-existed with the 100 or so dinosaur species that were carnivorous. By the time dinosaurs had evolved, they were in the Jurassic era.

Tortoises had long since developed hard shells that provided more than adequate protection.

There exists a genetic relationship between dinosaurs and tortoises. However, the link is so distant that most scientists don’t consider it worthy of further study.

What is known is that both species belong to the archosaur family, which includes animals with a single hole between their eyes and nostrils.

According to the California Academy of Sciences, new genetic sequencing technologies indicate that turtles (the species that tortoises belong to) are in the Archosauria family.

This includes birds, crocodiles, and dinosaurs. Of course, these results aren’t widely accepted by scientific experts. We can’t be certain that a link exists, but it’s under review.

Furthermore, how two species that co-existed for millions of years evolved to have completely different features remains a mystery.

Some hypothesize that their direct ancestors had the same parent ancestors. Meanwhile, others claim that dinosaurs were more advanced versions of tortoises and turtles.

are tortoises like dinosaurs?

Are Tortoises Like Dinosaurs?

There are so many differences between the two species that it’s hard to believe they once co-existed.

Dinosaurs were massive, even compared to giant tortoises, and were most likely warm-blooded. Meanwhile, tortoises are the opposite in both regards.

Modern tortoises differ significantly from the ancestors that co-existed with dinosaurs.

For instance, earlier tortoises had teeth, like dinosaurs, and some didn’t even have shells. The fossil of one such turtle was found in China in 2018; its phylogenetic profile was published in Nature.

The Eorhynchochelys Sinensis was about 2 meters long (like some dinosaurs) and had a tail and long teeth. These physical characteristics seem to have gone away through evolution.

Concerning size, which is arguably the main visible difference between the two animals, available evidence suggests that tortoises weren’t always as small as them.

The archelon was a turtle larger than most land animals, measuring about 4.5 meters long with a 5-meter wingspan for its flippers.

Even this ancient ancestor lacked the characteristics that made dinosaurs iconic. These include long back legs, high metabolic rates, and long, replaceable teeth.

How Did Tortoises Survive The Mass Extinction Event?

It’s widely believed that about 65 million years ago, a large meteorite struck the Earth. This triggered a series of volcanic eruptions that released billions of greenhouse gases into the atmosphere.

The planet became dark, cold, and uninhabitable for up to 90% of living organisms, including dinosaurs. Ironically, tortoises were among the few surviving animals, which marked the end of their long coexistence with dinosaurs.

After years of study, scientists identified several factors that most likely gave tortoises and turtles an edge over their more imposing and fearsome relatives. These include the following:

Relatively Safe Habitats

At the time of the meteor strike, most tortoises lived in aquatic habitats and fed on crustaceans and aquatic plants. This kept them relatively safe from the fallout effects that mostly affected land-based life.

Slow Metabolism

Tortoises burn energy at low rates and can survive for long periods with little food and oxygen.

This is unlike most land animals. In the aftermath of the apocalypse, when food, light, and oxygen were in short supply, low metabolic rates were key to survival.

Ability to Brumate

Cold temperatures drive tortoises to brumation, where they can remain for months without food. Experts suggest that the surviving turtle species did this after the apocalyptic event to ensure their survival.

You could argue that if dinosaurs were close relatives of tortoises, they wouldn’t have been completely wiped out, and vice versa.

Are Giant Tortoises Dinosaurs?

Only birds and crocodilians, to some extent, meet the minimum qualifications to be classified as dinosaurs. Even then, it still wouldn’t be fully correct.

Giant tortoises, like all tortoises, lack one of the key distinguishing features of dinosaur-like animals: structural holes on the sides of their skulls.

So, in essence, tortoises (including giant tortoises) have more in common with the long-extinct turtles of the Triassic and Permian periods than dinosaurs.

Are Ancient Giant Tortoises Dinosaurs?

Nonetheless, there are some similarities between the two animals, particularly in the physical sphere. In 2015, Yale University discovered a 260-million-year-old fossil of an animal called eunotosaurus.

The juvenile reptile, which was about 1 foot long, has since come to be regarded as the ancestor of modern tortoises (and, in particular, giant tortoises).

Among the key features that the fossil exhibited were:

  • No shell. Instead, a hard, slightly rounded, and elongated ribcage provided protection.
  • Large size.
  • Omnivorous.

Most importantly, researchers noticed small openings in the fossil’s skull, similar to dinosaurs and other diapsid reptiles like crocodiles and birds.

Due to this discovery, a new school of thought suggests that anapsids (the group that tortoises belong to) were originally part of the diapsid reptiles. That is before they underwent divergent evolution at some point in the Permian age.

Of course, more research and discussion are needed in this area before concluding. Even then, proof of common ancestry would still be insufficient to class giant tortoises as dinosaurs, as the 2 species have far too many structural and genetic differences.

Like the T. Rex, some dinosaur species were carnivorous, while no tortoise or turtle was ever carnivorous. Dinosaurs always had fast metabolic rates and shorter lifespans.

Giant tortoises have low metabolic rates, enabling them to live for as long as 150 years.

how long have tortoises been around?

How Long Have Tortoises Been Around?

Tortoises have been around for about 230 million years in their current form. Technically, the species goes further than 260 million years if you acknowledge that most tortoises are genetic relatives of the eunotosaurus. This makes these slow-moving reptiles the oldest vertebrates on Earth. 

If you trace the genetic tree, you’ll find that turtles are direct descendants of the long-extinct anapsids. They lived 300 million years ago, long before the Permian period.

The anapsids are basal (or foundational) reptiles identified by the lack of skull openings or fenestra. Over the years, the anapsids had divergent evolution, with some becoming synapsids (typically all mammals).

Meanwhile, most changed into diapsids (turtles, crocodilians, lizards, birds, and snakes).

What Did Prehistoric Tortoises Look Like?

Tortoises are a species that have undergone the least evolutionary changes since the Triassic period.

Thus, prehistoric tortoises didn’t look much different from modern ones. Nonetheless, there are noticeable differences between Permian turtles and today’s tortoises.

For instance, the eunotosaurus is the oldest discovered turtle fossil. It had a long tail and no shell. The earliest shelled turtle was the proganochelys, which lived 230 million years ago.

The odontochelys semitestacea, discovered in China in 2008, was classed as a turtle, although it only had a half-shell. It lived 220 million years ago and had a long tail, a mouth full of teeth, and broad ribs.

The key attributes of prehistoric turtles were teeth, tails of varying lengths, large statures (e.g., the archelon and prostostega), and bent backs.

While most had shells, not all had the hard shells we see today. The archelon, for instance, had a relatively soft shell, as did the odontochelys.

For a long time, it was unclear how and why turtles evolved from having no shells to having very hard shells within the space of a few million years.

This was solved following the discovery of the pappochelys, regarded as the intermediate species between the two groups.

Although it doesn’t look like any modern tortoises, Pappochelys had a wide body and expanded ribs, topped with strong dermal bones that appear to be precursors of shells.

Tortoises aren’t considered dinosaurs in the scientific community. However, this opinion may change as more fossils are found, and scientific research is performed.

Dinosaurs and tortoises lived during the same timeframe and shared some genetic links. The question is, will there ever be enough links to consider them relatives?