How Long Have Leatherback Sea Turtles Roamed Our Planet?
The leatherback sea turtle is the largest of all turtle species, and is also one of the largest reptiles on this planet. This amazing reptile specie can range in sizes from 4ft up to 8ft in length. They can grow to sizes which makes the average human look small. They can also weight anywhere between 250kg to 900kg as fully grown adults. Being such a big reptile, you would imagine these creatures have been able to survive for thousands of years. Which brings you to the question, how long have leatherback sea turtles roamed our planet?
You would be right in thinking that the leatherback sea turtle has been roaming our planet for thousands of years. Even then, you would still be a little bit off.
Leatherback sea turtles have actually been roaming our planet for over 150 million years. This time scale is incomprehensible to imagine, but from this time scale they are thought to have survived the extinction of dinosaurs. Scientists even believe that leatherback sea turtles thrived on our planet, right the way up until humans started exploiting sea waters for food. Ever since then, our planets leatherback sea turtles population numbers have been falling rapidly.
The Evolution of Leatherback sea turtles on our planet?
The leatherback sea turtle specie is believed to have been roaming our planet for over 150 million years. But did you know turtles haven’t always been in our planets oceans?
The oldest sea turtle species (Odontochelys Semitestacea) is believed to date back over 220 million years, which makes them one of the most primitive groups that still roam our planet. This group is known as “Reptilia” or as we call it, the reptile species.
The “Odontochelys Semitestacea” is the oldest turtles species that we know to date, due to fossil findings. This specific turtle species dates back to the Triassic Period. However scientistic believe that sea turtles actually originated and evolved from land turtles over 230 million years ago, in the Cretaceous period. No one really knows why this change was made from land to sea, but the only reasonable explanation is due to predatory threats. Therefore seeking safety in our planets oceans.
Closest Ancestor to a Leatherback sea turtle?
The earliest found and closest relative fossil found on our planet to leatherback sea turtles so far dates back roughly 120 million years. This species is called the “Desmatochelys Padillai” which was found along the shores of Columbia, with a body length that measured approximately 6.5 feet in length. However it’s believe that this early ancestor was not primitive.
Before this discovery, the “Santanachelys Gaffneyi” species was the oldest ancestry fossil referenced, but the “Desmatochelys Padillai” species is believed to be roughly 25 million years older, which now takes the thrown.
Remains of a species known as the “Archelon Ischyros” has been found to prove the closest relative to the Leatherback sea turtle which we know of today on our planet. This specific fossil species dates back to roughly 75 million years ago, and occupied the seas and oceans surrounding the Americas.
The biggest struggle the Leatherback sea turtles species had to deal with on our planet?
The human species is believed to have evolved from our ape ancestors approximately 6-8 million years ago. Sea turtles however date back way over 27 times this amount. Through out this time, turtles have survived the harshest conditions and environmental factors as the world change through the years.
The undisputed toughest struggle the sea turtle species had to face is the “Cretaceous–Paleogene”. Roughly 66 million years ago a mass extinction took place when an astroid collided with earth causing horrific destruction including, mile-high tsunami’s, enormous wildfires, and eventually, an ice age. This humongous environmental event caused destruction so bad that billions of tons of sulphur were released into our planets atmosphere, causing its temperature to rise to damaging levels.
So much sulphur was released into the atmosphere that it blocked out the sun for hundreds of thousands of years after. This caused earths temperature to rise, which changed the living eco-systems of which many species couldn’t survive. Even if they did, the millions of tons of earths crust which was exploded into the atmosphere rained down in from the sky at speeds fast enough to turn them into fireballs. After this came a global freeze, starting an Ice Age, which ended the remaining lives of dinosaur species that roamed the planet at that point in time.
As well as this, the Cretaceous–Paleogene event ended the lives of a further 75% of all other living species. Scientists believe that no Tetrapod (four limbed animal) weighing more than 25kg, other than turtles and crocodiles, survived. Amazingly, over 80% of our planets turtle species at the time of the mass extinction survived.
How did the Leatherback sea turtle species survived to continue roaming our planet?
We know that the sea turtles species is a very hardy animal. Even nowadays we know that sea turtles can withstand big changes in its habitat or natural environment to thrive. But what would it take to survive a catastrophic astroid impact?
The leatherbacks ancestors, the Archelon Ischyros species, survived due to their eating behaviours and habits. Whilst all other species of animal struggled to find food, the sea turtles slow metabolism meant they could go for long periods of time without the need for food. This behaviour has stayed with the turtle species throughout evolution, and even to this date, turtles can go months without needing a meal.
Aquatic species seemed to be somewhat protected from the destructive elements which killing off the land animals and plantations at an alarming rate. Having slow body movements and using the oceans currents to manoeuvre, turtles energy expenditure is extremely minimal, therefore are able to survive on little resources.
This acute feeding habit meant that whilst dinosaurs and land living animals were struggling to find food, turtles were relative unaffected by the events. When the seas warmed, up to 98% of the earths coral was killed and with it many species of fish which relied on it for housing, safety and food. Many aquatic animals also couldn’t adapt quick enough to the rapidly rising water temperatures. This irradiated fertility in many sea species, and only the toughest survived.
So how many sea turtles still roam our planet?
As you would imagine, it’s very hard to count the number of sea turtles which are left in the world, so these numbers always have to be estimated using different methods. Recent estimates have stated that it’s believe to be roughly 6.5 million sea turtles left in the wild to this date.
This may still sound like a lot, but these population numbers have decreased by up to 67% in the last 150 years. The main reason fo this decrease in numbers is due to human activities, which include, fisheries, pollution and coastal construction developments.
Leatherback turtles species are the worlds most endangered specie at this moment in time. The Pacific Leatherback turtle is believed to have as few as 2,300 adult females in the wild, and the Atlantic Leatherback turtle population is thought to range somewhere between 35,000 – 90,000 in total.
An average across the two leatherback species is thought to have 34,000 – 36,000 nesting females left in the wild worldwide. This number is down from 115,000 nesting females worldwide in 1980.
Where do leatherback sea turtles roam today?
Leatherback sea turtles roam between foraging grounds and nesting grounds, and are one of the most migratory animals on earth today. The leatherback turtle will travel up too, and sometimes in excess of 10,000 miles each year in search for jellyfish.
The Atlantic species roam too and from the Caribbean up the east coast of the US and Canada. Whereas the Pacific species roam too and from Southeast Asia to east coast US and Alaska.
To conclude how long have leatherback sea turtles roamed our planet, you should remember that these species were here well before human life was. Over 150 million years this turtles species has been roaming our planet. Surviving the Cretaceous–Paleogene was undoubtably it’s biggest test to overcome and thrive, which it did.
Please don’t forget that this specific species, the leatherback, is an extremely endangered turtle, which needs global help to once again thrive.