The Idiots Guide to Everything: Turtles

Posted on October 25, 2012


A very cool animal.

When I was young, turtles were incredibly cool animals. Like most boys of my generation, The Teenage Mutant Ninja Turtles were the height of awesome, and there is even a photo of myself and my sister, Cerys, dressed in full Ninja Turtle get up. Imagine my amazement as a love of Dinosaurs grew to find out that turtles existed back in these times. Indeed, turtles are one of the oldest known reptile groups, more ancient in fact than lizards, snakes and crocodiles, with the earliest known turtle dating around 215 million years ago in the Triassic period. These are fantastically fascinating animals.

Turtles are reptiles, of the order Testudines, who are characterised by their iconic shell. Turtles, tortoises and terrapins all fall under this order, and the differences between all three have been a source of confusion for many years. A turtle is any reptile that lives in a shell, with a tortoise being a turtle that lives on land but often enters the water to drink, cool off or evade potential predators. Some languages don’t have this issue however, as there if one word to denote all 3 versions. In Spanish, this word is ‘Tortuga’; the Russians refer to them as ‘Cherepakha’ and the Japanese ‘Kame’.

The largest living turtle is the Leatherback Sea Turtle, with a potential shell length of 200cms. The Leatherback can reach a weight of up to 900kg. Larger turtles existed in prehistoric times however, with the very largest being a sea turtle that was thought to have been up to 15feet long. The smallest turtle is the Speckled Padloper Tortoise, which lives in South Africa, growing to a meagre 3.1 inches in length. Turtles breathe air, whether they live in water or on land. Their shell means that they do not breathe as most reptiles do, instead having to push air into the mouth before pushing that further into its lungs. Turtles are also famous for laying their eggs on land in huge numbers, before abandoning them. Once the eggs hatch, the little baby turtles slowly make their way towards the water, where they are left to fend for themselves. There is no known species of turtle where the mother cares for the young.

Of course, the most iconic part of a turtle is the shell. The upper shell is scientifically referred to as a carapace, with the underbelly shell known as the plastron. These two are joined together by a series of bony bridges found on the animal’s side. There are around 60 bones found in the shell. The shell is attached to the ribs and backbone of the turtle, which means it is eternally unable to escape its shell. Turtles are in fact divided into 2 groups, depending on how they withdraw their necks into aforementioned shell. These are ‘Cryptodira’, which draw the neck in whilst contracting it under the spine, and ‘Pleurodira’, who contract their necks to the side. The colour of the shell is usually a brown, black or olive green, but there are many species with more flashy colours, such as red and yellow. The shell provides another difference between turtles and tortoises, which of course is based on whether they call the land or the sea home. For land dwellers, the shell is heavy and lumber some, where as the aquatic livers have light, soft shells. The heavy shell of the tortoise leads to its reputation as being a slow animal.

One thing I was not aware about turtles is their fantastic night vision ability. This is due to the high number of rod cells in their retina, rod cells being cells that function in less intense light. The fascinating manner of the eyes continues with glands that are found nearby, which produce tears high in salt in order to get rid of excess salt picked up in the water. Turtles have no teeth, and use their jaws to cut and chew food, which is then swallowed using the tongue. Turtles are completely unable to stick their tongue out, which is a shame as it would be completely adorable. However, the earliest known turtles had teeth, and couldn’t retract their heads at all.

Turtles and tortoises have always been prominent animals in culture and mythology, including the Ninja Turtles mentioned at the beginning of this. They are frequently depicted as being easy going (Michelangelo) and wise (Donatello), and are frequently used as an emblem of longevity, stability and wisdom, the most famous myth being that of a turtle carrying the world on its back. It’s not all good however, as in Mandarin it is considered bad form to wear a green hat. The green hat represents the turtle, and the turtle is regarded as being insufficiently virile.

The turtle is an animal that transcends generations and has lived through more history than most. It survived whatever killed off the dinosaurs and the weekly attacks of Shredder and Krang. They have carried the world on their backs for centuries, and wandered slowly across our television screens in the famous credits for ‘One Foot in the Grave’. The turtle is a truly remarkable creature.