Tortoises and turtles belong to the same family called Chelonian or Testudines. The main thing that differs in both the reptiles is their habitat. Turtles dwell in water, whereas tortoises dwell on land. The main characteristic of both is the protective shell that is present as a defense mechanism for them. The limbs and head are protruding from the shell.
Turtles are reptiles that dwell in America and Africa. The shell of a turtle is more streamlined and lighter compared to a tortoise. To help in swimming, turtles have long claws and webbed feet. Turtles come under the category of omnivorous animals, which means they eat both vegetation as well as meat. The average number of years of the life of the turtle is 20-40 whereas tortoises can live upto 86 years.
Turtles have a unique shell made of cartilage and bones. The shell acts as a protection or shield for the turtles.
They belong to the order Testudines. The Testudines include extinct and living species.
Middle Jurassic is one of the early known members from order Testudines. It means turtles belong to a group of reptiles, which are older compared to crocodiles or snakes.
Turtles are known as ectotherms or cold-blooded animals. The meaning of cold-blooded animals is that the internal temperature of the animal changes concerning the surrounding environment.
Because of the metabolic rates of sea turtles being high, the body temperature is more than the ambient water. Turtles come under amniotes, including other reptiles, mammals, and birds.
Turtles breathe air, and they do not lay eggs in water, just like other amniotes. The temperature is a significant factor in deciding whether the egg develops to a female or male.
The name turtle does not precisely say the taxonomical and biological distinctions of the species. The word indicates water-dwelling animals in the United Kingdom.
The leatherback sea turtle is the largest existing chelonian whose length can reach 200cm and weigh around 900kg. Turtles that live in freshwater are usually smaller in size, but few of the Asian softshell turtles can also reach 200 cm length.
Turtles have two categories, based on how the retraction of their body parts back into the shell. In Pleurodira suborder the retraction of lateral is to the side, and anterior to the shoulder girdles. Whereas in Cryptodira retraction is straight back, between the shoulder girdles.
The retraction movements depend on the morphology and the arrangement of the cervical vertebrae. In the recent species of turtles, there are nine joints and eight vertebrae in the cervical column, and they are independent.
The movement of the neck is flexible because there is no fusion of vertebrae, and vertebrae are round. This nature of the neck is evolved for eating or food consumption more than protection.
The hard outer shell of a turtle is known as a carapace. The inner part of the shell that covers the belly is called plastron. Bridges are the bony structures that join the carapace and plastron. The shell has sharp scales known as scutes. A protein called keratin forms the scutes in turtles and also scales in other reptiles.
The shell of a turtle is usually brown, olive, or black. In some turtles, the green-colored shell is frequent. The shell often has markings, spots, or irregular surface.
Scientific Classification of Turtles
In general, we can define any animal in terms of their kingdom, phylum, class, clade, and order.
Turtles belong to the kingdom-Animalia, Phylum-Chordata, Class-Reptilia, Clade-Testudinata, Order-Testudines.
The subgroups are Cryptodira and Pleurodira. There are 14 living families with around 356 species.
Tortoises belong to the family Testudinae and order Testudines. The main distinction of tortoises from turtles is the land habitat. Just like turtles, tortoises also have a protective shell, which protects from predators and different threats.
The pectoral and pelvic girdles of a tortoise are within the rib cage, making them unique among vertebrates.
Tortoises are usually diurnal animals, and they tend to change temperature according to the ambiance.
Galapagos tortoises live up to 150 years, but the longest living tortoise named Adwaita is living and about 255 years old.
Tortoises live in different habitats such as grasslands, desserts, wet evergreen forests, and also in mountain areas. Tortoises are usually found in southern North America, Mediterranean Euphoria, sub-Saharan Africa, and some islands.
Commonly, most of the species in tortoises lay small eggs and about 20 in number. Same as turtles, the carapace and plastron are the shell coverings in tortoises.
Just as the concentric rings on a cross-section of a tree can give an idea about the age of the tree, rings on the shell of a tortoise can sometimes be useful in the prediction of their ages. Tortoises have the longest living time compared to any other animals.
The typical way of predicting the sex of a tortoise is to analyze its tail. If the tail is small and dropped down, then the tortoise is a female; if the tail is longer and pulled up, then the tortoise is a male.
In many species of tortoise, the size of female tortoise is larger than that of the male. The plastron of male tortoises is curved to help in reproduction.
The period of incubation is usually long in many species. The average period ranges from 100 to 160 days. Tortoises lay eggs generally at night.
Scientific Classification of Tortoises
Tortoises belong to the kingdom-Animalia,Phylum-Chordata,Class-Reptilia,
The subgroup of tortoises is Testudo graeca.
Difference Between Tortoise and Turtle
The main characteristic that easily differentiates turtles and tortoises is their dwelling. Turtles have shorter life spans compared to tortoises. Both the reptiles have protection on their bodies known as the shell. The shell of a tortoise is harder as they live on land and subject to more harsh conditions. The scientific classification of turtles and tortoises is mostly the same.