Difference between Turtles and Tortoises

Key difference: The commonly understood or accepted definitions of tortoises and turtles are that tortoises are the one that live on land, whereas turtles are the one that live in water. Scientifically tortoises are the Testudinidae family, only one of the 14 extant turtle families.

Both, tortoises and turtles are reptiles from the family of Testudines. As they are closely related, they have many similarities amongst themselves. They also have a number of differences. The terms, tortoises and turtles, are not straightforward and are often construed differently. However, the commonly understood or accepted definitions of tortoises and turtles are that tortoises are the ones that live on land, whereas turtles are the ones that live in water. Scientifically tortoises are the Testudinidae family, only one of the 14 extant turtle families. The earliest known turtles date from 220 million years ago, making them one of the oldest reptile groups; older than lizards, snakes or crocodiles.

Another term is a terrapin; these are the ones that spend their time on both land and in water. They always live near water, along rivers, ponds, and lakes, and are commonly found in brackish, swampy areas. However, they are most often than not called turtles and sometimes as tortoises.

Both, tortoises and turtles are ecothermic (cold-blooded) and rely on their surrounding as a source of heat. Their body is also covered with a shell. The upper part of the shell is called Carapace, whereas the lower part of is called Plastron. The Carapace and the Plastron are attached at the end by a bridge. This means that the head and limbs of the turtle or tortoise may be withdrawn from the shell. However, the whole body can never be totally detached from it, as the shell is part of the turtle’s backbone and ribcage.

Turtles and tortoises do not have ears; however they can feel vibrations and changes in water pressure. They use this technique to find food or to detect a predator. They have a good sense of smell, which also help them seek food. The skin of a turtle or tortoise may look leathery and tough but is actually very sensitive. This is especially true of land tortoises.

Turtles and tortoises both reproduce by laying eggs, which they bury in soil, sand, or vegetation. Some species lay only a few oblong-shaped eggs, while others lay dozens to 100 or more round eggs. Once the eggs are laid, the mother abandons them. She does not incubate or care for her eggs or for the hatchlings when they emerge. Hatchlings have to fend for themselves. In many species, the temperature in the nest determines the sex of the hatchlings. If the temperature is warmer, the hatchlings will be female; in cooler areas, the hatchlings will result in males.

Essentially, turtles are smaller in size and their life spans are lower than tortoises'. Across many cultures, tortoises and turtles are symbols of longevity, wisdom and are often part of the creation myths. Currently, turtles and tortoises are in extreme danger of extinction. This is extremely true for many specific species. This is mainly due to wipeout and pollution of their natural habitats, as well as due to over hunting of the creatures.

A detailed comparison between turtles and tortoises:

	Turtles	Tortoises
Scientific classification	Animalia – Chordata – Reptilia – Testudines (Chelonii) – Cryptodira and Pleurodira	Animalia – Chordata – Reptilia – Testudines (Chelonii) – Cryptodira – Testudinoidea - Testudinidae
Habitat	Live in water	Live on land
Shells	Mostly flat, streamlined shells. Lighter in weight.	Mostly large dome shaped shells. Heavier shells.
Skin	The outer layer of the shell is part of the skin. Each scute (or plate) on the shell corresponds to a single modified scale. Turtles continuously molt their skins in small pieces.	Tortoises also shed skin, but dead skin is allowed to accumulate into thick knobs and plates that provide protection to parts of the body outside the shell.
Limbs	Amphibious turtles have webbed feet with long claws. Sea turtles have flippers instead of feet.	Bent legs with short and sturdy feet.
Eyes	Turtles have visible irises. Desert Tortoises have white irises.	Tortoises have black irises that blend in with the pupil.
Diet	Are mainly carnivores feeding on fish, worms and insects. Some are omnivores.	Most land-based tortoises are herbivores, feeding on grasses, weeds, leafy greens, flowers, and some fruits, although some are omnivorous, also feeding on insects, worms and snails.
Habits	Turtles are likely to move around in search of food, swimming even entire oceans. They rarely leave the ocean, except when the females come ashore to lay their eggs. They may climb out onto banks, logs, or rocks to bask in the sun. In cold weather, they may burrow into the mud to hibernate. Some sea turtles migrate thousands of miles through the sea on regular routes, returning every two or three years to the same beaches to lay their eggs.	Tortoises tend to stay at one place. They only venture into water to drink or to clean themselves. They tend to drown in deep waters or in strong currents. Tortoises that live in hot, dry habitats use their strong legs to dig burrows. If the sun is too hot, they slip underground.
Eggs/Birth	A turtle typically mates and lays eggs underwater or on dry, sandy beaches. There are no known species in which the mother cares for the young.	Female tortoises dig nesting burrows in which they lay from one to 30 eggs. A fully formed hatchling uses an egg tooth to break out of its shell. It digs to the surface of the nest and begins a life of survival on its own.
Lifespan	20-40 years (the oldest was 86 years).	80-150 years (The longest living tortoise is 326 years).