What is a turtle?
A: Turtles are an order of reptiles known as Testudines, characterized by a shell developed mainly from their ribs.
Modern turtles are divided into what two major groups?
A: The side-necked turtles and hidden neck turtles, which differ in the way the head retracts.
How many living and recently extinct species of
turtles, including land-dwelling tortoises and freshwater terrapins are
Where are turtles found?
A: On most continents, some islands and, in the case of sea turtles, much of the ocean.
Like other reptiles, birds, and mammals, they breathe
air and do not do what?
A: Lay eggs underwater, although many species live in or around water.
Genetic evidence typically places them in close
relation to what?
A: Crocodilians and birds.
Turtle shells are made mostly of what?
A: Bone; the upper part is the domed carapace, while the underside is the flatter plastron or belly-plate.
Its outer surface is covered in scales made of what?
A: Keratin, the material of hair, horns, and claws.
The carapace bones develop from ribs that grow sideways
and develop into what?
A: Broad flat plates that join up to cover the body.
Turtles are ectotherms or "cold-blooded", meaning what?
A: That their internal temperature varies with their direct environment.
They are generally opportunistic omnivores and mainly
feed on what?
A: Plants and animals with limited movements.
Sea turtles are the only reptiles that migrate long
distances to do what?
A: To lay their eggs on a favored beach.
Turtles have appeared in what around the world?
A: Myths and folktales
Some terrestrial and freshwater species are widely kept
Turtles have been hunted for what?
A: Their meat, for use in traditional medicine, and for their shells.
How are sea turtles often killed accidentally?
A: As bycatch in fishing nets.
Turtle habitats around the world are being what?
As a result of these pressures, many species are
threatened with what?
What is the largest living species of turtle?
A: The leatherback turtle, which can reach over 2.7 m (8 ft 10 in) in length and weigh over 500 kg (1,100 lb).
What is the smallest living turtle?
A: The Chersobius signatus of South Africa, measuring no more than 10 cm (3.9 in) in length and weighing 172 g (6.1 oz).
The shell of a turtle is unique among vertebrates and
serves to do what?
A: To protect the animal and provide shelter from the elements.
Land-dwelling turtles are more dome-shaped, which
appears to make them what?
A: More resistant to being crushed by large animals.
Aquatic turtles have flatter, smoother shells that
allow them to do what?
A: Cut through the water.
Some turtle species have pointy or spiked shells that
A: Extra protection from predators and camouflage against the leafy ground.
The lumps of a tortoise shell can tilt its body when it
gets flipped over, allowing it to do what?
A: Flip back.
In male tortoises, the tip of the plastron is thickened
and used for what?
A: Butting and ramming during combat.
All turtle species have how many neck vertebrae?
Due to their heavy shells, turtles are what on land?
How fast can a desert tortoise move?
A: At only 0.22–0.48 km/h (0.14–0.30 mph).
By contrast, sea turtles can swim how fast?
A: 30 km/h (19 mph).
The limbs of turtles are adapted for various means of
locomotion, and most have how many toes?
Tortoises are specialized for terrestrial environments
and have what?
A: Column-like legs with elephant-like feet and short toes.
The gopher tortoise has flattened front limbs for doing
A: Digging in the substrate.
Freshwater turtles have more flexible legs and longer
toes with what?
A: Webbing, giving them thrust in the water.
Some of these species, such as snapping turtles and mud
turtles, mainly walk where?
A: Along the water bottom, as they would on land.
Others, such as terrapins, swim by paddling with all
four limbs, switching between the opposing front and hind limbs, does what?
A: It keeps their direction stable.