Turtles are reptiles that have hard shells to protect them against predators. These reptiles are the oldest and most primitive group of reptiles. They evolved millions of years ago. They can be found in nearly every climate. 

Although "Turtle", "tortoise," and "terrapin" are frequently used interchangeably as synonyms however, there are clear differences between the types chelonians. 

– Turtles spend the majority of their lives in water. Their bodies are designed for aquatic life and have flippers or webbed feet. Except for the occasional lay of eggs in the sand, sea turtles don't venture far from the ocean. Freshwater turtles are found in lakes and ponds. They climb up onto rocks or logs to enjoy the warmth of the sun.

– Tortoises can be considered a land animal. They are able to walk on the ground because of their stumpy feet. Their strong forelimbs allow them to dig burrows and slide underground when it gets too hot.

– Terrapins can live on land or in water. They are usually found in swamps, ponds and lakes, but they also inhabit rivers and streams.

A turtle's shell consists of a modified version of its ribcage, as well as a part of its vertebral column. Keratin is used to make scutes, which are the same material as human fingernails. 

The adaptive nature of turtles means that they can be found on all continents, except Antarctica. The majority of turtle species can be found in South Asia and southeastern North America. Only five species are found in Europe 

Turtles are not social creatures Most turtles are active during the day, spending their time foraging for food .

Turtles are not silent. Some sound like electric motors while others sound like humans belching, and some bark like dogs. The South American red-footed tortoise clucks like an chicken. 

Many turtles are omnivores. They eat many different foods, depending on the species. Mollusks, small fish, insects, and plants are all eaten by musk turtles. The cooter turtle is mostly vegetarian while the green sea turtle eats only grasses, algae, and small fish. 

All turtles produce eggs. They locate a spot on the ground to lay their eggs and then dig a nest in dirt or sand. Then they walk away. They are not able to care for their young. 

Turtle fossils dating back to the Triassic Period are some of the oldest known. They date back around 220 million years ago. 

Largest turtles can weigh over a thousand pounds. The leatherback turtle, the largest of all sea turtle species, can weigh between 600-2,000 pounds and reach 8 feet in length.

 A turtle's outer shell is not an excoskeleton. It's a modified rib cage which forms part of the vertebral column.

Turtles loose their first "baby teeth" within one hour. Hatchlings have an "egg tooth", which is a tooth on the beak that helps them hatch from their shell. The egg tooth is usually gone within an hour of hatching.