Tortoise

Tortoises are reptiles in the family Testudinidae within the order Testudines, which means "tortoise" in Latin. Like all testudines, tortoises have a special shell that helps protect them from predation and other dangers. Their shell is very hard, and they can pull their necks and heads inside it for safety, a trait they share with other members of the suborder Cryptodira.

Tortoises come in many different sizes. Some, like the Galápagos giant tortoise, can grow longer than 1.2 metres (about 3.9 feet), while tiny ones such as the speckled Cape tortoise have shells just 6.8 centimetres (about 2.7 inches) long. A few types of tortoises, including the Galápagos giant tortoise and the Aldabra giant tortoise, can weigh more than 100 kilograms (about 220 pounds).

Most tortoises are active during the day, which means they are diurnal, but some may also be more active at dawn or dusk, depending on the temperature, making them crepuscular. They tend to be reclusive, meaning they like to keep to themselves. Tortoises are known for living very long lives—longer than any other land animal. While many live over 150 years, one famous Aldabra giant tortoise named Adwaita might have lived as long as 255 years! On average, tortoises can live between 80 and 150 years. Despite their slow movement, tortoises are fascinating creatures that can survive for many decades in the wild.

Terminology

Different places use words like "turtle," "tortoise," and "terrapin" in different ways. In American English, "turtle" is a general word for all animals in the order Testudines, while "tortoise" means slow land-dwelling types. For example, the box turtles live on land but are called turtles, not tortoises.

In British English, "tortoise" is often used for any land-dwelling animal in the order Testudines. The word "terrapin" in Britain usually means small turtles that live in fresh or brackish water, like the diamondback terrapin. Australian English traditionally uses "tortoise" for freshwater turtles, even though true land tortoises are not from Australia. Some experts there like the term "freshwater turtle" to avoid confusion.

Biology

Most tortoises lay small groups of eggs, usually just one or two. The eggs take a long time to hatch, often between 100 and 160 days. After the eggs are laid, the mother tortoise covers them with sand and leaves them. When the baby tortoise is ready, it uses a special tooth to break out of the egg and starts its life alone. Baby tortoises have a small sac inside that gives them food for a few days until they can find their own food.

Tortoises can live for a very long time, sometimes over 150 years. They are known for their long lives and are symbols of long life in some cultures. The number of rings on a tortoise's shell can sometimes help guess its age, but this is not always right because it depends on how much food and water they have.

Distribution

Tortoises live in many parts of the world, from southern North America to southern South America, around the Mediterranean basin, across Eurasia to Southeast Asia, in sub-Saharan Africa, Madagascar, and some Pacific islands. They are not found in Australasia. These tortoises can live in deserts, grasslands, scrublands, and forests, from sea level up into the mountains. Most of them like dry areas.

Some islands once had very large tortoises. Tortoises can go a long time without food or water, which helps them travel across oceans. Today, there are only two types of giant tortoises left: the Aldabra giant tortoise on Aldabra Atoll and the Galapagos giant tortoise on the Galapagos Islands. Sadly, many giant tortoises on other islands were lost because of human activity.

Diet

Tortoises are mainly herbivores, which means they eat plants. They enjoy eating grasses, weeds, leafy greens, flowers, and sometimes fruits. Each tortoise species has its own special dietary needs.

Main article: Herbivores
Further information: Worms, Insects

Behavior

Tortoises communicate in ways that are different from many other reptiles. Because of their shell and short legs, they don’t use many visual signals. Instead, they use their sense of smell to tell if another tortoise is male or female. This helps them find a mate.

They also use touch during fights and courtship. In these moments, tortoises will bump into each other to show strength or interest.

Taxonomy

This species list follows Turtle Taxonomy Working Group (2021) and the Turtle Extinctions Working Group (2015).

Family Testudinidae Batsch 1788 includes many types of tortoises. Some well-known kinds are the Aldabrachelys gigantea (Aldabra giant tortoise), Astrochelys radiata (radiated tortoise), Centrochelys sulcata (African spurred tortoise), and Chelonoidis niger (Galapagos giant tortoise). There are also many extinct tortoises known only from fossils, such as Aldabrachelys abrupta and Chelonoidis cubensis.

Phylogeny

Tortoises have been studied to learn about their history. Scientists use molecules and DNA to make family trees. These trees show how different tortoise species are related. This research helps us understand how tortoises have changed over millions of years. New studies keep updating what we know about their family ties.

In human culture

Further information: Cultural depictions of turtles

See also: World Turtle

Tortoises have been important in many cultures. In Hinduism, Kurma was one of the forms of the god Vishnu. In Chinese and Japanese traditions, people believed tortoises had special powers. Their shells were used to make predictions.

Tortoises were also part of big events. In 1968, two Russian tortoises flew around the Moon on a spacecraft named Zond 5 and came back safely.