Tortoise

Tortoises are any of the slow-moving, terrestrial, reptile species belonging to the family Testudinidae. Although a tortoise has a protective outer shell similar to that of a turtle, it can be differentiated from turtle species by being land-dwelling. Turtles, on the other hand, are Testudines that are either aquatic or semi-aquatic. Tortoises are the oldest living terrestrial animals in the world, with some species having a life expectancy of more than 150 years.

Tortoise Scientific Classification

Animalia
Chordata
Reptilia
Testudines
Testudinidae

Scientific Classification

Tortoise

Animalia
Chordata
Reptilia
Testudines
Testudinidae

Types of Tortoise

List of Different Types of Tortoise

Approximately 49 different species of tortoises are categorized under 18 extant genera. Some of the most commonly found tortoise species are listed below:

  • Aldabran giant tortoise
  • Radiated tortoise
  • Angonoka tortoise
  • Sulcata tortoise or African spurred tortoise
  • Red-footed tortoise
  • Southern wood tortoise or Argentine tortoise
  • Yellow-footed tortoise or Brazilian giant tortoise
  • Galapagos tortoise
  • Cape Berkeley giant tortoise or Wolf Volcano giant tortoise
  • James Island giant tortoise or San Salvador giant tortoise
  • Duncan Island giant tortoise or Pinzon giant tortoise
  • South African bowsprit tortoise or Angulated tortoise
  • Karoo padloper, Boulenger’s Cape tortoise, or Karoo dwarf tortoise
  • Speckled padloper tortoise
  • Berger’s Cape tortoise or Nama padloper
  • Indian star tortoise
  • Burmese star tortoise
  • Mojave desert tortoise
  • Bolson tortoise
  • Berlandier’s tortoise or Texas tortoise
  • Gopher tortoise
  • Morafka’s desert tortoise or Sonoran desert tortoise
  • Common padloper, beaked Cape tortoise, or parrot-beaked tortoise
  • Greater dwarf tortoise or greater padloper
  • Yellow-headed tortoise or elongated tortoise
  • East Indian tortoise or Forsten’s tortoise
  • Travancore tortoise
  • Bell’s hinge-back tortoise
  • Serrated hinge-back tortoise or forest hinge-back tortoise
  • Home’s hinge-back tortoise
  • Lobatse hinge-back tortoise
  • Speke’s hinge-back tortoise
  • Natal hinge-back tortoise
  • Pancake tortoise
  • Brown tortoise or Asian giant tortoise
  • Impressed tortoise
  • Geometric tortoise
  • Kalahari tent tortoise or serrated tent tortoise
  • African tent tortoise
  • Madagascan spider tortoise
  • Flat-backed spider tortoise or Madagascan flat-tailed spider tortoise
  • Leopard tortoise
  • Russian tortoise
  • Spur-thighed tortoise or Greek tortoise
  • Egyptian tortoise
  • Hermann’s tortoise
  • Marginated tortoise

Physical Description and Appearance

Size: Their length varies depending on the tortoise species, with the smallest species being the speckled padloper, having a shell length of 2.4-3.1 inches while the largest is the Aldabra giant tortoise and Galapagos tortoise, both with an average shell length of 36-48 inches.

Tortoise

Weight: The smallest species of tortoise, the speckled padloper, weighs about 95-160 g while the largest, Aldabra giant tortoise weighs about 150-250 kg.

Body: It has a small- to large-sized body characterized by cylindrical hind feet and hind limbs, with each digit in its feet having two or lesser number of phalanges. Its front legs are flat and have large scales while the back legs resemble that of an elephant.

Shell: Its carapace or shell is high-domed, but some species have spherical shells with a flat base.

Sexual Dimorphism: The differences between females and males vary from one species to another. Male tortoises, in some species, have a longer neck plate than the females and the plastron (the underside) is bent inwards. In general, the females have smaller, dropped down tails while the males have longer tails that are pulled up to the side.

Distribution

Tortoises are distributed across Southern North America, Southern South America, the Mediterranean basin, in sub-Saharan Africa, Madagascar, Eurasia, Southeast Asia, and various Pacific islands.

What kind of Habitats do Tortoises live in

Tortoise species are typically found inhabiting various types of natural environments, including arid grasslands, deserts, wet evergreen forests, scrublands, and places at sea level or mountainous regions.

Tortoise Habitat
Tortoise Shell

How long do They live

Tortoises are possibly the longest-living land dwellers in the world, but the longest-living species is a topic of debate. While most tortoise species usually survive for 80-150 years, Galapagos tortoises are known to live for more than 150 years. Adwaita, an Aldabra giant tortoise, is believed to have died at an age of 255 years.

What do They Eat

Most tortoise species are herbivores and they typically feed on weeds, grasses, flowers, leafy greens, and a few fruits. Some species may eat insects, worms, and carrion. Pet tortoises are usually given fresh vegetables, including dandelions, collard greens, and kale; some fruits such as grapes, melon, and apples, and a small amount of alfalfa and timothy hay.

Behavior

  • Tortoises are generally shy and reclusive by nature. They are fearful and may get stressed due to over handling by humans.
  • They remain active during the day, but may show crepuscular behavior depending on ambient conditions. It means that they can also be active during twilight.
  • Male tortoises perform head butting or banging as mating rituals as well as to show dominance. A fight often follows if both the tortoises are male wherein each of them tries to flip the other over. The Mediterranean and spur thighed tortoises are likely to head bang or head butt more often.
  • Males of some species, such as the spur thighed, may ram the female tortoises, whereas the marginated, horsefields, and Hermanns may bite them for stimulating ovulation.
  • During the winter months, tortoises sleep or slow down all their activities to survive the cold weather. This behavioral trait is called hibernation and tortoises usually hibernate for 2-4 months.
  • Galapagos tortoises migrate to the highlands of the island where they spend the cool, dry season because the vegetation grows there despite no rainfall. They return to the lower, warmer regions where there is plenty of nutritious vegetation during the rainy season.

Adaptations

  • Tortoises have a hard carapace or shell that protects them from predators or other threats. They retract their heads and necks back into their shell when attacked or threatened.
  • They use their strong legs and tough claws to dig large burrows, which help in escaping from not just predators but also hot and cold weather conditions.
  • Some species such as the desert tortoise have the ability to store water in the bladder and endure high amounts of urea in the blood, which prevents loss of moisture. They can live without food and water for a long time.
  • There are some tortoises, including the Galapagos tortoises, which show incredible survival adaptations. On islands with shrubs and short grasses, the tortoises have shorter necks and legs, while on parts of the island with taller plants and grasses, the tortoises have longer necks and legs.
Tortoise Eggs
Baby Tortoise

Reproduction and Mating

Wild tortoises typically attain sexual maturity at 15-20 years of age. Female tortoises are ready to mate when the length of their shell reaches about 7-8 inches. Courtship and mating can occur any time that they are not hibernating. It involves the male bobbing its head and nipping at the front edges of the shell and the front legs of a female. It causes the female to stop and retract its head and limbs, after which the male moves to the rear and mounts.

The female usually lays a clutch of 4-8 eggs from early May-middle of July. It may lay two clutches several weeks apart and incubate the eggs for about 90-160 days. Before laying the eggs, the female tortoise digs a shoe-shaped nest about 4 inches deep. After laying a clutch of eggs, the female covers them with soil using its hind legs. It soon leaves her eggs and moves away from the nest without showing any interest in the hatchlings.

Conservation

There are some critically endangered tortoise species including the Angonoka or Ploughshare tortoise, Indian star tortoise, and Burmese star tortoise that are threatened by poaching for the pet trade. Several organizations and conservation groups, including the Global Wildlife Conservation, Turtle Conservancy, and IUCN, work together to protect the habitat of endangered tortoises, as well as monitor illegal trade to combat poaching.

Tortoise-FAQs

1. Can tortoises swim?

Tortoises are land-dwelling reptiles and cannot swim. They will simply drown when kept in deep water.

2. Why do tortoises live so long?

Tortoises, specifically the giant tortoises, have slow metabolism implying that they burn energy at a much slower rate as compared to the faster animals. Slow metabolism means less energy is burnt, which is why less damage is caused to their cells.

3. How old is the oldest tortoise?

Jonathan, a Seychelles giant tortoise, is the oldest living tortoise in the world with an estimated age of 188 years.

4. Can tortoises hear?

Tortoises have an eardrum (hidden under the scales) located on the side of their head or neck. However, tortoises do not have the ability to hear much. They can hear and respond to only a few sound frequencies made by dueling adults, hatching eggs, or the mating process.

5. Do tortoises carry salmonella?

Yes, reptiles including tortoises and turtles carry salmonella bacteria that can be transmitted to people.

6. Do tortoises have teeth?

No, turtles and tortoises completely lack teeth. They do, however, have strong beaks.

Tortoise Picture
Tortoise Image

Interesting Facts

  • Tortoises in the African arid lands, Galapagos Islands, and Neotropical rain forests play an important role in dispersing seeds for many trees, plants, and fungi.
  • The oldest tortoise recorded was Tui Malila, a radiated tortoise from Madagascar that was gifted to the Tongan royal family by Captain James Cook.
  • A tortoise’s brain is extremely small. Tortoise species from the Central and South Americas lack the hippocampus, a part of the brain associated with learning, memory, spatial navigation, and emotion.