Turtles: Understanding Their Maximum Size And Growth Potential

Turtles vary in size depending on their species and type, with some weighing less than a penny at birth and others growing to several hundred pounds. The leatherback sea turtle is the largest living sea turtle species, growing up to 6 feet in length and weighing between 550 and 2,000 lbs. The largest land turtle is the giant tortoise, which can be found on the Galapagos Islands in the Pacific and Seychelles in the Indian Ocean. These tortoises have shells that approach 4 feet in length, and some weigh more than 400 pounds.

The largest sea turtle species

The leatherback sea turtle (Dermochelys coriacea) is the largest of all living turtles and the heaviest non-crocodilian reptile. It is also the largest living marine turtle and the largest sea turtle species.

Leatherback turtles can reach lengths of up to 2.7 metres (8 ft 10 in) and weigh between 500 and 2,000 lbs. The largest leatherback ever recorded was 2.56 metres (8.4 ft) long and weighed 916 kg (2,019 lbs). They are easily differentiated from other sea turtles by their lack of a bony shell. Instead, their carapace (or shell) is covered by oily flesh and flexible, leather-like skin, which gives them their name.

Leatherback turtles have a global range, although there are distinct subpopulations. They are found as far north as Alaska and Norway and as far south as the southernmost tip of New Zealand and Cape Agulhas in Africa. They tend to nest in the tropics, and within the United States, they are known to nest in southeast Florida, Puerto Rico, and the U.S. Virgin Islands.

Leatherback turtles feed primarily on jellyfish and are the only living species in the genus Dermochelys and family Dermochelyidae. They are considered vulnerable, and some of their subpopulations are critically endangered.

The largest land turtle species

The largest living giant tortoise, or land turtle species, are found on the Galápagos Islands in the Pacific Ocean and the Seychelles in the Indian Ocean. These giant tortoises can weigh up to 417 kg (919 lbs) and grow to 1.3 m (4 ft 3 in) in length. The straight-line length of their high-domed shells can reach close to 4 feet. Some of these giant tortoises weigh over 400 pounds.

The Aldabra Atoll and Fregate Island in the Seychelles, as well as the Galápagos Islands, are home to two distinct species of giant tortoise. The Aldabra giant tortoise, which is native to the Indian Ocean's Aldabra Islands, can grow to a length of 4.9 feet and weigh up to 800 pounds. The Galápagos giant tortoise, on the other hand, has a length of 6.1 feet and weighs approximately 880 pounds.

The phenomenon of animal species evolving to unusually large sizes on islands, in comparison to their continental relatives, is known as island gigantism or insular gigantism. Giant tortoises are no longer considered classic examples of island gigantism, as similarly massive tortoises have been found to have once been widespread.

The giant tortoise is an iconic species from the Galápagos and is considered the largest living tortoise in the world. They are classified as vulnerable and are threatened by introduced species on the islands, such as dogs, cats, and cattle.

Factors affecting the size of a turtle

The size of a turtle is influenced by various factors, including species, age, diet, gender, habitat, UV light exposure, temperature, and living conditions.

Species

The species of a turtle is the most significant factor in determining its size. For example, the leatherback turtle, the largest living species, can reach over 2.7 m in length and weigh over 500 kg. In contrast, the smallest living turtle, the speckled Cape tortoise, has a shell length of only 3.1 inches and weighs about 5 ounces.

Age

Older turtles tend to be larger than younger ones.

Diet

A healthy and balanced diet can accelerate a turtle's growth rate.

Gender

Female turtles are generally bigger than males, usually by about 1 inch.

Habitat

The habitat of a turtle can impact its size. For instance, turtles in captivity tend to be bigger than wild turtles due to better diets and living conditions.

UV Light Exposure

UV light exposure is essential for turtles as they require sunlight to synthesise vitamin D, which is necessary for calcium absorption and bone growth.

Temperature

Temperature plays a crucial role in the growth and development of turtles. Warmer temperatures can promote faster growth, while cooler temperatures may slow it down.

Living Conditions

Living conditions, such as the amount of space available and the quality of the environment, can influence a turtle's size.

Common pet turtle species and their size

Turtles are quiet and relatively undemanding pets, but they are not very interactive or cuddly. They can also carry diseases, and their famously long lifespans mean they may even outlive you!

The size of a turtle depends on its species, but most pet turtle species reach a size of 4 to 12 inches.

Red-Eared Sliders

Red-eared sliders are one of the most common aquatic turtle species kept as pets. They tend to be friendlier and more sociable than other turtles, and they are widely available, usually costing around $20. Male red-eared sliders are some of the easiest turtles to care for. They require a large tank with adequate areas for basking, UV lighting, and a good water filtration system.

Red-eared sliders can grow to a decent size, ranging from 5 to 12 inches in length, with females typically larger than males.

Western Painted Turtles

Western painted turtles are distinctive and attractive, with shells marked in red, yellow, and olive. They are not big, but they do need a large tank or outdoor space, a good water filtration system, and basking lights to maintain a warm temperature.

Western painted turtles range in size from 4 to 10 inches.

Eastern Box Turtles

Eastern box turtles need a lot of space, but they are adaptable and can live indoors or outdoors. They are shy, but they are not usually aggressive, and with gentle interactions, their personality will start to show. They may even be tempted out to greet you if you have a tasty treat.

Eastern box turtles range in size from 4 to 8 inches in length.

Texas Map Turtles

Texas map turtles are sensitive to water quality and must have a spot to bask if kept as a pet. They can range in size from 2.75 to 8.5 inches in length.

Wood Turtles

Wood turtles' habitat should include access to both water and dry land. They can grow up to 9 inches in length.

Mississippi Map Turtles

Mississippi map turtles have a distinctive dorsal fin along their shell and are sometimes called "sawbacks." They don't need as big an enclosure as some other aquatic turtles, making them a good choice for those with limited space.

Mississippi map turtles can grow up to 10 inches in length for females and up to 5 inches for males.

Common Musk Turtles (Stinkpots)

Common musk turtles are one of the more popular aquatic turtle species, and their care requirements are a little less intensive. They are not good swimmers, so the water in their enclosure should not be too deep, and they should have plenty of areas to get out and bask under UVB lighting.

Common musk turtles are small, reaching a size of 3 to 5 inches in length.

African Sideneck Turtles

African sideneck turtles are unique aquatic turtles with long necks that can't be fully retracted into their shell. They have more complex care requirements than some other turtles, needing very clean water that is changed weekly, as well as a varied diet to prevent vitamin deficiencies.

African sideneck turtles grow to a size of 8 to 12 inches in length.

Yellow-Bellied Sliders

Yellow-bellied sliders are one of the most popular aquatic turtle species to keep as pets, as they are relatively hardy when given the right diet, enclosure, and lighting. They need a large tank or outdoor enclosure, as they are bigger than some other aquatic turtles.

Yellow-bellied sliders can grow to a size of 5 to 9 inches for males and 8 to 13 inches for females.

Reeve's Turtles

Reeve's turtles are probably the most sociable of all the turtles on this list. With care and patience, they can even enjoy being stroked, which is unusual for an aquatic turtle. Their care requirements are similar to red-eared sliders, but they are smaller and require a less large enclosure.

Reeve's turtles typically grow to a size of 6 to 9 inches in length.

The biggest pet turtle species

Turtles are great pets, but they require a lot of care and commitment. Before getting a turtle, it is important to research their specific needs and requirements. Turtles can vary greatly in size depending on their species, and it is crucial to ensure that you have enough space to accommodate your pet as it grows. Here are some of the biggest species of turtles that are commonly kept as pets:

Red-eared Sliders

Red-eared sliders are one of the most popular aquatic turtle species kept as pets. They are generally friendly, active, and social. These turtles can grow to a decent size, typically ranging from 5 to 12 inches in length, with females being larger than males. Red-eared sliders can live up to 30 years and require a large tank with adequate basking areas, UV lighting, and a good water filtration system.

African Sideneck Turtle

The African sideneck turtle is a unique aquatic turtle species with a long neck that cannot be fully retracted into its shell. They are popular due to their distinctive appearance and size, typically growing to 8 to 12 inches in length. These turtles require a large tank, preferably at least 75 gallons, and weekly water changes to maintain water quality. They also need a varied diet and access to basking platforms with UV lights.

Eastern Box Turtle

Eastern box turtles are adaptable and can be kept indoors or outdoors with the right housing. They typically grow to a size of 5 to 7 inches in length. These turtles prefer a humid environment and require a shallow pool of water, a moist substrate, and a UVB basking light if kept indoors. Eastern box turtles can live up to 50 years in captivity and even longer in the wild.

Western Painted Turtle

Western painted turtles are attractive and distinctive, with detailed shell markings. They are aquatic and require a large tank or outdoor space, as well as basking lights and a good water filtration system. Western painted turtles can grow up to 10 inches in length and can live for over 50 years. They are shy and do not enjoy frequent handling.

Mississippi Map Turtle

The Mississippi map turtle is a smaller species, with females reaching up to 8 inches and males up to 5 inches in length. They are excellent swimmers and are frequently found near permanent bodies of water such as rivers and streams. These turtles are intelligent and personable, often swimming up to their owners looking for treats. They require a standard aquarium or turtle pond and benefit from basking areas.

Common Musk Turtle (Stinkpot)

The common musk turtle is a popular aquatic species, known for its small size and less intensive care requirements. They typically grow to a size of 3 to 5 inches in length. These turtles are not strong swimmers, so their water should not be too deep, and they should have plenty of areas to get out and bask under UVB lighting. Despite their name, they only release a musky odour when scared or threatened.

Frequently asked questions