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How Big Are Sea Turtles?

Sea turtles in general are much bigger than freshwater turtles. Some such as the leatherback can reach lengths of almost 6 ft. this turtle can reach a mass of 1982 lb. Other sea turtles are also massive.

Even the smallest sea turtle which is the kemp’s ridley grows up to a length of 28 inches and a weight of 110 lb (which is about 50 kg). The size of these animals means that they have few predators as adults.

Also, the older the sea turtle, the larger it will be. So how big are sea turtles? Well, sea turtles can weigh anywhere from 66 lb to almost 2000 lb.

Table of Contents

1. Sea Turtles
1.1. Hawksbill Sea Turtle
1.2. Leatherback Sea Turtle
1.3. Loggerhead Sea Turtle
1.4. Green Sea Turtle
1.5. Kemp’s Ridley Sea Turtle
1.6. Flatback Sea Turtle
1.7. Olive Ridley Sea Turtle
2. FAQ
3. Conclusion

Sea Turtles and Their Sizes

Hawksbill Sea Turtle

Hawksbill Sea Turtle (Eretmochelys imbricata) swimming along the rocky coral bottom of the ocean near Queensland, Australia
Hawksbill Sea Turtle (Eretmochelys imbricata) swimming along the rocky coral bottom of the ocean near Queensland, Australia. – Source
  • Biological Name: Eretmochelys imbricata
  • Common Names: Hawksbill
  • Carapace Length: 24.6 to 44.9 inches (or 62.5 to 114 cm)
  • Average Length: 34.3 inches or 87 cm
  • Weight/Mass: 78.6 to 279.7 lb (or 35.7 to 127 kg)
  • Average Weight/Mass: 176.2 lb or 80 kg

Hawksbill turtles have heart-shaped carapaces although juveniles’ carapaces are more heart-shaped while matured individuals have more elongated carapaces. The hawksbill turtle gets its common name from the shape of its head which resembles the beak of a bird or hawk.

Compared to other sea turtles, the hawksbill turtle is quite small although it is larger than the Ridley sea turtles on average. The average length of the hawksbill turtle is 34.3 inches or 87 cm. The length of this turtle can be anywhere from 24.6 to 44.9 inches (or 62.5 to 114 cm).

The average weight or mass of mature individuals of the species is 176.2 lb or 80 kg. The weight of a mature individual can be anywhere from 78.6 to 279.7 lb (or 35.7 to 127 kg).

Mature males have longer thicker tails, longer claws, a more concave plastron, and brighter coloration than females do. The average length of a hatchling as recorded in the Caribbean is 42 millimeters.

This is the straight carapace length. The average weight/mass of hatchlings from this region is 13.5 to 19.5 grams.

Leatherback Sea Turtle

Leatherback Sea Turtle (Dermochelys coriacea) swimming onto the shores of Sable Island, Nova Scotia, Canada
Leatherback Sea Turtle (Dermochelys coriacea) swimming onto the shores of Sable Island, Nova Scotia, Canada. – Source
  • Biological Name: Dermochelys coriacea
  • Common Names: Leatherback, luth, leathery turtle, lute turtle
  • Curved Carapace Length: 39.6 to 68.4 inches (or 100 to 175 cm)
  • Total Length: 72 to 86.4 inches (or 183 to 220 cm)
  • Max Span of Carapace: 106.3 inches (or 270 cm)
  • Average Straight Carapace Length: 57 to 63 inches (or 145 to 160 cm)
  • Max Carapace Length: 83.9 inches (or 213 cm)
  • Weight/Mass: 550 to 1,540 lb (or 250 to 700 kg)
  • Max Weight/Mass: 1982.38 lb

The leatherback is the largest turtle and the largest sea turtle. This species is also considered the largest reptile and by others the largest non-crocodilian reptile.

This species is known as the leatherback because it lacks a hard shell. Instead of a hard shell, this turtle has a leathery back.

The leatherback can reach a span of the carapace of 106.3 inches (or 270 cm). The span is measured from the tip of the left front limb to the tip of the right front limb.

This turtle can reach a maximum carapace length of 83.9 inches (213 cm). The species has a curved carapace length of 39.6 to 68.4 inches (or 100 to 175 cm).

The total length of the species is 72 to 86.4 inches (or 183 to 220 cm). The average carapace length of the species is 57 to 63 inches (or 145 to 160 cm).

The weight/mass range of the species is 550 to 1,540 lb (or 250 to 700 kg). The species have been known to reach a weight of  1982.4 lb or 900 kg.

There may be differences in size from one region to another. The adults that nest in  French Guiana have an average adult size of 748 lb or 339.3 kg and an average curved carapace length of 61.2 inches or 1.54 m.

A large adult was found in Sansspit in Pakistan. This individual had a curved carapace length of 84 inches or 213 cm and a weight of  1,433 lb or 650 kg.

The adults from the Caribbeans have an average adult size of 384 kg (or 847 lb) and an average curved carapace length of 1.55 m or 61.2 inches.

Loggerhead Sea Turtle

Loggerhead Sea Turtle gliding through the water
Loggerhead Sea Turtle gliding through the water.
  • Biological Name: Caretta caretta
  • Common Names: Loggerhead
  • Carapace Length: 28 to 37 inches (or 70 to 95 cm)
  • Average Carapace Length: 35 inches (or 90 cm)
  • Max Carapace Length: 84 inches (or 213 cm)
  • Weight/Mass: 169.6 to 440 lb (or 77 to 200 kg)
  • Average Weight/Mass: 298 lb (or 135 kg)
  • Max Weight/Mass: 1,202 lb (or 545 kg)

The loggerhead is known as the second-largest sea turtle and the largest sea turtle with a hard shell. These giants have barnacles and algae living and thriving on their backs.

The carapace underneath their algae and barnacle-covered backs are reddish to brownish. The plastron on the other hand is yellowish to cream.

Their skins are reddish-brown as well. The heads of this species are yellowish with males being more brightly colored.

There are two subspecies that are divided by geographic range. These are the Indian and Pacific Oceans subpopulations known as (C. caretta gigas) and the Atlantic Ocean subpopulation known as (C. caretta caretta). These subspecies have been proposed but are yet to be accepted.

The mediterranean sea loggerheads are considerably smaller than the loggerhead adults found in the Atlantic Ocean.

A mature loggerhead has a mass/weight range of 169.6 to 440 lb (or 77 to 200 kg). The average mass or weight of mature individuals is 298 lb or 135 kg. The maximum reported mass of this turtle is 1,202 lb or 545 kg.

A mature loggerhead has a carapace length range of 28 to 37 inches (or 70 to 95 cm). The average length of mature individuals is 35 inches (or 90 cm).

The presumed maximum carapace length of this turtle is 84 inches or 213 cm.

Green Sea Turtle

Green Sea Turtle (Chelonia mydas) beached onto a shore with black sand in Hawaii, USA
Green Sea Turtle (Chelonia mydas) beached onto a shore with black sand in Hawaii, USA. – Source
  • Biological Name: Chelonia mydas
  • Common Names: Green Sea Turtle, green turtle, black turtle, black sea turtle, Pacific green turtle
  • Carapace Length: 31 to 44 inches (or 78 to 112 cm)
  • Max Length: 60 inches or 153 cm
  • Weight/Mass: 150 to 419 lbs (or 68 to 190 kg)
  • Max Weight/Mass: 871 lb or 395 kg

You may think the green sea turtle is green in color but it isn’t. This turtle is named after the green coloration of the fat underneath the skin.

As such, the species is also known as the black turtle or the black sea turtle which is its coloration upon hatchling. The black coloration changes over the years. This turtle generally reaches maturity at age 27 to 50 years.

The platoon is made up of four overlapping scutes. The carapace is also made up of four overlapping scutes.

Males and females look almost the same. The differences include the size of the tail, the positioning of the reproductive organs, claws, and carapace size. Males are slightly smaller with longer tails and claws.

Green sea turtles are considered one of the largest sea turtles there. It is considered the second-largest or the third-largest sea turtle depending on your source.

Adults can reach a length of 31 to 44 inches (or 78 to 112 cm). The largest green sea turtle measured had a carapace length of 60 inches or 153 cm.

Adults can reach a mass/weight of 150–419 lbs (or 68–190 kg). The largest green sea turtle weighed and measured 871 lb or 395 kg. 

Kemp’s Ridley Sea Turtle

Kemp's Ridley Sea Turtle (Lepidochelys kempii) swimming along Texas Offshore Waters, USA
Kemp’s Ridley Sea Turtle (Lepidochelys kempii) swimming along Texas Offshore Waters, USA. – Source
  • Biological Name: Lepidochelys kempii
  • Common Names: Kemp’s Ridley sea turtle, Atlantic Ridley
  • Carapace Length: 20 to 28 inches or 51 to 71 cm
  • Average Length: 25.5 inches or 65 cm
  • Weight/Mass: 66 to 110 lbs or 28 to 50 kg

The Kemp’s Ridley is the smallest sea turtle there is. This sea turtle reaches a carapace length of 51 to 71 cm with an average length of just 65 cm.

While this may be large for a turtle overall, it is tiny for a sea turtle. As with other sea turtles, the carapace is oval in shape and streamlined for easy movement through the water.

The Kemp’s Ridley uses its front limbs to produce the power needed to move while the back limbs are used solely to steer the chelonian in the desired direction and stabilize the turtle. Similar to other sea turtles, this chelonian does not retract its limbs and head into its shell.

Regardless, the shell covers most of its body and protects the Kemp’s Ridley from injury and attacks from predators. Kemp’s Ridley reaches a mass of 28 to 50 kg.

As you can see this turtle is still quite massive despite being the smallest sea turtle there is. The carapace or the upper shell is olive-gray in coloration while the plastron (the undershell) is whitish-yellow in coloration.

In conclusion, Kemp’s Ridley has a length of 51 to 71 cm and a weight/mass of 28 to 50 kg.

Flatback Sea Turtle

Flatback Sea Turtle (Natator depressus) swimming in the Indian Ocean off the coast of Australia
Flatback Sea Turtle (Natator depressus) swimming in the Indian Ocean off the coast of Australia. – Source
  • Biological Name: Natator depressus
  • Common Names: Flatback, green turtle, Australian flatback
  • Carapace Length: 30 to 38 inches (or 76 to 96 cm)
  • Weight/Mass: 154 to 198 lb (or 70 to 90 kg)
  • Average Weight/Mass: 154.2 lb or 70 kg

The flatback is endemic to Australia – specifically in the shallow waters of the continental shelf.

This means that it has the smallest geographic range of all the sea turtle species. The species has been seen as far as Papua new guinea to forage although there is no evidence of the species nesting in Papua new guinea.

As you may have already figured out, the flatback is so-called because of its relatively flat carapace compared to other sea turtles. This gives this turtle a peculiar appearance. The flat carapace is olive green while the plastron is light yellow to whitish in coloration.

Mature individuals of the species have an average mass or weight of 154.2 lb (or 70 kg). As you can see, this turtle is relatively large.

Mature individuals have been known to be 198 lb or 90 kg. Sources show that these chelonians’ weight range is 154 to 198 lb (or 70 to 90 kg).

Mature individuals of the species have an average length of 30 to 38 inches (or 76 to 96 cm). As with most turtles, females are generally larger, however, males have longer and thicker tails and longer claws.

Olive Ridley Sea Turtle

Olive Ridley Sea Turtle (Lepidochelys olivacea) sitting on the sand at golden hour in Michoacán, Mexico
Olive Ridley Sea Turtle (Lepidochelys olivacea) sitting on the sand at golden hour in Michoacán, Mexico. – Source
  • Biological Name: Lepidochelys olivacea
  • Common Names: Pacific Ridley, Olive Ridley Sea Turtle
  • Carapace Length: 22 to 320 inches or 51 to 71 cm
  • Average Length: 25.5 inches or 65 cm
  • Weight/Mass: 66 to 110 lbs or 30 to 50 kg

The Olive Ridley is similar in size to the Kemp’s Ridley. Both turtles look very similar with the Olive Ridley being a bit bigger.

While not the largest sea turtle or even among the larger sea turtles, Olive Ridley is still quite large. It can reach a mass or weight of 110 lbs although it has an average weight of about 100 lbs or 45 cm.

In terms of length, the Olive Ridley can reach 30 inches or 75 cm. As you can see this is very similar to that of its close relative Kemp’s Ridley.

Olive Ridley weighed in Oaxaca, Mexico showed a weight range of 25 to 46 kg or 55 to 101 lb. Mature females on average weighed 78.2 lbs or 35.5 kg, and mature males on average weighed 72.8 lb or 33 kg.

As you can tell, males are generally smaller than females. However, males have larger and longer tails than females do. Additionally, the male’s carapace is longer and more tapered than the female’s.

Hatchlings weigh 0.42 and 0.82 oz or 12 to 23.3 grams.

Frequently Asked Questions

How big are green sea turtles?

Green turtles, also known as green sea turtles or black turtles, are among the largest sea turtles. This chelonian can reach a weight of 871 lb or 395 kg and a length of  60 inches or 153 cm.

Typically,  they weigh anywhere from 150 to 419 lbs (or 68 to 190 kg) and measure anywhere from 31 to 44 inches (or 78 to 112 cm).

How big are leatherback sea turtles?

The leatherback is the largest sea turtle there is. This chelonian is the largest turtle as well. In other words, it’s the largest species of the order Testudines.

This turtle can reach a carapace length of 83.9 inches (or 213 cm) and a weight of 1982.38 lb. Although, typically, a leatherback will have a weight of 550 to 1,540 lb (or 250 to 700 kg) and a length of  57 to 63 inches (or 145 to 160 cm).

How big are giant sea turtles?

The only giant sea turtles still living today are the leatherbacks, the green sea turtles, and the loggerheads.

These giants have a length of 28 inches to 63 inches and a weight of 150 lb to 1,540 lb.

How big are baby sea turtles?

Even the biggest sea turtles are of similar size to the smallest sea turtles upon hatching. So how big are sea turtles when they hatch?

Hatchlings weigh 0.42 and 0.82 oz or 12 to 23.3 grams and measure about 2 to 3 inches (5 to 8 cm) in length.

How big are the biggest sea turtles?

The biggest sea turtle is the leatherback. This turtle is pretty huge.

They can weigh 550 to 1,540 lb (or 250 to 700 kg) and measure 57 to 63 inches (or 145 to 160 cm). According to Animaldiversity.org, they can even weigh 1982.38 lb.

How big are 100-year-old sea turtles?

Very little is known about the longevity of sea turtles. Sea turtles are thought to be able to live for a hundred years.

A hundred-year-old leatherback was believed to have been found in Cornwall in 2018. This giant measured 7 foot 9 inches (2.36 m)  from the tip of the left front limb to the tip of the right front limb.

How big are 1-year-old sea turtles?

Very little is known about the size of a 1-year-old sea turtle. A 1-year-old loggerhead should be about 13 to 20 cm in curved carapace length.

Conclusion

Sea turtles are large animals. Some such as leatherbacks are as large as a small boat.

In general, these turtles are much larger than freshwater turtles. Although some softshell turtles are larger than some ridley sea turtles.

In all, sea turtles are pretty big. The biggest turtle is a sea turtle and the largest non-crocodilian reptile is also a sea turtle.

The leatherback is the largest sea turtle weighing about  550 to 1,540 lbs This is followed by the loggerhead which weighs  169.6 to 440 lbs. The smallest turtles are the ridley turtles, these weigh 66 to 110 lbs.

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