Sea turtles are amazing creatures that have been around for over 100 million years. These reptiles spend most of their lives swimming the world’s oceans, but they always return to sandy shores to lay their eggs.
Sea turtle hatchlings are tiny when they first emerge from their sandy nests, but these little turtles grow fast once they enter the water. After just a few years, some species have nearly quintupled their hatchling size!
In this article, we’ll take a quick look at the different stages of sea turtle development and growth. We’ll learn how big hatchlings are when they hatch, how quickly they reach maturity, and how large adult sea turtles can ultimately grow.
Their growth rates vary by species, but in general sea turtles put on an incredible amount of size in not much time. By learning more about the sea turtle life cycle, we can better understand and appreciate these ancient mariners of the ocean world.
So let’s dive in and explore the answer to the question – just how fast do sea turtles actually grow?
How Fast Do Sea Turtles Grow?
Sea turtles grow extremely fast in their early years, putting on tremendous size and weight in their first decade of life.
As hatchlings first emerging from sandy nests, sea turtles are just around 1-2 inches long and weigh less than an ounce. But many species of sea turtles will reach 2 feet or more in shell length and over 100 pounds in only 5-10 years.
For example, loggerhead sea turtle hatchlings start off tiny at just 30 grams on average. But they can grow to over 300 pounds in weight as large juveniles. Green sea turtles have a similarly rapid growth spurt, going from less than an inch to over 3 feet as 10-15 year olds.
Leatherbacks put on even more dramatic size, with hatchlings smaller than a ping pong ball rapidly becoming 500-1000 pound adults in 6-10 years.
While growth rates do vary by species, it’s clear than in their first decade of life, sea turtles undergo a remarkably fast and substantial expansion in size.
Adding tons of additional weight and multiple feet of length in less than 10 years allows young sea turtles to better avoid predators and have enough strength and stamina to embark on long open ocean migrations.
So while sea turtles live a long time as adults, their growth journey all starts with a remarkably fast sprint in early life.
Growth Rate of Different Sea Turtles
There are seven species of sea turtles found around the world. Each species grows at a slightly different rate. Below we will explore the known growth rates of the major species of sea turtles.
Green Sea Turtle Growth Rate
The green sea turtle (Chelonia mydas) is found mainly in tropical and subtropical waters. Green sea turtles grow rather slowly in their early years.
During the first 5 years, a green turtle may grow only around 0.5 inches (1.3 cm) per year in length. The growth rate increases substantially once the turtle switches from an omnivorous to herbivorous diet at around 2 to 5 years old.
After switching to eat mainly seagrasses and algae, young green sea turtles can grow up to 1.2 inches (3 cm) per year.
As adults, female green sea turtles tend to grow a bit larger than males. Adult female green sea turtles reach an average length of 3.3 feet (1 meter) and weight around 350 pounds (159 kg).
Adult male green sea turtles grow to an average of 2.9 feet (0.9 meters) in length and weigh around 290 pounds (132 kg) on average. It takes approximately 20-50 years for green sea turtles to reach full adult size and weight.
Loggerhead Sea Turtle Growth Rate
Loggerhead sea turtles (Caretta caretta) are found in subtropical and temperate regions around the world. Loggerheads experience a very high growth rate in their early years, but it slows as they mature.
Studies have shown that loggerhead sea turtles grow at an exponential rate for about the first four years of life. During their first year alone, loggerhead sea turtles typically grow around 1.2 inches (3 cm) in a month.
For the next 2 to 3 years, juvenile loggerheads continue putting on weight and length rapidly if food is abundant. By age 7, loggerhead sea turtles typically achieve an average straight carapace (top shell) length between 20–28 inches (51–71 cm).
Growth rates slow down when loggerheads reach sexual maturity at around 20 to 30 years old. Adult female loggerheads reach around 3 feet (0.9 meters) long and weigh approximately 250 pounds (113 kg) on average.
Flatback Sea Turtle Growth Rate
Found only in the waters around Australia, flatback sea turtles (Natator depressus) remain one of the least studied sea turtle species globally.
However, researchers do know that flatback sea turtles appear to grow at moderately fast rates throughout their long lives. Studies have shown that very young flatback sea turtles often measure only around 0.8 inches (2 cm) in length right after hatching.
But within their first year, they can quadruple their size. Juvenile flatback sea turtles are estimated to grow around 0.4–0.8 inches (1–2 cm) per year until they reach maturity.
As adults, flatback sea turtles typically reach around 3 feet (0.9 meters) long and weigh approximately 150 pounds (70 kg). They reach full adult size after an estimated 10 to 50 years, depending on food availability and habitat.
Hawksbill Sea Turtle Growth Rate
Found in tropical oceans around the world, hawksbill sea turtles (Eretmochelys imbricata) are slow growing compared to other sea turtle species.
They spend more time as juveniles than other sea turtles. Researchers estimate that hawksbill sea turtles spend around 20–40 years in developmental habitats after hatching before reaching full adulthood. During their early juvenile stage, hawksbills grow on average around 0.6 inches (1.6 cm) in carapace length each year.
Growth slows as they reach maturity, which for hawksbill sea turtles occurs at a small size compared to other sea turtles. Adult hawksbill sea turtles reach an average length of just 2.2 feet (0.7 meters) and weigh 100-150 pounds (45-70 kg).
Leatherback Sea Turtles Growth Rate
Leatherback sea turtles (Dermochelys coriacea) are the largest turtles on Earth. They also have unusually rapid growth rates compared to other sea turtles. Baby leatherbacks typically measure around 2.0–3.6 inches (5–9 cm) in length.
But astonishingly, within only their first 4 to 6 years, leatherback turtles can grow up to 4.5 feet (1.4 meters) in total length. This represents an exponential growth rate of over 0.7 inches (2 cm) per month.
Leatherback sea turtles reach astounding sizes not seen in other species. Mature leatherback turtles average around 5.2 feet (1.6 meters) in carapace length and weigh from 500 to 2000 pounds (225-900 kg). Their rapid growth rate slows substantially once leatherbacks reach adult size.
It is estimated leatherbacks reach maturity between ages 12–25 years. Still, leatherback sea turtles never stop growing during their 40 to 50+ year lifespan as long as prey is sufficiently abundant.
Kemp’s Ridley Sea Turtle Growth Rate
Kemp’s ridley sea turtles (Lepidochelys kempii) are the smallest species of sea turtle. They grow at a slow to moderate rate. Female Kemp’s ridleys reach sexual maturity earlier and grow a bit larger on average than males.
Adult female Kemp’s ridleys grow to an average length of around 2 feet (.6 meters) and weigh approximately 100 pounds (45 kg).
Adult male Kemp’s ridleys measure on average around 1.8 feet (.5 meters) long and weigh around 80 pounds (35 kg). It takes Kemp’s ridleys around 10 to 20 years to reach full maturity and adult size.
Olive Ridley Sea Turtle Growth Rate
Olive ridley sea turtles (Lepidochelys olivacea), closely related to Kemp’s ridleys, have one of the most variable and habitat dependent growth rates among sea turtles. Those olive ridleys living in particularly cold water environments stay much smaller in size.
However, olive ridleys in tropical regions grow substantially larger. Adult female olive ridleys reach 2 to 2.5 feet (.6 to .8 meters) in length on average and weigh 100 to 115 pounds (45 to 52 kg).
Male olive ridleys grow a bit smaller at around 1.5 to 2 feet (.5 to .7 meters) and 50 to 80 pounds (23 to 36 kg). It takes olive ridleys approximately 10 to 15 years to reach these full adult sizes.
Growth Chart Of Sea Turtles
The below table summarizes the average adult sizes reached for both male and female individuals of the major species of sea turtles:
| Species | Adult Females | Adult Males |
|---|---|---|
| Green Sea Turtle | 3.3 ft, 350 lbs | 2.9 ft, 290 lbs |
| Loggerhead Sea Turtle | 3 ft, 250 lbs | 2.5 ft, 225 lbs |
| Flatback Sea Turtle | 3 ft, 150 lbs | 2.5 ft, 100 lbs |
| Hawksbill Sea Turtle | 2.2 ft, 100-150 lbs | 2 ft, 90-140 lbs |
| Leatherback Sea Turtle | 5.2 ft, 500-2000 lbs | 5 ft, 450-1500 lbs |
| Kemp’s Ridley Sea Turtle | 2 ft, 100 lbs | 1.8 ft, 80 lbs |
| Olive Ridley Sea Turtle | 2-2.5 ft, 100-115 lbs | 1.5-2 ft, 50-80 lbs |
As shown, leatherback sea turtles reach much larger sizes than other species of sea turtles. Kemp’s ridley and hawksbill sea turtles remain the smallest species. But all sea turtles demonstrate unique growth patterns and longevity.
Sea Turtle Growth Factors
Many factors play a key role in determining sea turtle growth rates and their ability to reach maximum adult sizes including:
1. Habitat Status:
Sea turtles that reside in high quality marine habitats with plenty of nourishing prey and few predators will grow faster.
Things like abundance of jellyfish, crabs, seagrasses, sponges, and other food sources allow for rapid growth.
Meanwhile, sea turtles in habitats impacted by fishing, loss of foraging grounds, marine debris, and coastal development tend to grow slower and remain smaller in size.
2. Captive or Wild:
Sea turtles raised in captivity under perfect conditions often grow quicker and larger than wild turtles exposed to threats like predators, fishing gear entanglement, and boats.
For example, a study found captive-raised Kemp’s ridley sea turtles gained weight 50% faster compared to wild juveniles. This demonstrates the challenges sea turtles face surviving in the wild.
3. Body Size or Age:
As referenced earlier, sea turtles exhibit exponential growth for the first several years of life followed by slowed growth upon reaching maturity after 10 to 50 years depending on species.
By adulthood, sea turtles devote less energy to growth and more energy into reproduction and migration. Their growth rate slows but does not stop completely.
4. Genetics:
Evidence suggests that genetics account for 10-30% of factors influencing sea turtle growth capacity. Some individual sea turtles likely inherit genes from their parents that give them the ability to grow quicker or attain larger sizes. Researchers continue working to better understand these genetic influences.
Conclusion
In summary, sea turtles are slow maturing reptiles that can take over a decade to reach adult size and 30+ years to reach maximum size.
Leatherback sea turtles stand out as the fastest growers capable of gaining 200 pounds in only 4 to 6 years after hatching. Green and hawksbill sea turtles rank among the slowest growing species.
Habitat conditions, age, genetics, and captive versus wild status all help determine individual growth rate. But once they reach maturity, sea turtles continue expanding in length and weight for the rest of their remarkably long lives.
Here are Some frequently asked questions about:
How fast do baby sea turtles grow in their first year?
Most species of sea turtle hatchlings grow very rapidly in their first year, anywhere from 0.4 inches to 1.2 inches (1 cm to 3 cm) per month. Leatherback sea turtles grow the fastest, capable of growing over 2 inches (5 cm) per month.
How long does it take a sea turtle to reach full adult size?
It depends greatly on the species, but it takes sea turtles between 10-50 years to attain full adult size and weight. Leatherbacks reach maturity and their immense size faster than other species, in 12-15 years. Kemp’s ridleys and hawksbills take up to 40 years to finish growing.
Do male and female sea turtles grow at different rates?
Yes, female sea turtles almost always grow larger than males of the same species. The growth rate is often similar in early years but females continue growing for longer periods of time before reaching maturity and full adult dimensions.
Do sea turtles ever stop growing?
Sea turtle growth slows down dramatically once adulthood is reached, but they continue expanding in length and weight very gradually as long as prey resources are available. Turtles in threatened habitats often stop growing due to lack of nutrients.
What is the largest sea turtle species?
The leatherback sea turtle is by far the largest, capable of reaching over 6 feet (2 meters) long and exceeding 2,000 pounds (900 kg). All other species max out at under 350 pounds (159 kg). Leatherbacks also grow at the fastest rate.
1 thought on “How Fast Do Sea Turtles Grow? Growth Rate”