How Fast Do Snapping Turtles Grow? [Full Guide]

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If you’ve ever considered keeping a snapping turtle as a pet, you’re going to wonder, how fast do snapping turtles grow? Or, how big can a snapping turtle get? Snapping turtles are the largest turtles in North America, although their growth is quite slow.

Many factors determine how fast or slowly a snapping turtle will grow, including environmental conditions, food and nutrition, and how much sun they receive.

If you’ve ever been fascinated with how large these turtles get and wondered how they reach that enormous size, keep reading to find out more.

How Fast Do Snapping Turtles Grow?

We’ve established that snapping turtles can grow to very large sizes, but how fast does a snapping turtle grow?

Snapping turtles grow surprisingly slowly, with some only reaching full maturity halfway through their life.

However, snapping turtles will do most of their growing in the first two years of their life, and then their growth will slow down. We’ll cover that in more detail later.

The fastest that some snapping turtle populations grow is five to seven years. However, these quicker growth rates are usually only the standard for males, with females often taking over ten years to reach full maturity.

In fact, some female snapping turtles may take up to 20 years to reach their full size and maturity.

Even if a turtle has reached full maturity at a younger age, it doesn’t necessarily mean they will stop growing. If a turtle is fully mature at 5-7 years of age, their body may continue growing for several years afterwards.

Whether a turtle continues to grow after maturity likely results from environmental factors and how often they reproduce.

Snapping turtle
Common Snapping Turtle

Basking

Unlike most turtles, snapping turtles don’t like to bask on land, but will do it in water with their heads and shells poking above the surface.

Basking helps their bodies grow big and strong because it gives them exposure to important UVB rays. UVB rays produce Vitamin D3 which helps the body produce calcium. Without calcium, a turtle’s bones will not grow correctly.

Without enough calcium, turtles may develop debilitating diseases like metabolic bone disease, softshell, and shell rot.

How To Tell How Old A Snapping Turtle Is

It is possible to tell the age of a snapping turtle, although the process becomes more difficult the older the turtle is.

Growth Rings

Similar to trees, snapping turtles have growth rings on their shells that indicate how old they are. A snapping turtle’s shell is made up of scutes, or horny plates made of keratin that act to protect the turtle.

As the turtle grows, these scutes will grow in an alternating pattern that forms visual rings on the turtle’s shell.

A turtle’s scutes will develop a new ring about every year, so you can usually determine how old a snapping turtle is based on how many rings are located on their shell.

However, growth rings often incorrectly age snapping turtles, especially those that are older, so it is not always a reliable method.

Carapace Ridges

Anyone that is familiar with snapping turtles will know that their shells are known for being smooth. However, their shells are not born like this.

When a snapping turtle is young, it will have three ridges found down the length of their carapace. After a few years, the ridges will disappear, leaving the turtle with its signature smooth shell.

So, if a snapping turtle does not have any ridges on its shell, you can be assured that it is likely a few years old at least.

Erosion

Contrary to what you would think, an older turtle’s shell will look nicer and more “polished” than that of a younger turtle. Because older turtles have spent their lives roaming over rocks and wood, their shells have been worn smooth and produce a shiny sheen.

Alternatively, turtles that are young have not worn down their shells, so they appear more ragged.

How Fast Do Alligator Snapping Turtles Grow?

Similar to common snapping turtles, the alligator snapping turtle growth rate is 1-2 inches a year when they’re juveniles.

Not much is known about the difference between how fast common and alligator snapping turtles grow. It is likely that alligator snappers grow similarly to alligator snappers, with their growth slowing down as they age.

How Big Do Snapping Turtles Get?

Snapping turtles can grow quite large, and are the biggest freshwater turtle species in North America.

In general, the common snapping turtle size will be about 15-19 inches long as an adult. They can also reach up to 60 pounds.

The largest recorded common snapping turtle was 19.5 inches long and 86 pounds in weight.

The answer to how big does a snapping turtle get and how long it takes them to grow also depends on where the turtle lives.

A snapping turtle’s growing season occurs during the warmer months. They hibernate when the weather becomes too cold, so they don’t grow during the winter months.

So, turtle’s living in warmer areas of North America will grow more quickly than those in colder regions.

How Big Do Alligator Snapping Turtles Get?

Although alligator snappers are similar to their common snapping cousins, they look more rugged and grow to be much larger.

So, how big can an alligator snapping turtle get?

Male alligator snapping turtles can reach lengths of up to 29 inches and weigh up to 249 pounds. Females are capable of reaching up to 22 inches in length and 62 pounds.

Generally though, males will reach about 175 pounds in weight and females will be about 50 pounds.

Unlike the common snapping turtles, females stay significantly smaller than their male counterparts.

How Does Age Impact The Size Of Snapping Turtles?

Generally, when a turtle is still quite young, it will grow about 3 inches per year. Once they become more mature and are reaching adulthood, they continue to grow, only slower. At this age, they will only grow about 1 inch per year.

On average a full-grown adult male will reach between 10 and 12 inches, while a full-grown female will reach 12-14 inches.

Here is a chart examining the average size of snapping turtles based on age:

1 Year3-4 Inches
2 Years5-6 Inches
10 Years7 Inches
25 Years11 Inches
70-100 Years18 Inches
SNAPPING TURTLE SIZE AGE CHART (IN INCHES)

How Does Diet Impact Snapping Turtle Growth Rate?

As with most animals, how quickly a snapping turtle grows is related directly to how much nutritional food they have access to.

Snapping turtles have individual scutes that make up the surface of their shells. These scutes will grow significantly larger and more quickly when there is plenty of food available to them.

Here are some of the best foods for a snapping turtle’s diet. When these are plentiful, a turtle will grow fast and large:

  • Meat (including fish)
  • Turtle pellets (if they’re being kept as a pet)
  • Insects
  • Worms
  • Fruits & veggies
  • Plants

Snapping turtles are omnivorous and are not picky. So, it is not usually hard for them to make sure they are receiving a full, nutritious diet.

The most important nutritional factor in ensuring that a snapping turtle grows steadily is protein. They need to eat plenty of foods rich in protein so they can grow healthy and strong.

Calcium is also vitally important in a snapping turtle’s diet because they need it to keep their shells healthy. Fortunately, there are plenty of fruits and vegetables rich in calcium.

Alternatively, they won’t grow very much if resources are scarce. Their growth rate will also decline the more they have to compete for food, or the more physically active their environment demands them to be.

How Long Do Snapping Turtles Live?

Like many species of turtles, snapping turtles can live for a long time, often longer than humans. Usually, snappers will live for at least 40 years, but some have been known to live up to 100 years.

The average lifespan of a common snapping turtle is between 50-75 years of age.

Alligator snapping turtles can live even longer. Their average lifespan is between 80-120 years of age, although it is thought that they can live up to 200 years.

Thunder, a snapping turtle that was housed at the Newport Aquarium in Kentucky was estimated to be 150 years old when she died.

Conclusion

Common and alligator snapping turtles are the largest turtles in North America, and they can live longer than most humans. Similar to how they can grow very large, they can also live a very long time.

Many things will determine how fast and large they can grow including their environment, how much sun they receive, and whether they are receiving proper nutrition.

Snapping turtles jaws and scaly skin are not the only things that make them intimidating. Their sheer size can rival that of a small child up to a grown adult.

I hope you have found this guide useful and it’s answered all your questions about how big are snapping turtles and how fast they grow.

Click here to read about the gestation period for snapping turtles and all about their eggs, here to read what baby snapping turtles eat or click here to find all out turtle guides. You can also read how big painted turtles get here.

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Jason Williamson

By Jason Williamson

Jason is a huge animal lover with many pets of his own. He loves sharing all his knowledge of all creatures here and learning more whenever he can.