Red-eared sliders are moderately sized turtles endemic to south-central United States. These turtles can get quite huge with age capable of reaching a carapace length of 16 inches and a weight of 3.2 kg. However, most individuals reach an adult carapace length of 6 to 8 inches with females being considerably larger than males.
So how fast do red-eared sliders grow? The short answer is quite fast. The species grows about an inch each year. The growth rate within the first year is the fastest.
From there, their growth rate is quite stable until they reach maturity. Upon reaching maturity, they continue to increase in size, although growth at this point is extremely slow.
What is the Red-Eared Slider?
The red-eared slider is actually a subspecies of Trachemys scripta (commonly known as pond sliders). Other pond sliders include the Cumberland slider and the yellow-bellied slider. The red-eared slider is easily identified by the red patch on the ears.
This turtle is endemic to the south-central United States. However, the species can be found throughout the entire United States as it is an invasive species in most states. In fact, it is an invasive species around the world.
As mentioned earlier the red-eared slider can reach a maximum carapace length of 16 inches (40 cm). This length is rare. Most red-eared sliders reach a length of 6 to 8 inches (15 to 20 cm). This makes the red-eared slider a moderately sized turtle. Similar to other emydids, adult females of the species are generally much larger than adult males.
Interestingly, the growth rate of males and females are the same. The difference is that males cease to grow once they reach age 5 while females continue until they are about 8 years. Individuals have been noted to keep growing until they are 15 years.
The species is known to reach a life span of 40 years in captivity, although a typical lifespan is 20 to 30 years. They grow fast for only about a fourth of their lives. For the rest of their lives after age 5 to 8, they barely grow.
The carapace of the red-eared slider is dark with the coloration ranging from dark brown to olive green. The species change color as they age. As hatchlings and juveniles, their carapace is leaf green. As adults, their shell is olive green to brown.
The shell is quite rough. The underside/plastron is yellow with dark markings that are mirrored on either side of the plastron.
The limbs, neck, head, and tail are dark green with yellow stripes. On each ear is a red stripe. These red stripes give the slider its common name.
It is a semi-aquatic reptile that makes its home in slow-moving freshwater bodies such as streams, swamps, rivers, ponds, and lakes. They also inhabit brackish water bodies such as lagoons. The depths of the water bodies that the slider commonly inhabits are 0.6 to 0.9 meters. They prefer slow-moving waters as they are able to easily get out of the water to bask.
This slider is predominantly omnivorous as juveniles and hatchlings. Once they reach maturity, they become more herbivorous. In the wild, their diet is an essential component of their growth rate. Juveniles with limited access to animal prey grow slowly. For the juvenile to grow at an optimal rate, its diet needs to include a large portion of protein.
The Growth Rate of Red-Eared Sliders
The growth of juveniles happens in annual stages with an increase in the layers of scutes that develop. With each passing year, a new scutes layer develops under the old layer. This layering allows you to determine the age of the juvenile as long as they are not above 4 years. This is because wear makes it quite difficult to determine the age this way.
The turtle continues to grow until they reach reproductive maturity.
Upon hatching, the turtle is about 23 to 35 mm. This is about an inch in size.
The growth rate of wild red-eared sliders sampled at Dewart Lake, Indiana, USA (carapace length)
(source: https://www.herpconbio.org/Volume_13/Issue_3/Lewis_etal_2018.pdf)
The chart above shows the average/estimated growth curve of red-eared sliders sampled from Dewart Lake in Indiana.
As you can tell the growth rates of both males and females are similar for the first 5 years. From there onwards, males see very little extra growth while females continue to see significant growth until about age 8. As mentioned earlier, males reach maturity at ages 2 to 5 years while females reach maturity at ages 5 to 8. Once a red-eared slider reaches maturity, its growth rate slows down significantly as evidenced by the chart above.
Upon reaching maturity, the red-eared slider’s growth slows down. Both males and females continue to grow even after maturity although additional growth after reaching maturity is extremely slow.
The growth rate of wild red-eared sliders sampled at Dewart Lake, Indiana, USA (plastron length)
| Estimated Age in Years | Males | Females |
| 1 | 60.3 mm (2.37 inches) | 62.1 mm (2.44 inches) |
| 2 | 87.8 mm (3.46 inches) | 92 mm (3.62 inches) |
| 3 | 109.4 mm (4.31 inches) | 116.7 mm (4.59 inches) |
| 4 | 126.4 mm (4.98 inches) | 137.1 mm (5.4 inches) |
| 5 | 139.7 mm (5.5 inches) | 154 mm (6.06 inches) |
| 6 | 150.3 mm (5.92 inches) | 167.9 mm (6.61 inches) |
| 7 | 158.5 mm (6.24 inches) | 179.5 mm (7.07 inches) |
| 8 | 165.1 mm (6.5 inches) | 189 mm (7.44 inches) |
| 9 | 170.2 mm (6.7 inches) | 196.9 mm (7.75 inches) |
The plastron of the red-eared slider is smaller than the carapace. Regardless of this, it can be used to track the growth rate of the turtle. Above is a chart of the growth rate of red-eared sliders measured in Indiana.
As you can see, males and females are about the same sizes during the first 4 years. After the first 4 years, females continue to see significant growth while the growth of the male turtles slows down significantly. Females keep seeing significant growth until the ninth year.
- At age 1, both males and females have a plastron length of about 2.4 inches.
- At age 2, males grow by about 1.09 inches and females grow by about 1.18 inches.
- At age 3, both males and females grow by about 1 inch. At age 4, males grow by about 0.7 inches and females grow by about 0.9 inches.
- At age 5, males grow by about 0.5 inches and females grow by about 0.7 inches.
- At age 6, males grow by about 0.4 inches and females grow by about 0.6 inches.
- At age 7, males grow by about 0.25 inches and females grow by about 0.45 inches.
- At age 8, males grow by about 0.25 inches and females grow by about 0.37 inches.
- At age 9, males grow by about 0.2 inches and females grow by about 0.31 inches.
As you can tell, the growth rate of the males is slower than that of the females.
(source: https://www.herpconbio.org/Volume_13/Issue_3/Lewis_etal_2018.pdf)
The growth rate of red-eared slider turtles is similar in captivity with females reaching a larger size than males although the growth rate during the earlier parts of the species’ lives is similar.
Below is the estimated growth rate of red-eared sliders in captivity.
| Estimated Age (years) | Males’ average Carapace Length | Females’ average CarapaceLength |
| 1 | 1.6 inches (4 cm) | 1.6 inches (4 cm) |
| 2 | 2.4 inches (6 cm) | 2.4 inches (6 cm) |
| 3 | 4 inches (10 cm) | 4 inches (10 cm) |
| 4 | 4.5 inches (11.5 cm) | 4.5 inches (11.5 cm) |
| 5-6 | 6 inches (15 cm) | 6 inches (15 cm) |
| 6 to 8 | 6 inches (15 cm) | 8.5 inches (21.6 cm) |
| Over 8 | 6 inches (15 cm) | 9.5 inches (24.1 cm) |
Here both males and females grow at the same rate as expected but by age 5 to 6 years, males remain about the same size while females continue to grow.
Factors that Influence Growth Rate
The speed at which a turtle grows is influenced by several factors. Of course, the individual genes of the turtle play a major [art om determining how fast a turtle grows. Apart from that factors such as diet and the general care of the slider plays a large part in the growth rate of the turtle.
As far as you are taking good care of your red-eared slider, you needn’t worry too much about the growth rate of the turtle. The growth rate is also a good indicator in estimating the age of the turtle.
Diet
Both in the wild and in captivity, the diet of the growing turtle influences how fast the turtle grows. Juveniles and hatchlings are omnivorous but mostly feed on animal material. This includes reptiles, amphibians, slugs, sponges, clams, snails, crayfish, fish, and other insects. They even feed on carrion.
However, on occasions where there isn’t an adequate amount of animal prey, the juvenile will be forced to eat a plant-based diet. This leads to slow growth and even death. This shows that the turtle’s diet plays a major part in the growth rate.
There is a reason why juveniles prefer a protein-based diet. Unlike adults, juveniles lack the microflora in their digestive system that breaks down tough plant materials.
In captivity, the diet of the red-eared slider contributes to healthy growth. The diet offered to the turtle should be high in protein. Protein sources include commercial turtle diet, insects, fish, shrimps, and other small animals.
Age
The age of the turtle is an important determinant of how fast the turtle grows. As mentioned earlier the older the turtle is the slower it grows. Between ages 0 and 5, the turtle grows the quickest. After that, the growth rate slows and eventually plateaus.
If your red-eared slider is less than 5 years, expect it to grow about an inch in carapace length each year. Females will continue to have a steady growth rate until about age 8.
Sex
While the growth rate of males and females are similar at a younger age, males see a slowdown in growth much earlier than females. At age 5, most males grow really slowly. Females on the other hand see significant growth until ages 8 to 9.
Frequently Asked Questions
How quickly do red-eared sliders grow?
Upon hatching, the turtle is about an inch in size. Within the first few years, the turtle grows about 3 inches. That is an average of about an inch each year. The turtle continues to grow at this rate until it is 5 years old. While males generally stop growing at this age, females keep increasing in size until it is about 8 years old.
At what age do red-eared sliders mature?
Males mature at ages 2 to 5 years and females mature at ages 5 to 7 years.
Can you put two red-eared sliders together?
Yes, you can as long as the conditions are right. If you wish to house two red-eared sliders in the same enclosure ensure that it is large enough.
A large enclosure ensures that the two turtles do not get in each other’s way. As a rule of thumb, you should provide about 10 gallons of water per every inch. As per the rule, you should house a 5-inch turtle in a minimum of 50 gallons of water. For each additional turtle, add about 5 gallons of water for each inch.
How long does it take for a turtle to grow full size?
Males reach their full size at about age 5 and females reach their full size at about age 8. Both males and females will see a marginal increase in size until they die.
How long does a red-eared slider live?
Red-eared sliders can live to 41 years although on average most sliders kept as pets live to 20 to 30 years with proper care.
Conclusion
Red-eared sliders are among the most popular pet turtles in the world. Their care requirements are relatively easy to meet. Compared to other turtles commonly kept as pets, they are interactive.
So how fast do red-eared sliders grow? These turtles grow about an inch each year until they reach maturity. Males reach maturity at age 5 and females reach maturity at age 8.
Upon hatching, the turtle is about an inch in carapace length. As such, the average carapace length of males at maturity is about 6 inches. For females, the average carapace length at maturity is about 8 inches.
Some individuals can reach over a foot in carapace length and a weight of about 3.2 kg or 7 pounds.