How Big Do Turtles Get?

By Teresa Traverse

If you’re considering buying a pet turtle, one of the biggest questions you’re probably asking yourself is how big your new pet will get. This is one of the most important questions you can ask, as turtles can vary greatly in size depending on their species and type.

Some turtles can weigh less than a penny at birth, said Laurie Hess, DVM and owner of the Veterinary Center for Birds and Exotics Bedford Hills, New York, while other species can grow to weigh several hundred pounds. Before you purchase your turtle, research your species to get an idea of how big your turtle will get and keep the following tips in mind.

Expect Slow Growth

Many turtle owners want their turtles to grow large quickly, but this is not a realistic expectation, said Jay Johnson, DVM and owner of Arizona Exotic Animal practice and consultant for the Arizona Game and Fish Department and U.S. Fish and Wildlife service on tortoise-related health issues. “They’re designed to grow very slowly,” Johnson said. “People want them to grow big and fast. But that’s not always healthy.”

Factors that can affect the size of your turtle include how much UV light (sunlight) it receives, temperature and drought conditions, as well as how sound its nutrition and diet is. 

Common Turtle Species and How Much They Weigh

Here are the size expectations for the most common turtles (including turtles kept as pets):

• Western painted turtles: painted turtles are “painted” red, yellow and olive, making them one striking species. They range in size from four to ten inches.
• Red-eared sliders: according to Johnson, these are the most common aquatic turtles and can range in size from 5 to 12 inches (with females being typically larger than males). Red-eared sliders can live up to 30 years.
• Eastern box turtles: as their name suggests, Eastern box turtles are native to the Eastern part of the United States and range in size from four to eight inches. In the wild, they can live up to 100 years.
• Texas map turtle: sensitive to water quality, Texas map turtles must have a spot to bask if kept as a pet. They can range in size from 2.75 to 8.5 inches.
• Wood turtles: this species’ habitat should also include access to both water and dry land. Wood turtles can grow up to nine inches.

Setting Up a Good Habitat

One of the most important parts of turtle care is providing an appropriate environment where your turtle can live and grow naturally. Once you know approximately how large your turtle will get, you’ll want to purchase an environment that can accommodate your pet and, if possible, go big. “The more space, the better,” Johnson said. “Most people don’t provide nearly enough space.”

Johnson recommends researching your turtle’s natural habitat and trying to mimic that as best you can. For instance, if the turtle hibernates throughout the year, you should try to recreate that experience. Consider using a kiddie pool or habitat you can build yourself over glass aquariums, which are heavy and can be challenging to clean, he said. Once you’ve set up your turtle’s habitat, you’ll want to fill it with the following:

• A UV light
• A heat lamp
• Substrate or the material where the animal lives. Materials for this can include woodchips, sand, dirt and coconut fiber. Try to keep food out of the substrate so that your turtle doesn’t ingest the bedding
• A wooden log (periodically moisten with water to provide the turtle with some kind of humid environment where they can hide).

Consider placing the UV light—which simulates sunlight—on one side and the heat lamp on the other so the turtle can spend time in both environments. Many turtles like to bask in the sunshine. Don’t allow plastic, plexi-glass or glass to be underneath the UV light.

When it comes time to clean the habitat, remove everything, throw out the old substrate and replace it with new materials. Wipe down everything with a very dilute bleach solution, let it dry for ten minutes and rinse it before putting everything back in. How often you clean depends on the type of tank. If it’s a moist environment, you may need to clean twice a month. If it’s a dry one, you could clean once every few months.

Image: Adam Van Spronsen / Shutterstock