Map Turtle
The northern map turtle (Graptemys geographica), once called the common map turtle, is a freshwater turtle from eastern North America. It gets its name from the thin yellow lines on its shell, which look like the lines on a map. Map turtles are shy baskers that spend most of their lives in large rivers and lakes.
Scientific Classification & Quick Facts
| Common name | Northern map turtle |
| Scientific name | Graptemys geographica |
| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Testudines |
| Family | Emydidae |
| Genus | Graptemys |
| Conservation status | Least Concern |
| Type | Reptile (freshwater turtle) |
| Diet | Omnivore: crayfish, snails, insects and water plants |
| Habitat | Lakes, rivers and ponds with plants and basking logs |
| Native range | North America |
| Special feature | Males flutter their long front claws at the female’s face |
What Map Turtles Look Like
The shell, or carapace, is olive to brown with a network of thin yellow or orange lines. There is a low ridge, called a keel, running down the middle of the back. The skin is dark with yellow stripes, and there is often a small yellow spot behind each eye.
Females are much bigger than males. Adult females can grow to about 18 to 27 cm (7 to 10.5 inches) long, while males usually stay around 10 to 16 cm (4 to 6 inches). Females also have very large heads and powerful jaws for crushing shells, while males have smaller heads and longer, thicker tails.
Where They Live
Northern map turtles live in the Great Lakes and St. Lawrence River region and through much of the Mississippi River basin, from southern Canada south to states such as Arkansas, Tennessee and Alabama.
They prefer large, slow-moving rivers and big lakes with soft bottoms, plenty of water plants and lots of fallen trees and rocks to bask on. Map turtles are famously wary: at the first sign of danger, a whole log of basking turtles will slide into the water.
In the colder parts of their range, they spend the winter underwater on the bottom of rivers and lakes. Their bodies slow down so much that they can take in oxygen from the water while they rest.
Diet
Map turtles are mostly carnivores, though they eat some plants. In the wild, females use their strong jaws to crush snails, clams and mussels, including invasive zebra mussels. Males and young turtles eat more insects, larvae, small crayfish and other soft prey.
In captivity, they can be fed a good-quality commercial turtle food along with treats such as small snails, earthworms and insects, plus some leafy greens or water plants.
Breeding
Map turtles mate in the water in spring and autumn. During courtship, the male swims in front of the female and bobs his head and drums his front feet near her face.
From about May to July, females climb onto land to lay their eggs. They choose open, sunny spots with sandy or soft soil and dig a nest, usually laying around 10 to 15 eggs. The temperature of the nest decides whether the babies will be male or female: warmer nests produce more females. Hatchlings appear in late summer, though in the north some stay in the nest until the next spring.
Map Turtles as Pets
Map turtles are sometimes kept as pets, but they are not easy beginner turtles. They can live for decades, need a lot of space, and are sensitive to dirty water. Pet turtles should always come from captive breeders, never from the wild, and it is important to check local laws first.
Tank Setup
Because wild map turtles live in clean, flowing water, they need excellent filtration in captivity. A couple of hatchlings can start in a 20-gallon long aquarium, but they grow quickly, and a single adult female needs a tank of around 75 to 125 gallons or more. Choose a filter rated for a much bigger tank than the one you have, and change part of the water regularly.
Map turtles can be pushy as they grow. Bigger turtles, especially females, may bully smaller ones. Adding rocks, plants and more than one basking spot gives everyone space and reduces fighting.
Basking, Heat and Light
Map turtles love to bask, so they need at least one large, dry basking platform under a heat lamp. They also need a UVB light, which helps them use calcium and keeps their shells healthy. The water should be kept comfortably warm, around 22 to 25°C (72 to 77°F), with the basking spot warmer.
Outdoor Ponds
In suitable climates, map turtles do very well in secure outdoor ponds during the warm months. Do not overcrowd the pond. Floating plants such as duckweed, water lettuce and water hyacinth provide shade and cover and help keep the water clean, but some of these plants are invasive, so only use them where they are allowed. Northern map turtles can hibernate in deep ponds, but this needs careful planning, and many keepers bring their turtles indoors when temperatures drop below about 7 to 10°C (45 to 50°F).
Health
Most health problems in pet map turtles come from poor water quality, too little basking, or a lack of UVB light. These can lead to soft or damaged shells, shell rot, fungal infections of the skin and respiratory infections. Strong filtration, clean water, a warm basking area and good lighting prevent most of these problems. If your turtle stops eating, has swollen eyes or seems weak, take it to a vet who treats reptiles.
Handling
Map turtles are better for watching than for handling. If you need to pick one up, hold it gently by both sides of the shell. Never pick a turtle up by its tail or legs, never turn it on its back, and do not poke its head to make it hide. Their claws can be sharp, so be careful.
Like all reptiles, turtles can carry Salmonella germs, so always wash your hands with soap and water after touching a turtle or anything in its tank.
Northern map turtle FAQs
Why is it called a map turtle?
Map turtles are named for the lines and markings on their shells that look like the lines on a map.
What do map turtles eat?
They eat both animals and plants. In the wild they eat crayfish, hard-shelled snails and many insects, and their jaws become big and strong from crunching shells. Young ones eat more plants.
Where do map turtles live?
The northern map turtle lives in North America in lakes, rivers and ponds with lots of water plants. It likes places with fallen trees and logs for basking.
How do male map turtles court females?
The male faces the female and vibrates his long front claws against her face to persuade her to mate.
When do map turtles nest?
They nest in May and June, laying eggs in dry, sandy, sunny places. They mate mostly in deep water in spring and fall.
Randi Jones is the owner and founder of the Nature Gift Store, an online retailer specializing in nature-themed gifts, educational science projects, live animal nature kits and real butterfly artwork. A biology graduate who fell in love with insects, she founded the company in 2001 to make active learning about nature fun, accessible and engaging for children and adults. Her store offers real butterfly frames, home and garden decor and educational live animal kits, including ant farms, worm farms, tadpoles, ladybugs and hermit crabs, and she runs a bug museum in Washington featuring live animals like Eddie the Iguana alongside other reptiles and insects.
