Turtles are fascinating creatures that come in all shapes and sizes. If you’re a turtle owner, you may be wondering: can turtles eat grass? Grass is everywhere, so it seems like an easy food source. However, the answer isn’t so straightforward.
While some turtles occasionally nibble on grass, it’s not nutritionally ideal as a staple in their diet. Read on as we take a deep dive into the diets of different turtle species and whether grass should be on the menu.
If you’re short on time, here’s a quick answer: Most turtles cannot digest grass well, so it should not make up a significant portion of their diet. Grass lacks the nutrition turtles need. Still, some grazing is normal for many species.
An Overview of Turtles and Their Diets
Turtles Are Omnivores
Turtles are omnivores, meaning they eat both plant and animal materials (1). Most turtles eat a combination of aquatic vegetation, insects, small fish, worms, and amphibians. Their diverse palate allows them to obtain all the nutrients they require from readily available food sources in their habitats.
Certain turtle species do specialize in specific foods depending on the structure of their mouth and habitat. For example, sea turtles have pointed beaks ideal for catching fish and jellyfish, while box turtles have broad, sturdy beaks for crushing and mashing up vegetation (2).
But overall, the majority of turtles are opportunistic omnivores.
Turtles Require Calcium and Vitamin A
To stay healthy, turtles need diets rich in calcium and vitamin A. Calcium is essential for proper bone and shell development. Vitamin A maintains eye, skin, and immune health (3). Most turtles get adequate amounts of these nutrients by eating greens, small fish with bones, and aquatic plants.
Calcium deficiency can cause shell deformities, fractures, and metabolic bone disease. Vitamin A deficiency leads to respiratory infections, eye problems, and poor wound healing. Providing turtles with nutritionally balanced, varied diets prevents these issues.
Grass Has Limited Nutritional Value for Turtles
Grass does contain small amounts of calcium, protein, and vitamins. But its fibrous content makes it difficult for most turtles to digest properly. As herbivores, tortoises can process and extract nutrients from grass. But for other turtle species, grass offers very limited nutritional benefits (4).
In fact, grass can pose dangers for aquatic and omnivorous turtles. The fibers can obstruct the digestive tract, leading to impactions. And pesticides and fertilizers in grass can also be toxic. It’s generally best to avoid feeding grass to aquatic or box turtles.
Occasionally sampling tender grass shoots is usually fine. But grass should never make up a substantial portion of other turtle species’ diets. They require more nutrient-dense foods like aquatic plants, vegetables, insects, and fish.
Which Turtles Can Eat Grass?
Tortoises Graze on Grass
Tortoises, which are land-dwelling turtles, are known to graze on grass and weeds as a major part of their diet. Many tortoise species are herbivores, meaning they only eat plant materials. Grass provides tortoises with fiber and nutrients like vitamin A, vitamin C, and calcium.
Popular pet tortoises like the Russian tortoise, Greek tortoise, and African spurred tortoise enjoy grazing on fresh grasses when housed outdoors. In fact, access to grass is crucial for a tortoise’s health!
Tortoises use their beak-like jaws to bite off and chew up blades of grass. They are grazers by nature and will leisurely munch on grass throughout the day. A tortoise’s digestive system is designed to break down the cellulose in grass and plants.
Backyard tortoises may graze on Bermuda grass, Timothy grass hay, dandelion greens, and clover.
Aquatic Turtles May Nibble on Aquatic Plants
Most aquatic turtle species are omnivores, meaning they eat both plant and animal materials. Aquatic plants make up a smaller portion of their diet compared to land turtles. Some aquatic plants and algae that aquatic turtles eat include:
- Duckweed
- Elodea
- Water hyacinth
- Water lettuce
- Green algae
Turtles like red-eared sliders may nibble on aquatic plants when their normal protein sources like worms or small fish are scarce. But their digestive systems aren’t designed to extract nutrients from fibrous plants as efficiently as herbivorous tortoises.
Too much plant material can lead to gastrointestinal issues in aquatic turtles.
Grass Should Be a Small Part of Most Turtle Diets
While tortoises thrive on diets high in grass and leafy greens, most other turtles should only eat grass occasionally. Aquatic turtles especially rely more heavily on proteins from fish, insects, worms, and invertebrates. Here’s a quick rundown of grass in the diet for different turtle groups:
| Turtle Type | Can They Eat Grass? |
|---|---|
| Tortoises | Yes, grass should be 70-90% of diet |
| Semi-aquatic turtles | Occasionally, up to 10% of diet |
| Aquatic turtles | Rarely, only a small portion |
While tortoises thrive and depend on grasses, most other turtles will just nibble on grass. Grass provides some nutrients but too much can prevent proper growth and shell development in young turtles especially. Varying the diet according to turtle type is crucial.
Providing a Healthy, Balanced Diet for Your Turtle
Leafy Greens and Vegetables
Turtles enjoy a varied diet rich in leafy greens and vegetables. Some nutritious options include kale, collard greens, turnip greens, mustard greens, bok choy, green beans, squash, carrots, and sweet potatoes. These foods are loaded with beneficial vitamins, minerals and antioxidants.
According to the My Turtle Cam site, vegetables should make up 25-50% of your turtle’s diet.
Quality Turtle Pellets and Foods
In addition to fresh vegetables, commercially available turtle diets can provide balanced nutrition. Look for high-quality pellets and foods designed specifically for turtles, containing 25-35% protein. Top turtle food brands vetted by keepers include Zoo Med and Mazuri.
These foods deliver nutrients absent from an all-vegetable diet, like vitamin D3 for healthy shells.
Certain Fruits as Occasional Treats
While vegetables form the foundation of healthy turtle meals, certain fruits can occasionally be offered as treats. Good options include strawberries, blueberries, cantaloupe, grapes and bananas. Just be sure to limit fruit to once a week at most, since they are high in sugar.
Too much can cause diarrhea. Chop fruits into bite-sized pieces for easy eating.
Protein Sources Like Worms and Shrimp
While commercial turtle foods contain protein, offering worms, shrimp, feeder fish or other natural protein sources also benefits your turtle’s health. Varying protein types enhances nutrition. A general rule is to keep animal-based proteins to under 10% of total food volume.
Great protein options include mealworms, earthworms, crickets, river shrimp and guppies. Prior to serving, rinse, chop or soften foods for safety.
When Grass-Eating May Be Harmful for Turtles
Risk of Pesticides and Chemicals
Grass that has been treated with pesticides or chemicals can be extremely dangerous for turtles to consume. Many common weed killers, insecticides, and fungicides are highly toxic to reptiles. Even small amounts can cause poisoning, organ damage, neurological problems, and death.
Turtles ingest these chemicals both by directly eating treated grass and by consuming insects that have come in contact with treated lawns. According to the journal Science of the Total Environment, some commonly used lawn care products like 2,4-D and glyphosate show moderate toxicity in painted turtles.
Exposure to these toxins can also have chronic effects over time. Research from the University of Georgia found increased levels of organochlorine pesticides stored in the fat and eggs of slider turtles living in areas with chemical lawn treatments.
This build up of toxins can suppress the immune system, impair reproduction, and lower egg viability. Ultimately, pesticides and weed killers can pose a significant threat to turtle populations in suburban areas.
To keep pet turtles safe, never allow them to graze on grass that has been treated with any lawn chemicals. Always check for warning signs after chemical application before allowing access. Opt for natural weed and pest control methods like vinegar or hand picking weeds whenever possible.
Can Prevent Eating More Nutritious Foods
While grass provides modest nutritional value, a diet too high in grasses can lead to malnourishment in turtles. Grass is low in protein and fat compared to greens, vegetables, insects, fish and other more optimal turtle foods.
Grass also contains insoluble fiber that can decrease absorption of nutrients.
If grass makes up too much of a turtle’s diet, they may fill up on the low calorie fiber without getting the vitamins, minerals and macronutrients essential for their health. This can slow growth in juveniles, impair egg laying in females, or lead to nutritional deficiencies.
According to the Maryland Zoo, side-necked turtles, box turtles, and aquatic species have the greatest need for protein and calcium. These turtles should get most of their nutrition from quality turtle pellets, leafy greens, small fish, worms and other insects.
Grass should only be a supplemental part of a varied diet. Always provide high quality turtle food at each feeding time before offering grass.
Indigestible Fiber and GI Upset
The insoluble fiber found in most lawn grasses is indigestible for most turtles. Soluble fiber can be fermented by gut bacteria into usable energy. However, insoluble fiber passes through undigested, absorbing water along the way.
This extra fluid in the intestines can lead to loose stools or diarrhea in some turtles.
Too much grass may also create a bowel obstruction if large clumps accumulate. According to the journal Comparative Biochemistry and Physiology Part A, grass can make up a large portion of gut contents in wild turtles.
However, meat and insects were more digestible while grass provided little usable nutrition.
Monitor your turtle’s stool if offering grass. Watery, loose, or obstructed bowels may indicate too much grass consumption. Slowly cut back on grass while providing more digestible foods.
Grass still provides enrichment and grazing satisfaction for many turtles. Just feed in moderation alongside a varied, nutritious diet to avoid adverse effects on digestion.
Conclusion
While most turtles will occasionally nibble on grass, it does not provide ideal nutrition. Tortoises and some aquatic turtles may graze more frequently, but too much grass can lead to an imbalanced diet. Providing leafy greens, vegetables, quality pellets and protein sources is key.
Limit grass to a minimal part of your turtle’s diet to keep them happy and healthy.
