During one of the visits to our local zoo, I heard our guide say that not all vegetables are safe for tortoises to eat since some contain compounds that can be harmful to tortoises. With this in mind, I did some research to find out if kale is among these vegetables.
Can tortoises eat Kale?
Tortoises can eat kale, in fact, kale is a good source of calcium for all species of tortoises. The oxalic level in kale is not high enough to be toxic to tortoises. Kale also has goitrogens that can interfere with iodine uptake. However, kale compensates for this effect by having high levels of iodine.
A healthy tortoise diet should have high levels of fiber, calcium, vitamins, and low protein. Vegetables, greens, and fruits are good sources of vitamins but should be fed sparingly since they lack minerals. The high sugar content of fruits makes them unsafe for non-fruit-eating tortoises such as Mediterranean and Grazing tortoises especially when they are fed in excess.
Vegetables and greens have compounds such as goitrogens that are harmful to tortoises’ thyroid glands, liver and kidneys when fed in excess.
Therefore, to be on the safe side always ensure you know how to identify the species of your tortoises and what should make up a large part of their diet.
As a quick note, fruits, vegetables, and salads should be fed sparingly, much of the diet should be foods high in fiber such as grass and hay. You can also offer high-quality commercially made tortoises pellets such as these ones from Amazon that are made with the nutritional needs of tortoises in mind.
The tables below shows different types of tortoises and what they should eat.
|Greek Tortoises, Spur Thighed (Testudo Graeca)
|100% variety of weeds and flowering plants
|Hermanns tortoise (Testudo Hermanni)
|Limit or avoid: Fruits, vegetables, and salads
|Marginated Tortoise (Testudo Marginata) and the
|Russian / Horsefield (Testudo Horsefieldi)
|Egyptian Tortoise (Testudo kleinmanni)
For Mediterranean tortoises most experts recommend against feeding fruits at all since their digestion system is not designed to deal with the high sugar content of fruits. However, when fed moderately this species of tortoises can feed on fruits.
Rainforest Tortoises/ Fruit-eating Tortoises
|70% weeds, flowering plants, and other greens
|Yellow footed tortoises [Geochelone denticulata]
|30% Fruits and a small amount of animal protein
|Burmese Brown Tortoises
|Kinixys homeana (Home’s Hingeback tortoise
This species of tortoises can comfortably eat fruits since they are found in the rainforest floors where they encounter fallen fruits that have a high concentration of sugar. Their digestion system is used to digesting the high sugar content of sugar and animal protein as they also eat carrion or dead animals in the animal floor.
|African Sulcata Tortoises
|70% mixed grass and Hay
|20-30% flowering plants, succulents and weeds.
|Limit or Avoid: Fruits, vegetables, and salads
These tortoises are found in the desert or grasslands areas, they should also either eat fruits sparingly or none at all since their digestion is not suited to digest the high levels of sugar in the fruits. Grass and succulents make up a large part of their diet in the wild.
Can tortoises eat kale and spinach?
While kale is safe for tortoises to eat, you should not feed tortoises kale and spinach combined in one feeding. Spinach has a high level of toxic oxalic acid that interferes with calcium absorption plus it also has goitrogens that can damage the thyroid glands, kidney, and liver.
Experts recommend avoiding or keeping to minimal vegetables that are high in oxalic acids and goitrogens and advocate for not feeding these vegetables together in one feeding session.
Is Kale Healthy for Tortoises?
As mentioned earlier kale is a very good source of calcium for tortoises and is completely safe and healthy for the tortoises to eat sparingly.
The table below shows the nutritional content of kale.
|Amount in 1 cup
|Carbohydrate in grams (g)
|6.3, including 1.4 g of sugar
|Calcium in milligrams (mg)
|Selenium in micrograms (mcg)
|Vitamin C (mg)
|Folate (mcg DFE)
|Beta carotene (mcg)
|Lutein + zeaxanthin (mcg)
|Vitamin E (mg)
|Vitamin K (mcg)
|Vitamin A (mcg RAE)
Benefits of Feeding Kales to Tortoises
Keeping Tortoises Hydrated
Tortoises should have easy to fresh, clean and chlorine free water on daily basis. Without water tortoises will suffer from dehydration that can lead to life threatening adverse effects.
While providing water to your tortoise in a bowl is a good way to keep them hydrated, tortoises also get water from the food they eat such as fruits and vegetables and other plant materials.
Kales have a high water content like most vegetables, you also sprinkle kale with water while feeding them to tortoises.
Water also help tortoises eliminate nitrogenous waste from the body, since accumulation of these wastes can cause health issues.
You can also read this post we wrote about the signs of dehydration in tortoises and how to easily dehydrate a tortoise.
Source of Vitamins
Vitamins forms a very important part of the nutrients that tortoises need in their diet on daily basis. One of the most important vitamin needed by tortoises is vitamin A.
Fruits and vegetables are a great source of vitamin A and its precursor beta carotene. A tortoise that eats a well-balanced diet with vegetables, fruits, and other plant materials will rarely suffer from vitamin deficiencies.
Vitamin A deficiencies include
- Swollen and inflamed eyelids
- Difficulties breathing
- the horny part of the skin thickens
- Abnormal development of the horny part of the mouth
- Liver failure leads to swollen limbs
- Weak immune system
Vitamin is a fat soluble vitamin meaning that when offered in high levels it can accumulate in the liver and become toxic a condition known as hypervitaminosis.
A balanced diet which does not involve feeding same vegetable or fruit food item will prevent such a complication from happening.
The table above shows other vitamins that kale provides to tortoises, these vitamins are either digested from the tortoises gut or kidney and deficiencies are rare. They are also water soluble which means they are normally excreted through urine when they are in high levels, to avoid toxicity.
Like vitamins minerals are equally important to tortoises growth and development. Minerals are the building blocks of the tortoises skeleton and shell.
Poor or insufficient supply of minerals in the body of tortoises can easily lead to bone fructure or deformed shell.
Calcium and phosphorus are some of the most important minerals that tortoises require for growth and development.
While vegetables are not a good source of minerals, kale is an exception and has a good level of calcium. However, it is important to note that calcium and phosphorus affect each other differently, high phosphorus levels hinder the absorption of calcium.
As a result, experts advice that the level of calcium should be twice the level of phosphorus in a food item to allow proper absorption of calcium. The recommended ratio is 2:1 calcium to phosphorus respectively.
However, for food items that do not observe this rule, they can still be fed to tortoises sparingly.
Kales’ calcium to tortoises is within the acceptable range. Laying, injured or young tortoises need more calcium compared to tortoises that are generally healthy.
How to feed kale to tortoises
- Like all vegetables and greens plus salads, organically grown ones are the safest
- Thoroughly wash the spinach
- Mix it with other vegetables
- you can also dust it with mineral supplements
Vegetables are best offered in the morning with the tortoises’ hay and grass so that they can feed on them the whole day.
Can kale harm tortoises?
As stated earlier, kale has a compound known as oxalate that impairs the absorption of calcium. However, the oxalate levels in kale are not much [about 20g in 100g of kales]. They can only become toxic when kale is fed excessively or when it is fed together with other vegetables that have a high level of oxalates such as spinach.
Addittionally, kale also has goitrogens, goitrogens affect the thyroid glands and interefere with the absorption of iodine. Goitrogens also damage kidneys and liver when they are in high levels.
However, the goitrogen levels in kale are not substantially high and the iodine content in kales compensates the iodinine lost as a result of kales.
However, experts recommend to avoid feeding a lot of vegetables that have high goitrogens and oxalic acids at the same time, so as to avoid the accumulation of these toxic compounds to levels that the tortoises cannot handle.
Can Russian Tortoises eat Kale?
Hermann and Russian tortoises can eat kale moderately. Kale have a high level of calcium needed for the healthy growth of the tortoises bones and shells. However, Russian tortoises should have kale moderately to avoid accumulation of oxalates and goitrogens found in kale that can be toxic to all tortoises.
Vegetables are a good source of vitamins and water for tortoises. However, kale doubles as a good source of vitamin A and calcium. You should however, make sure that the bulky part of your tortoises diet consists of fiber, calcium and low proteins. Vegetables and fruits should just be part of treats for your tortoises but the main diet apart from the rainforest or tropical trotoises that can deal with the high sugar content of fruits.