How to feed your herbivorous tortoise.
All tortoises require a balanced diet. There are no ‘good’ or ‘bad’ foods as such. It is however very important to make sure that the animal has a variety of foods to eat just as with us a diet of only chocolate or lettuce would be unbalanced, but is not banned from the diet totally.
Tortoises have one of the highest concentrations of bone of reptilia, which means that their diet is based around providing sufficient Calcium and Phosphorous to provide a good skeleton. (See photo) Calcium and Phosphorous are required together to make bone along with Vitamin D3 that is most commonly obtained from natural sunlight or UV lights. The Calcium to Phosphorous ratio should be 2:1. Many foods do not have this ratio and so should be limited in the diet. Too much phosphorous in relation to the amount of calcium will have the effect of draining calcium from the bones.
This is one of the main reasons that herbivores should not be given meat or meat products, which contain high quantities of phosphorous, giving rise to pyramiding and soft shell in hatchling tortoises. Some foods can also affect the absorption of Calcium as they contain oxalates (Brussel Sprouts, curly Kale and Spinach), which can bind up some of the calcium present in the diet into a form that cannot be absorbed in the body.
The amount of calcium present in foods also depends on where it is grown. Those grown in limestone-enriched soil will contain more calcium than those in other areas.
Unlike mammals tortoises are unable to metabolize fat and if fed foods high in fat will store it under the skin and around vital organs such as the heart. Tortoises are unable to ‘diet’ and lose this fat so once there it stays and can cause long-term health problems.
Fat provides energy and Vitamins in the diet of mammals. Tortoises obtain vitamins from the fruit and vegetables in their diet requiring a wide variety to be fed.
Tortoises are vegetarian (i.e. herbivorous), and are able to obtain all the amino acids they require for growth and repair of body tissues by a varied diet. Amino acids are the building blocks for proteins, which form part of the cells of the body. Vegetables and fruit do not contain all the essential amino acids (i.e. those that cannot be manufactured by the body) in a single food like a portion of meat can, but one or more vegetables, and fruit, eaten together will provide all these essential amino acids. Vegans (a vegetarian who eats no animal produce including milk, cheese and eggs) just like tortoises need to eat a wide variety of fruits and vegetables. It is important to feed a variety of foods including a proportion of those vegetables and fruit high in protein such as peas, bananas, sweet corn and lentils, beans etc.
This Vitamin is essential for health of the mucous membranes of the body such as the eyes, mouth and skin and plays a part in night vision, the ability of tortoises to focus in poor light. Retinol (Vitamin A) is a constituent in the cones of the eyes, which help the eyes to adjust to low light. A lack of this Vitamin causes sore eyes and mouth; in severe cases the eyes become badly swollen and infected.
Success has been achieved in reversing temporary blindness caused by too low a hibernation temperature by the ingestion of large quantities of this Vitamin generally in the form of carrots.
All tortoises require water even though they may appear not to drink. A tortoise will invariably drink if sat in a bowl of water with the water deep enough to cover the head. Tortoises can only drink by putting their head under the water. Much of the water in the diet comes from the food they eat such as the salad vegetables and fruit. This should form part of the balanced diet.
An ideal way to think of the diet is in the form of a plate with different sections representing the amount of each type of food to feed.
Fruit contains vitamins and minerals especially Vitamin A (beta-carotene) in red/orange fruits. Fruits are also a good source of natural sugar in the form of fructose.
The vitamin and mineral content of fruits and vegetables change dependant on the season and the location where it is grown. It is therefore advisable to supplement the diet with vitamins and minerals. I use Nutrobal as it has the correct ration of calcium and phosphorous. Vionate is another alternative, but less specific to reptiles. I also supplement with calcium in the form of limestone flour.
These play a part in the diet as providers of Vitamins and minerals and, most importantly, water. They must however form only a small part of the diet, as a tortoise would need to eat very large quantities in order to achieve all the required nutrients. For example 2 round lettuces per day for a tortoise weighing 200g!!
Feeding at different times of the year
Tortoises are solar powered and eat much more when there is light and sun. During the summer months especially when it is hot feed your tortoises more. When Autumn and Winter begin then you will find your tortoise will gradually wind down and eat much less. If your tortoise will be hibernating and has gone off their food then making sure they have heat and light should encourage them to start feeding again. After the shortest day in December your tortoise will soon notice the lengthening day and begin to eat more readily. If your tortoise is a non- hibernator then do not worry too much if they go off their food for short periods during winter. Make sure they are warm enough and have water available. As they eat all year round they will come to no harm.
How often to feed?
Hatchlings generally need feeding every day especially when just hatched. Be wary of overfeeding your hatchling the volume of food should be about half the size of the animal with as mentioned earlier vitamins and minerals added. However Adult tortoises do not need to feed each day, they would not in the wild. Hibernating tortoises should be fed 5 times a week at least as they need to have put on sufficient weight to survive hibernation. The quantity to feed will depend on the amount of natural vegetation available to your tortoise in the garden. Tortoises will rarely overeat, the ones to be mindful of this though is the Horsfield tortoise.
Non – hibernating tortoises can be fed every other day. One can cause more problems nutritionally by overfeeding. If your tortoise eats everything within 2 hours of feeding and then offer more the next time.
Persuading the uni eater and breaking other bad habits in tort eating.
· Provide a variety of foods
· Limit high protein vegetables especially in hatchlings
· Remember to add calcium and vitamins
· Don’t over feed especially hatchlings
· Don’t worry if your tortoise stops feeding or eats less for a short while during winter time
· Always provide water
· Limit the fruit in the diet