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The Tlady's Guide
GUIDE INTRO | IN THE WILD | ACCOMMODATION | DIET |

THROUGH THE YEAR | ADULT TORTOISES

 

Diet & Healthy Growth

Resist the temptation to overfeed; feed the right diet (see food plant list) but not too much of it!

Tortoises have evolved to thrive in subsistence conditions in hot, dry places where vegetation is often very sparse. They eat morning and evening, sleeping during the hot part of the day; in the wild they are not constantly woken up and offered heaps of succulent food! They have to walk and scramble as they search for food plants, biting off flowers and leaves as they travel, hence they use energy and develop muscle. The growth rings on a wild tortoise are even and flush with the curve of the shell and the scutes form one smooth overall dome shape without 'bumps'.  

If overfed, even on a good wild diet, the growth will be too rapid, growth rings will be raised and the shell become peaky (known as pyramiding). Much worse, on an incorrect diet including such unnatural items as dog and cat food, cheese, bread, cornflakes, etc., (never encountered in the wild!) a tortoise will be a very sorry animal; soft shelled, deformed and weak and with potentially fatal kidney and liver problems. Metabolic bone disease (MBD) is a common cause of captive reptile fatalities and is caused by insufficient Calcium being laid down in the bones (see section on Calcium and Vitamin D3).  
The diet should be vegetarian, adequate in moisture, high-fibre, vitamin and mineral rich, low-fat and low-protein - so even high protein vegetables should be avoided (e.g. peas, sweet corn, bean sprouts) to achieve a gradual, even shell growth.  
Many of the plants on the following Food Plant List are relatively high in calcium, vital for forming shell and bone and this should be supplemented with and a daily dusting of calcium and a suitable vitamin and mineral supplement such as Vionate, Nutrobal, or Repcal, plus cuttlefish bone (sharp edges removed) which they will bite at if they need it

Growth rate  

The rate of growth can vary a lot between individuals, even within the same clutch, but a rough, ‘handy’ size guide is:-

1 year - length of little finger

2 years - length of ring finger

3 years - length of middle finger

5 years - length of palm

10 years old - length of hand

Don't try to grow them faster! Aim for a slow, even growth like the wild ones.

Click for: How to measure a tortoise

If they have a good variety of wild food plants to graze on there is no need to add any extra, if not, feed them in the morning when they have basked in the sun and become active, and again in the mid to late afternoon after their siesta.  
It is useful to weigh the growing youngsters regularly to build up a record of growth patterns and alert you to unusual weight fluctuations which could signal poor feeding or dehydration. Don't panic though - a ‘poo and a pee’ can make a big difference to a juvenile's weight.

Food Plant List

This is based on my observations of plants eaten by tortoises both in the wild and in English gardens. It includes plants from a variety of botanic families to ensure a good balance of nutrients, vitamins and minerals and to avoid 'dependence' on a single food.  

Click on the Latin names to view the illustrations and notes, or click to use the Quick Browse gallery

Dandelion Taraxacum officinale  
Hawkbits & Cat's-ears Leontodon & hypochoeris spp
Hawk's-beards Crepis biennis & capillaris
Orange Hawk's-beard (Fox & Cubs) Pilosella/Hieracium aurantiacum
Nipplewort Lapsana communis  
Chicory Cichorium intybus
Sow thistle Sonchus oleraceus & arvensis
Plantains Plantago major, media & lanceotata
Mallows Malva sylvestris, neglecta & moschata 
Shepherd's purse Capsella bursa-pastoris
Bittercress Cardamine hirsuta & flexuosa
White/Dutch clover Trifolium repens
Red clover Trifolium pratense
Common vetch Vicia sativa  
Bush vetch Vicia sepium
Tufted vetch Vicia cracca
Sainfoin Onobrychis sativa
Creeping Bell-flower Campanula rapunculoides
Evening primrose Oenothera biennis
Bindweeds Convolvulus & calystegia spp
Stonecrops Sedum album & spectabile
Hedge mustard Sisymbrium officinale
Honeysuckle (flowers) Lonicera periclymenum & caprifolium
Heartsease Viola tricolor
  Many of these can be planted in outdoor 'baby units' and many will be growing in your garden already with any luck. A Wild Flower book will be useful for identification and you will find that most of these are familiar 'weeds'. 

A seed mixture based on this list, 'The Tlady's Mix', is now available from Herbiseed. For details, planting advice and ordering click here.

These illustrations can now be downloaded as a zipfile, to print your own reference booklet. There are ten A4 pages with two species illustrated on each, plus a front and back cover. For best results save to disk, open in your image editing program and print on photo paper at at least 150 dpi. 

To print with  the correct layout, in print Properties click the Layout tab and check 'Reduce/Enlarge' and 'Fit to Page' with A4 selected. (Don't check Centered.)

The sheets can then be halved and assembled in an A5 display book.

All images are copyrighted but may be copied for educational purposes.

 

Small sedums can be very easily propagated to fill seed trays for additional feeding and dandelion and sow thistle seedlings can be grown from the 'clocks' or transplanted from the garden into pots.  

 

Clover and hairy bittercress also grow well in trays and pots and can be harvested every few days. Edible wild plant mixtures are available from some of the organic seed companies. You will discover by trial other garden and rockery plants which they will eat.  

 
The occasional addition of lettuce and cucumber will not hurt if nothing else is available and can provide valuable moisture in dry weather, but these should never form the staple diet owing to their extremely low nutritional value. Fruit such as tomatoes, apple, plums, peaches and melon can be given as a treat but only occasionally as the sweet, wet conditions created by these foods often cause certain gut flora to 'bloom' resulting in gut irritation signaled by rather wet droppings often containing undigested food.  This is both unpleasant and detrimental to your tortoise's health.  
 

Notes on Feeding and Nutrition  

Food picked from outside your garden should be thoroughly washed to remove any chemical residues from spraying and traffic and of course you must avoid any use of toxic chemicals in your garden, e.g. slug killer, ant killer, pesticides, herbicides - none of these is safe.  
 
Try to feed picked food as fresh as possible to retain the vitamin content, preferably morning (after basking) and mid to late afternoon (when they emerge from siesta) though it can be kept quite well in a plastic bag in the fridge for a couple of days. For very small tortoises chop the leaves to a manageable size with scissors just before feeding.  
 
It is important to provide the opportunity for the youngsters to graze naturally on food plants growing in their areas. This way they will develop muscle and keep down their beaks and claws. This of course means planting and nurturing some of the very 'weeds' you have previously tried to eradicate from your garden - you will learn to love them!  
 
Avoid toxic plants such as daffodil, ragwort, spurge, columbine, hellebore - if in doubt check in a library book on toxic plants. In my experience, they will generally avoid them, but you may inadvertently mix them in with other leaves. To be safe though, remove these from tortoise areas, particularly where the youngsters are, but there is no need to rip them out of your garden!  
 
Avoid high-protein plants such as peas, beansprouts, sweetcorn -  being seeds they are very high in protein so in excess they can not only cause over-rapid growth but also seriously affect calcium metabolism, owing to their high phosphorus to calcium ratio, resulting in over large, soft shelled juveniles.
 
Avoid plants with a high oxalic acid content like spinach
Avoid overuse of kale and sorrel with relatively high oxalic acid content.  
Avoid high sugar foods e.g. fruit in excess.  
Avoid high phosphorus foods e.g. banana - also quite addictive.  
Avoid especially all unnatural foods, particularly high protein and high fat foods like meat-based dog and cat foods, which are without doubt highly damaging to the growth and health of tortoises.  
If in doubt about a particular foodstuff, ask yourself: Would the tortoise be likely to find this in the wild?  If the answer is a resounding NO as in the case of dog and cat food, dairy produce, meat, fish, etc, then DON'T FEED IT!  It will only cause long-term health problems and is totally unnecessary.  
Avoid the use of toxic chemicals such as slug pellets and lawn food in tortoise grazing areas and food picking areas.

Calcium & Vitamin D3  

Tortoises, particularly growing babies and egg laying females, naturally have a high calcium requirement. Vitamin D3 is needed to render the ingested calcium available to the body. The tortoise's body has evolved a mechanism to manufacture D3 through exposure to UV light i.e. the abundant Mediterranean sun. This is why we need to ensure D3 is available both through dietary supplements and by provision of Full Spectrum Light (FSL), in the form of strips or Active UV bulbs. This is particularly vital when summer sun is in short supply or the tortoises are indoors in cool weather, if we are to avoid calcium deficiency giving rise to metabolic bone disease (MBD).  
 

With a wide variety of plant species offered, there should be no problem with providing a range of nutrients, but the best shape and healthiest growth is achieved in my experience by lightly dusting the food once daily with a specially formulated vitamin and mineral supplement such as Vionate or Nutrobal, plus extra calcium. I have a sprinkler jar containing finely ground limestone flour with a little Vionate or Nutrobal, ready to add when feeding.

 

NB As D3 is toxic in overdose, reduce the amount and frequency of supplementation when the tortoises have good exposure to summer sun, but keep supplying calcium in the form of pieces of cuttlefish bone which they will sometimes bite at, and sprinkling food with calcium carbonate powder or scraped cuttlefish bone.  

 
NB So called full spectrum light strips provide nowhere near the amount of UV needed, but if you use them as a temporary measure, be aware that transmission of the ultraviolet part of the spectrum is much reduced after 6 months use, even though the strip still lights up. The newer and more effective combined heat and UV lamps last up to two years, and really are a must when for proper shell and bone development.

Water

Whilst it is true that tortoises are very efficient at extracting moisture from their food, drinking helps them to flush waste and toxins from the body and ensures good hydration of the tissues. Wild tortoises certainly drink when they get the chance and babies love to drink and wallow. Provide a shallow drinking dish e.g. a plastic plant pot saucer weighted with gravel. Babies like to bask and wade in this too. (They will probably be inspired to use it as a toilet too, so change the water frequently!)
 

NEXT: Husbandry through the Year

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