Tortoises have evolved to thrive in subsistence conditions in hot, dry places where vegetation is often very sparse. They mainly eat in the morning and in the evening. They'll have a little siesta by sleeping during the hot part of the day. In the wild they are not constantly woken up and offered heaps of succulent food! so they have to walk about and search for food plants, where they'll bite off flowers and leaves on their travels. Growth rings on a wild tortoise are even and flush with the curve of the shell and the scutes form a smooth overall dome shape without bumps.

If you overfeed a tortoise, even on the correct diet, the growth will be too rapid and the growth rings will start to become raised and the shell will become peaky (otherwise known as pyramiding). A tortoise on an incorrect diet such as dog and cat food, cheese, bread, and many other unnatural items will result in your tortoise becoming a very sorry animal. Soft shelled, deformed, weak and potentially fatal kidney and liver problems are a few of the health issues your tortoise can experience if fed incorrectly. Metabolic bone disease (MBD) is a common cause of captive reptile fatalities and is caused by insufficient Calcium being laid down in the bones.

A tortoise diet should be vegetarian, adequate in moisture, high-fibre, vitamin and mineral rich, low-fat and low-protein. Even high protein vegetables should be avoided (e.g. peas, sweet corn, bean sprouts) to achieve a gradual and even shell growth.

The growth of young tortoises should be monitored closely as you need to ensure that they aren't growing too quickly. We keep a fortnightly record of all our tortoises weights, lengths, and ratio's as well as a diary where we keep note of general observations (i.e. health changes, behaviours, etc). Keeping records can highlight possible changes in your tortoises health pattern. It can also allow you to take prompt action before it's too late.

See the Jackson Ratio Calculation below which explains how to measure your tortoise and calculate their weight to length ratio. Also, to make things easier, we have included a Jackson Ratio Calculator that will work out your tortoises ratio for you.

 

	Calculating the Jackson Ratio:         Measure the weight (in grams)         Measure the Straight Line length (in cm)         Calculate weight divided by length (in cm)         (Weight ÷ length x length x length)         (e.g.  70g ÷ 7cm x 7cm x 7cm)
The carapace length of a tortoise is measured as a straight line (SCL).

After measuring your tortoise, you can check your results against the 'Jackson Ratio Charts'. The Jackson's Ratio chart is used to determine the ratio between the 'SCL' length of your tortoise (the straight carapace length) and the weight of the tortoise to determine its health status prior to hibernating or to assist in obtaining an average growth rate. To assist you, we have graphs for both hatchlings and  juveniles / adults. To navigate to these graphs, please click on the link below.

Link to 'Jackson Ratio Charts'