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Jackson ratio

From Wikipedia, the free encyclopedia

Researched and devised by Dr. Oliphant Jackson, the Jackson ratio is a method of determining whether a member of the tortoise species Testudo graeca or Testudo hermanni is maintaining its optimum bodyweight, which is necessary for a successful hibernation.[1]

Calculation

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The Jackson ratio is calculated by taking the weight of the tortoise in grams and dividing it by the cube of the length of the tortoise's carapace in centimeters.[1] This is essentially a value of the density of the tortoise in g/cm3. The optimal value for this ratio is 0.21 with a range of 0.18–0.22 being acceptable for hibernation. Values significantly less than this indicate an underweight tortoise and larger values are indicative of overweight tortoises.

The Jackson ratio is expressed as a graph of minimum and optimum weights for a given carapace length. This exhibits the same principle without the maths.

References

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  1. ^ a b "Jackson Ratio for Tortoises". Tortoise Protection Group. Retrieved 2017-02-24.