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.

The length of the carapace is measured in millimeteres, and compared to the weight of the tortoise in grams. Plotting the two values will show if the tortoise has a weight/length ratio optimal for hibernation.

External links

• http://www.slowcoach.org.uk/care/jackson/jackson.html
• http://www.heosemys.org/Jackson.php