While we focus on the length of the tortoise, we often ignore the pet’s weight. But remember, a fluctuating weight is often a reminder that the tortoise is sick. To pick up this hint, you first need to understand how much a tortoise should weigh.
A tortoise’s weight can vary from 150 grams to 200 pounds, depending on the species and age. The Donoghue ratio helps to determine the targeted healthy weight of the tortoise against its size. Likewise, the Jackson ratio and BMI let you determine whether the tortoise is underweight or overweight.
I have discussed both tortoise weights in detail below. Also, I have added the tricks that will help your pet combat unhealthy weight and get back in shape.
How Much Does A Tortoise Weigh?
The weight of a tortoise depends on the species. Though you can not calculate the exact healthy weight of the species, you can make an educated guess. Here is a weight chart of adult tortoise species,
|Tortoise Species||Weight Of Adult Tortoises|
|Sulcata Tortoise||150 – 200 pounds|
|Aldabra Tortoise||350 – 550 pounds|
|Spider Tortoise||Up to 400 grams|
|Egyptian Tortoise||Up to 400 grams|
|Russian Tortoise||3 – 3.5 pounds|
|Greek Tortoise||2 – 3 pounds|
|Elongated Tortoise||Up to 7 pounds|
|Marginated Tortoise||Up to 11 pounds|
|Indian Star Tortoise||4.9 – 5.5 pounds|
|Radiated tortoise||Up to 35 pounds|
|Pancake Tortoise||1 pound|
|Leopard Tortoise||Up to 61 pounds|
|Burmese Mountain Tortoise||70 – 100 pounds|
|Red Footed Tortoise||Up to 25 pounds|
|Yellow Footed Tortoise||Up to 25 pounds|
N.B. The above chart includes the expected weight of adult tortoises. The weight can be more or less depending on the size and health of the pets.
What Is The Healthy Weight Structure For Tortoises?
Have you ever heard of the BMI index? It indicates whether you are overweight, underweight, or healthy. Luckily, scientists have developed similar methods to measure a tortoise’s health too.
3 popular methods to determine the healthy weight of tortoises are,
1. Jackson Ratio
The Jackson ratio is the calculative relationship between the tortoise’s weight and body length. We follow the below steps to calculate the Jackson ratio of a tortoise,
- Measure the carapace length of the tortoise in cm3.
- Weigh the tortoise in grams.
- Divide the weight by the length, which will give you the density of the tortoise in grams/cm3.
- Compare the tortoise density to the standard Jacksion ratio chart to determine the pet’s health.
The healthy weight and Jackson ratio relationship chart is mentioned below,
|Jackson Ratio||Health Indication|
|0.16 or under||Underweight|
|0.17 – 0.18||Underweight to hibernate|
|0.19 – 0.20||Normal weight|
|0.21 – 0.22||Healthy weight|
|0.23 or above||Heavy, overweight, or carrying eggs|
I know the Jackson ratio is quite popular to determine whether the pet tortoise is in the healthy weight range. The method is also highly recommended by vets and experts. But the biggest limitation of this technique is that it does not apply to all tortoises.
The Jackson ratio is highly effective for average-bodied tortoises, especially Mediterranean tortoises. Hence, you can use the Jackson ratio with Hermann’s tortoise and Spurred Thigh tortoise. But the method is invalid for the Horsefield tortoise and the marginated tortoise.
Well, the Jackson ratio fails on Horsefield tortoise and marginated tortoise due to their physical characteristics. For example, the marginated tortoises have a narrow and tall carapace, while the Horsefield tortoises are short and boxy. Therefore, your tortoise may fall in the underweight category even when it is healthy.
Jackson ratio method also does not work on the following tortoise species,
- Sulcata tortoise
- Leopard tortoise
- Hinge back tortoise
- Tropical or non-hibernating tortoises
Thus, this Jackson ratio is only used for the Spurred thigh tortoise and Hermann’s tortoise. The method is primarily used to determine the hibernating ability of the creatures. Ratios below 0.19 and above 0.23 are totally unfit for hibernation.
2. Donoghue Ratio
Luckily, the Donoghue ratio has overcome the Jackson ratio species limitations. Susan Donoghue developed this method after going through 76 tortoises and 11 box turtles, representing 11 species.
Unlike the Jackson ratio, the Donoghue ratio applies to almost all tortoise species. However, the Donoghue ratio has some limitations too. For example, this technique works flawlessly with young tortoises but fails with hatchlings.
With the Donoghue ratio, we multiply the carapace length of the tortoise with a magic ratio. The result gives us an idea of how much the tortoise should weigh. In simple terms, the rule of thumb for determining the weight is,
1. Target Weight in grams (tWTgr) = Straight Line Carapace Length (SCL) in cm3 x 0.191
2. Target Weight in ounces (tWToz) = Straight Line Carapace Length (SCL) in inches3 x 0.113
3. BMI Index In Tortoises
We can use the Donoghue ratio to measure the tortoise’s BMI and determine its health status. The ideal formula to calculate the BMI index of a tortoise is,
cWT (current weight)/ tWT (Targeted weight) = Tortoise BMI
Tortoise BMI Chart:
|BMI Ratio||Weight & Health Status|
|0.66 or lower||Extremely underweight|
|0.66 – 0.83||Dehydrated or underfed|
|0.83 – 0.99||Little underweight|
|1.01 – 1.16||Little overweight|
|1.16 – 1.33||Overweight|
|1.33 or over||Extremely overweight|
Example: Follow the below steps if you want to determine the BMI of the tortoise,
- Measure the carapace length of the tortoise first. Say, your pet has a straight-line carapace of 12 centimeters.
- Use the Donoghue ratio to measure the targeted healthy weight of the tortoise. Therefore, the tWTgr = 12 x 0.191 = 2.292 grams.
- Weigh the tortoise in the digital machine. Say, your tortoise weighs 2.1 grams.
- Now divide the current weight by the targeted weight to determine the BMI of tortoises. Hence, the BMI of your pet = 2.1/ 2.292 = 0.91.
- According to the BMI chart, your pet tortoise is a little underweight.
What Is The Right Way Of Measuring Tortoise Length And Weight?
No matter if you go for the Jackson ratio or the Donoghue method, you need to measure the tortoise accurately. Otherwise, you will fail to calculate the precise length and weight of the tortoise.
Here is a brief instruction on measuring the tortoise,
1. Straight Line Carapace Length:
- Set a paper on the floor against a solid wall.
- Place the tortoise on the paper, ensuring its head faces the wall.
- Gently force the tortoise to withdraw its limbs into the shell.
- When the tortoise is retracted completely, ensure its front shell touches the wall.
- Use a pencil to mark the base of the tortoise on the paper.
- Remove the pet and use a ruler to measure the distance between the front and base.
- Give the tortoise a proper bath and dry it afterward.
- Put the pet directly on the digital scale to measure the weight.
Why Do You Need To Monitor The Tortoise’s Weight?
The tortoise’s weight indicates so many things about the pet, including the adjustment it requires in lifestyle. Such as,
- A tortoise with underweight is definitely unhealthy. It should be well-fed, maintaining a strict diet routine. I have made a feeding chart for pet tortoises that you can access from here. An underweight tortoise has low immunity and is more prone to diseases.
- Being overweight is also a curse for tortoises. It increases the risk of liver or kidney damage, and the pets find trouble walking. Food is not the only issue responsible for being overweight. But congested spaces and lack of physical exercise also lead to obesity.
- When hibernating, you must check the weight of the tortoise. An underweight or overweight pet is not ready for the stressful hibernation process. You need to work on the tortoise’s weight by feeding it right and adjusting its lifestyle before the hibernating season.
Why Is My Tortoise Overweight?
Honestly, obesity in tortoises comes with other physical problems. For example, an overweight tortoise can not walk properly.
Sometimes the fats on the neck and the limbs prevent these pets from retracting in their shell completely. Also, you can not ignore the risk of liver or kidney damage and heart disease associated with obesity.
Basically, 2 factors cause obesity in tortoises,
Tortoises are opportunistic creatures. So, they keep eating as long as the food is available. Therefore, if you offer meals more frequently and in bulk, the tortoises may end up being overweight.
2. Lack Of Exercise
Tortoises also require physical movements to shed the extra fat like humans. If you put these pets in a congested space, they cannot walk or graze. As a result, the tortoises gain weight.
Why Is My Tortoise Underweight?
Being underweight in a tortoise is definitely a matter of concern. A skinny tortoise indicates that you have lackings in the care sheet. I can point out 4 major factors that lead to weight loss in tortoises,
Apparently, dehydration causes massive weight loss in tortoises, especially in hatchlings. The absence of a water source, irregular soaking routine, and low moisture level lead to dehydration and weight loss in tortoises.
Your tortoise will definitely shed weight if you offer them less food or a boring meal. The lack of nutrition will take a toll on their weight, making them vulnerable to diseases.
Sometimes you make the pets full of lettuce or cucumbers, which have more water content and fewer minerals. As a result, the tortoises stay weak and underweight even after having a full stomach.
3. Refuse Food
There are situations where the tortoises avoid meals altogether. For example, boring, repetitive meals, low temperature, stress, etc. The tortoise with less interest in foods will lose pounds.
The most common symptom of any tortoise illness is weight loss. During sickness, the tortoises avoid eating and invest their stored energy in healing. Hence, you notice them shedding weight.
Tortoise weight loss is more prominent when they are under parasitic attack. The worms live off the pet’s body and suck up all the nutrition. Therefore, the tortoise gets skinny, has sunken eyes, and suffers from diarrhea.
As mentioned, tortoises may refuse to eat when stressed. As a result, you notice them losing weight. Factors that can stress a tortoise are a congested space, multiple tankmates, illnesses, loud noise, improper temperature, low humidity, etc.
How To Maintain The Healthy Weight Of My Tortoise?
Maintaining a healthy weight is mandatory for tortoises. Let me remind you that tortoises have no ideal range of healthy weight. Instead, the scale will change depending on the species.
You can measure your tortoise’s healthy weight by adopting the Jackson or Donoghue ratio.
Now, if your tortoise is underweight or overweight, you need to adjust to a healthy weight. Otherwise, the pet will suffer from unwanted diseases and may have a shorter lifespan.
You can maintain the healthy weight of the tortoise by the following steps,
1. Draft A Balanced Diet Chart: Tortoises prefer a high fiber and low protein diet. An excessive amount of protein leads to fat accumulation on the necks and limbs of the pets. Hence, plan the meals considering the tortoise’s needs and the nutritious food value.
2. Decide The Quantity: You should not overfeed or underfeed the tortoise. The ideal quantity for feeding the pet is 5% of its weight. Some owners suggest feeding the amount that fits in the tortoise’s shell.
3. Maintain A Strict Routine: The baby tortoises must be fed daily as they require nutrition to grow up. On the other hand, young and adult tortoises can adjust well to a 5-day-a-week feeding routine. The senior tortoises may feel more comfortable with a 3-day-a-week food schedule as they have less appetite.
4. Encourage The Tortoise To Work Out: You need to take the tortoise to the open green fields and let them graze. This not only refreshes the pets but also acts as an exercise. You can also trick the tortoise into shedding pounds by placing the meals in a hard-to-reach position.
5. Take Care Of The Environment: Drop or rise in temperature, improper humidity, congested pen, and filthy habitat are enough to stress out a tortoise. Taking care of each factor will relax the tortoise and boost its appetite. Hence, the pet will stay in the ideal shape.
6. Bring Food Variety: Hibernation is not the only reason tortoises refuse food. But if you repeat the same meals daily, the tortoises will lose interest in the food and suffer from being underweight. So, experiment with the taste of the pets and bring variety to the meals to excite the tortoises into eating.
7. Medical Care: You will notice weight fluctuation in the sick tortoises. Look for other symptoms to diagnose the disease and adopt the necessary treatments. Of course, consulting the vet is mandatory before offering the tortoise any medicine.
Before You Go
Do you know your responsibility if the tortoise gets fat? I have discussed how you can handle tortoise obesity at home in the article mentioned below.
Is Your Tortoise Getting Fat? Here Is What To Do
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