Body Condition Score for Reptiles

By PetMD Editorial on Feb. 27, 2017

By Laurie Hess, DVM, Diplomate ABVP (Avian Practice)

The term “body condition score” is a standard scale used by veterinarians to subjectively rate the body weight of an animal relative to what is considered “normal” for a particular species; it is most commonly used to describe dogs and cats. This scale typically ranges from 1-9, with 1 connoting emaciation, 5 suggesting normal weight, and 9 indicating obesity.

This same scale may be used to describe body condition in other species as well, yet little has been published defining the exact criteria for body scoring animals other than dogs and cats. This is especially true for reptiles, of which there are so many different types.

The Nutritional Importance of Temperature and Light for Reptiles

Unfortunately, many reptile owners never see reptiles other than their own and therefore have no idea that their pet is grossly overweight or severely thin. This is particularly an issue for reptiles, as these animals typically have specific requirements for diet, temperature, light, and humidity, so many reptile owners are not only feeding their pets incorrectly, but also aren’t maintaining their pets’ environments properly.

Reptiles are homeotherms; their body temperatures are determined by their external environment temperatures. Every reptile has a specific temperature range (their preferred optimum temperature zone, or POTZ) at which their metabolism, immune system, and digestive tract functions best, and when they are not kept within this temperature range, they may not digest food properly and may not have an optimal body condition, even when they are fed properly otherwise. In addition, many reptile owners are not educated about what their pets should be eating, or may choose to feed only what their animal likes best—a scenario that commonly leads to malnutrition and either obesity or emaciation, depending on what is fed.

Some reptiles are herbivores (vegetable-eaters), some are carnivores (meat-eaters), and some are omnivores (eating both animal and vegetable matter). Reptile owners should be sure they know what foods their pets need to stay nutritionally balanced.

In addition to an appropriate diet, many reptiles also require ultraviolet (UV) light to activate vitamin D in their skin, which enables them to absorb calcium from their food. Without UV light, even reptiles that are fed appropriate diets may look thin and stunted from lack of calcium absorption. It is therefore critical for reptile owners to know not only what to feed their pets, but also how to set up their environments properly to ensure these animals are getting the UV light and warmth they need to metabolize and digest their food properly.

To help educate reptile owners about proper body weights for their pets, here are some general guidelines, based on reptile classification, for determining whether your reptile is at its proper body condition.


There are many different species of lizards, and they all have different body shapes. In general, a lizard is considered too thin when its leg bones, pelvis, hips, skull, ribs, and spine (visible down the length of its back) are prominent through the skin from muscle loss. Many lizards—especially leopard geckos—will lose fat that is normally stored in the uppermost part of their tails. This loss of tail fat is a condition commonly called “stick tail.”

Healthy lizards typically have enough fat in their tails to be nearly the width of the rest of their bodies. Very thin lizards also may lose the fat stored from behind their eyes, causing their eyeballs to sink further back into their eye sockets.

Overweight lizards, on the other hand, may have a thick layer of fat over their backs and sides, making it impossible to feel their spines and ribs underneath. In addition, many fat lizards will have fat deposits under their necks, making them look like they have jowls, and may have torsos that appear pear-shaped rather than streamlined. Obese lizards also may have so much fat deposited in their tails that their tails are wider than their bodies.

*Example: Leopard gecko with different body condition scores


Turtles and Tortoises

Given that these animals live inside a bony shell, it is often difficult to assess whether they are the proper weight. Very thin turtles and tortoises will feel light when picked up due to a lack of not only body fat and muscle mass in their limbs and neck, but also of minerals (such as calcium and phosphorus) deposited in their shells. Like the eyes of emaciated lizards, the eyes of thin turtles and tortoises may look sunken due to lack of fat behind their eyes. Thin turtles and tortoises also may have a sunken appearance to their armpits and groin (inner legs) from lack of fat deposited there. In addition, they often have loose flaps of skin in these areas, as well as around their necks, just as obese people do when they lose large amounts of subcutaneous fat.

Overweight turtles and tortoises, on the other hand, may have large amounts of fat deposited behind their eyes, making them look “bug-eyed.” They also may have large fat deposits (appearing as rolls or folds) in their armpits and groin, and around their knees and necks, so that they can’t fully retract their limbs or heads back into their shells. Obese box turtles may have such large fat pockets in their bodies that they may not be able to fully close their shells.


Like thin lizards, thin snakes will have prominent ribs and spinal vertebrae along the length of their backs, as well as prominent skulls. These bones will be visibly conspicuous not only through the skin but also palpably when the snake is touched due to lack of muscle and fat deposits. Thin snakes also will feel light when held and their eyes may look sunken.

Obese snakes, in contrast, will have so much fat deposited along the length of their spines that vertebrae will not be felt when their backs are palpated. Unless a snake has just eaten, the thin skin between the scales should not be visible.  Fat snakes may have lumps of fat deposited under their skin in several areas, making the skin between their scales stand out and making their bodies appear uneven and less tubular. Overweight snakes often have a wider dorsal (seen from the top) appearance than they do lateral (seen from the side). Overweight snakes also may have folds of fat that are visible when they move and bend into an S-shape.

What You Need to Know Before You Get a Reptile Pet

Reptiles have very specific nutritional and environmental requirements that need to be met for them to thrive. Prospective owners must educate themselves before getting one of these animals by seeking the advice of a veterinary professional who is well versed in herpetology (reptile and amphibian care), or a knowledgeable reptile breeder, to ensure that they will be able to provide all that is required for optimal health. Professional advice should continue to be sought after to be sure that they are doing everything right for their pets and that their pets’ health needs are being met.

Reptile owners can visit pet stores, reptile breeding facilities, zoos, and local reptile shows to become familiar with what a “normal-weight” looks like for their reptile’s specific species. Like other animals, reptiles must exercise to prevent obesity and to promote normal muscle development, and they need regular veterinary checkups.

If a reptile owner has any doubts that his or her pet is not at an appropriate weight or is in ill health, either when they first get the pet or at any time thereafter, the animal should be checked out by a qualified veterinarian to make sure the pet is on a healthy track.

*Adapted from “Reptile ID: Expert tips on species, gender, and body condition score,” by Stephen Barten, DVM

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