Snakes have extremely slow metabolisms, even for reptiles, so as a result, their food intake needs are very modest. Many species of snakes are opportunists that will eat virtually every time food is offered, because their instincts tell them that the next meal may not arrive for months.
As a result, snakes can be prone to obesity. Obesity in reptiles is extremely dangerous, and it leads to a problem called 'fatty liver disease'. Essentially, the liver becomes riddled with fat cells, until it can no longer properly function, and the animal dies.
So, how much food is too much?
Most species of snakes should be fed just once per week, and should receive a food item that is as big around as the widest part of their body. Some slender-bodied species may need a few similar-sized food item. (Adult corn snakes may eat 2 or 3 adult mice, for example, while an adult ball python may eat just one medium-sized rat).
Some high metabolism species such as garter snakes need to eat about twice a week. A few VERY low-metabolism species, such as some boas, need to eat only once every 10 to 14 days.
How do you tell if a snake is too fat? The signs aren't necessarily the same as they are in other animals. Some snakes naturally LOOK fat, when they are at a normal weight.
Obese snakes will have the following signs:
You will be able to see skin between their scales, when they are at rest (not coiled up tightly, as that can show skin on the outside of the curve, normally).
You may see a 'bump' where the tail begins--the area above the tail may not flow smoothly down the tail, but may be larger around than the tail is at its base. The tail is everything behind the cloaca.
If you see these signs in a snake, reduce its food intake dramatically--cut the size of the prey down (if you were feeding medium, feed small, for example), and reduce the feeding frequency by at least half. Weigh your snake regularly. If the weight doesn't go down, reduce the frequency of feeding even more, until you begin to see weight loss.
Once your snake has returned to a normal weight for its size and species, place it on a feeding schedule to maintain that weight, without allowing it to gain weight again.
Baby Snakes:
Many baby snakes can't really become obese--most pythons, for example, will simply put all that you feed them into growing bigger, instead of fatter. Some baby snakes, however, will develop severe health issues if they are overfed.
Following feeding guidelines for these species carefully. (One example is the boa constrictor. Overfed boa hatchlings will grow into adults with tiny heads and very short lifespans).
