Melissa Kaplan's
Herp Care Collection
Last updated January 1, 2014

Lethargy in Reptiles

©2000 Melissa Kaplan


The Online Medical Dictionary describes lethargy as "Abnormal drowsiness or stupor, a condition of indifference." Lethargy is a very different condition than the quiet-but-alert behavior generally called "stationary alert" by ethologists.

A reptile who has recently eaten, or is entering the pre-shed stage, or got up on the wrong side of the cage, or is sleepy, will still be alert to his surroundings, responsive to stimuli such as loud noises, touch, and pain. A lethargic reptile will not.

While in stationary alert mode, if the eyes were closed during rest, they will open when there has been noise stimulus and some movement at touch, such as the normal moving into your hand when petting him or picking him up to hold him. A lethargic reptile may not open his eyes or may open one eye and close it again (assuming the species has moveable eyelids), and will not be terribly responsive to touch if at all.

Pinch a stationary alert reptile's toe or fold of skin between your thumbnail and middle finger, and you will see just how alert he is; do the same to a lethargic reptile and at most you might get a pulling away of the limb (or body, if a snake).

In a lethargic reptile, visible movement related to normal respiration may be absent because the reptile is breathing so slowly and shallowly; an EKG may be required to determine if there is any heartbeat at all. If a sick reptile has a respiratory infection or other difficult breathing (as may happen after the ingestion of a toxic substance), the bellows-like movement of the rib cage may be more apparent than usual. With toxic ingestion, there may be increased salivation.

The muscle tone - the normal resistance you feel when you lift up, hold and manipulate a healthy, alert reptile - will be greatly reduced or absent in lethargic reptiles. The body and limbs will either feel weaker or flaccid, with little resistance to forced movements.

A lethargic reptile may lay in unusual positions, being too weak to adjust its limbs to a more normal, comfortable position for the species. When a lethargic reptile's limb or tail is moved, it may stay where you place it, or it may flop down if let go after lifting it. A health reptile, on the other hand, will readjust itself to a comfortable position, and may control the descent of a dropped limb or tail. A healthy reptile will turn an eye towards to as it tries to figure out what you are doing; a lethargic reptile likely will not open its eyes at all, or move its head if it has no moveable eyelids.

Another way to describe it: stationary alert is normal for reptiles; lethargy scares the bejeezus out of you.



stupor: The partial or nearly complete unconsciousness; the reptile responds only to vigorous or very painful stimulation

ethology: Ethology is the branch of zoology that studies the behavior of animals in their natural habitats

Related Articles

Signs of Illness & Stress

Signs of Ingestion of Toxic Substances

Observations on disease-associated preferred body temperatures in reptiles

Need to update a veterinary or herp society/rescue listing?

Can't find a vet on my site? Check out these other sites.

Amphibians Conservation Health Lizards Resources
Behavior Crocodilians Herpetology Parent/Teacher Snakes
Captivity Education Humor Pet Trade Societies/Rescues
Chelonians Food/Feeding Invertebrates Plants Using Internet
Clean/Disinfect Green Iguanas & Cyclura Kids Prey Veterinarians
Home About Melissa Kaplan CND Lyme Disease Zoonoses
Help Support This Site   Emergency Preparedness

Brought to you thanks to the good folks at Veterinary Information Network, Inc.

© 1994-2014 Melissa Kaplan or as otherwise noted by other authors of articles on this site