Assessing the Sick Snake

Normal behavior

Snake behavior will vary with the species, however the normal snake tends to be alert, responsive, and curious. Frequent tongue flicking is a sensory gathering behavior used to deliver scents to the vomeronasal organ. The normal snake is generally active, often coiling or twining its body. This is particularly true for smaller species. Signs of aggression in the snake may include a rigidly coiled body with the head held up and away from the perceived threat (Fig 1). The mouth may be open.


Signs of illness

Exotic animal medicine requires a delicate balance between medical concepts true for all living creatures (“one medicine”) and species-specific information and this is true for snakes (Table 1).


Figure 1. A rigid, coiled posture may indicate aggression or tension in the snake. Image provided by Dr. Ed Ramsay. Click image to enlarge.

Table 1. Signs of illness in the snake
“One medicine” concepts Unique to snakes
  • Depression, listlessness, inactivity
  • Anorexia (The significance of this finding can vary with snake size, age, season, and reproductive status. Snakes will also go off feed before shedding).
  • Weight loss:  reduced epaxial musculature
  • Wrinkled, inelastic skin (Fig 2) and sunken eyes may be observed with dehydration and emaciation.
  • Open-mouth breathing or dyspnea observed with advanced lower respiratory tract disease.
  • The weak or lethargic snake may lie listlessly in an uncoiled or “stretched out” position. There may be loss of tongue flicking or lack of interest in the environment
  • Evidence of retained shed or dysecdysis (Fig 3) including retained spectacle(s) may be seen with ill thrift or husbandry problems.
  • Severe weakness or neurologic deficits may manifest as a loss of the righting reflex.
Dysecdysis or retained shed in a ball

Figure 2. Dysecdysis or retained shed in a ball python (Python regius). Image by M. Scott Echols.

Dehydrated boa skin

Figure 3. Dehydrated, wrinkled skin in a red-tailed boa (B. c. constrictor). Image by M. Scott Echols.


Physical examination

    • Perform a careful oral examination including the teeth, gingiva, palate, palatine vessels, glottis, and tongue.
      • Use an oral speculum such as a rubber spatula or tongue depressor.
      • Mucous membranes are generally paler in reptiles when compared to mammals. Mucous membrane color is often pale pink to white.
      • Evaluate the glottis for red, mucoid discharge, and/or swelling.
      • Look at the back of the throat for evidence of discharge or mass lesions.
    • Evaluate the eyes and the clear scale or spectacle overlying the cornea. The spectacle will normally appear cloudy prior to shedding (ecdysis). Cloudiness may also be observed with a difficult shed or dysecdysis.
    • Examine the nares for evidence of nasal discharge.
    • Palpate the epaxial muscle mass and along the ribs to assess body condition and to feel for lumps and bumps (Fig 4). An obese snake will have a rounded contour as well as taut skin and intracoelomic fat bodies.
Palpating epaxial muscles

Figure 4. Palpate the epaxial muscles and along the ribs. Click image to enlarge.

  • Palpate the coelom for evidence of fluid or mass lesions.
  • Evaluate the skin from snout to tail tip for evidence of a difficult shed or dysecdysis, lumps or bumps, and ectoparasites like mites. Snake mites may be black, brown, tan, or red. Mites are most commonly found within the gular fold, around the eyes and around the vent. Carefully evaluate the belly scales for skin lesions or erythema. A blush may be observed just before the  snake goes “in blue” prior to shedding or with sepsis.
  • Evaluate the vent for evidence of fecal pasting, erythema, or prolapse.

Gender is most commonly determined by cloacal probing. Although probing is a simple technique it is best learned by observation and training and the procedure will not be described here.