Chapter 8 Snakes
Snakes are popular reptile pets, and there has been a resurgence in their popularity with the breeding of a variety of colour morphs. A huge number of species are available in the pet-trade, but the commonly kept species are listed in Table 8.1.
|The royal python (Python regius)||This is a small python, growing to 90–120 cm. It has a not undeserved reputation for prolonged fasting, probably as a result of poor husbandry and endogenous cycles, although this is less pronounced with the modern captive-bred individuals and colour morphs||Dermatitis, dysecdysis and pneumonia. Anorexia, especially in wild caught or captive farmed individuals|
|The Burmese python (Python morulus bivittatus)||This python is a potentially very large snake; adults can reach up to 5–7 m long with a large muscular cross-section. Adults are usually reasonably behaved but hatchlings and youngsters can be aggressive||Dysecdysis, burns, pneumonia, inclusion body disease (IBD)|
|Boa constrictor (Constrictor constrictor)||A large snake up to 1.8–3.0 m long. Usually handleable but some individuals can be aggressive. Several colour morphs available and there is some selective breeding to reduce size using naturally occurring dwarf island subspecies||Snake mites, dysecdysis, inclusion body disease (IBD)|
|Corn snake (Elaphe guttata guttata)||Moderate-sized rodent-eating snakes that make excellent introductions to snake-keeping. This is probably the nearest there is to a domestic snake; it is available in a very wide range of colour morphs, grows to a manageable size (around 1.0 m) and readily takes frozen-defrosted prey||Dysecdysis, cryptosporidium|
|King snakes (Lampropeltis spp)||King snakes are natural predators of snakes and other reptiles and so are usually kept individually||Dysecdysis, obesity|
|Garter snakes (Thamnophis spp)||Small to medium-sized snakes. Can be nervous on handling. Many of these are earthworm, fish and amphibian predators, although they can be readily converted on to mammalian prey||Septicaemia, thiamine deficiency|
The internal anatomy of a snake is shown in Figure 8.1 (see also ‘Radiography’, in Musculoskeletal Disorders).
Consultation and handling
A healthy snake should be reasonably alert and responsive to touch. If it is flaccid or exhibiting CNS signs, such as ‘star-gazing’ it is likely to be suffering a septicaemia, poisoning or possibly a protozoal infection such as acanthamoeba.
Start the examination at the head and work backwards. Larger snakes such as the pythons and boas may require one or more people to hold them while you perform your examination. A gag is usually required to open the mouth – wooden spatulas work reasonably well and are less traumatic than metal equivalents. Do not encourage staff or clients to drape large constricting snakes across the shoulders and around the neck because if the snake feels insecure, it may well tighten its grip unexpectedly.
Venomous snakes require specialist handling equipment and should only be handled by a competent herpetologist or while under an anaesthetic.
Many snakes are not obviously sexually dimorphic or dichromatic. The safest and most popular way of sexing monomorphic snakes is by ‘probe-sexing’, where a small, well-lubricated and blunt-ended rod is gently inserted into the cloaca and then directed caudally to one side of the midline so as to slot into the inverted hemipenes of the male, if present. If female, the probe will only travel a few subcaudal scales, while in a male it will pass a significant distance (Fig. 8.2).
Provide an appropriate environment, including provision of:
See ‘Fluid Therapy’, in Lizards.
Dehydrated snakes typically show an increase in skin tenting and folding, especially longitudinal folding. Daily bathing in shallow, warm water is often beneficial; it encourages many snakes to drink as well as defaecate and urinate.
Fluids administration in snakes
Liquidized normal diet or proprietary support diets can be used, given either by stomach tube or by oesophagostomy tube. Force-feeding of prey species may prove traumatic in inexperienced hands.
Normal ecdysis in snakes
Shedding in snakes is a cyclical event with synchronous replacement of the whole epidermis at the same time. Snakes should shed their skin in one continuous sheet, starting rostrally, and any deviation from this should be considered abnormal. Ecdysis is under both environmental and endocrinologic control. Ecdysis in snakes follows the following sequence:
Differential diagnoses of skin disorders
See also Skin Disorders, in Lizards
Shedding difficulties (Dysecdysis)
Erosions and ulceration
Nodules and non-healing wounds
Changes in pigmentation
Findings on clinical examination
Respiratory tract disorders
Findings on clinical examination
Gastrointestinal tract disorders
Disorders of the oral cavity
Note that mucus may be seen in the mouth as part of respiratory disease and should be differentiated.