Don't cast me aside... Shedding in snakes.
Updated: Aug 8, 2021
A snake’s shed is the act of removing the dead top layer of skin and scales.
Head, tail and mid body shed skin of an Inland Taipan, Oxyuranus microlepidotus.
The top layer of snake skin is known as the epidermis. Just like in people, this consists mostly of keratin and is structured in layers. The outermost layer is shed off to allow the snake to grow. This includes the brille or spectacle (more commonly referred to as the eye cap or scale).
Before a snake will shed the top layer of skin, the layer below has begun to harden, allowing the snake to become more resilient to injury. This is characterised by a noticeable difference in the snake’s colouration. The top layer becomes a lot duller than normal. A milky blue fluid is formed and begins to separate the two outermost layers of skin from each other. This is referred to as ‘in blue’ or ‘opaque’. Right before the snake is ready to slough, the blue fluid is re-absorbed. The lack of lustre in the scales will remain until the snake shed the outer layer of skin.
Common Tiger Snake, Notechis scutatus scutatus 'ïn blue' and with no lustre to the scales. This snake was a few days off shedding.
The regularity of shedding is linked to the growth rate of the snake, rather than the age of the snake. Young snakes usually grow faster than adult snakes, so they tend to shed more frequently. The skin being shed will stretch as it is being discarded. Sometimes it can stretch as much as 30% of the actual body size.
Handling a snake prior to, or during the shedding process should only be done if absolutely necessary (aiding the snake in removing a difficult slough) as it can damage formation of the underlying skin. This may lead to further complications such as retained shed, bruising to the new layer of skin, or a retained brille.
Just prior to sloughing, it is advisable to slightly increase the humidity within the enclosure and if not already in the enclosure, add a rough object like a large, clean rock that cannot be moved to aid the snake with the sloughing. During this time ensure that the snake has enough water to drink and also to adequately soak in. If the snake dehydrates, it can cause problems throughout the sloughing process. Problems during the sloughing process may result in a bad shed. During this time, snakes tend to be more nervous, some even agitated. If your snake is normally calm, this uncharacteristic attitude is a result of decreased visual acuity Due to stress they may also cease feeding at this time.
To begin the sloughing process the snake usually starts rubbing its nose and chin on cage furnishings, walls and doors to aid in loosening the skin. Starting at the rostral and mental scales, the skin will turn inside out as it is cast off. It is quite interesting to watch.
This is the same Common Tiger Snake, Notechis scutatus scutatus a day after sloughing. Notice the lustre brought back to the scales.
Once a snake has sloughed, the skin or cast should be examined to ensure that both of the brilles or eye spectacles have been removed. It is also advisable to check the snake, especially on the tail tip and the cloaca to ensure the whole skin has come away and there are no old pieces of skin left on the new. Leaving remnants of the older skin on the new can lead to problems sloughing next time, tail tips lost and disease.
Other information such as scale counts, identification , and even DNA collection can be carried out on the shed skin. This is far less invasive and more ethical from an animal welfare perspective than conducting on a live snake.
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Image: Pseudoferania polylepis, Macleay's Water Snake.
References and recommended reading:
Eipper S.C. 2012 A Guide to Australian Snakes in Captivity - Elapids & Colubrids, Reptile Keeper Publications, Burleigh Heads
Eipper S.C. & Eipper T. 2019 A Naturalist's Guide to the Snakes of Australia, John Beaufoy Publishing, Oxford