Maxwell Knight and snake skins – a new approach to an old challenge

 

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A Letter to The Editor The Herpetological Bulletin
18th June 2017

Dear Sir

I was interested to read the Short Note “Lamination as a method of preserving sloughs” by Steven JR Allain and Mark J Goodman (The Herpetological Bulletin (2016) 138, 29-30). The technique they describe would appear to be an excellent approach to the long-term retention and examination of shed skins.

There are two additional purposes to which such preserved sloughs might usefully be applied. The first of these is when the slough is “evidence” in a legal case – for instance, where there is a suggestion that a captive snake was treated cruelly or a free-living snake was taken illegally from the wild. The former might warrant gross and microscopical examination of the slough for evidence of injuries, including scars from burns and sites of tick attachment, and the latter differentiation, using scalation, of (say) an adder, Vipera berus, from a smooth snake, Coronella austriaca.

The second important use of shed skins is to diagnose disease. A freshly sloughed skin may show lesions due to physical or infectious insults (see above) and, if sampled, can yield pathogenic organisms such as mites, bacteria and fungi. Allain and Goodman mention that a piece of slough (“part of the discarded or excess trim”) can be retained for DNA studies. Such small samples might also be set aside for other investigations – for example, for chemical analysis, as described by Jones et al (2005) in the context of polychlorinated biphenyls.

Methods of examination of snake (and other) sloughs for forensic and veterinary purposes have been detailed in a number of texts, including a standard work about wildlife forensic investigation (Cooper and Cooper, 2013). The value of sloughs collected in the wild was described, in the context of non-invasive health monitoring of wildlife, including reptiles, by Cooper (1998).

In passing, I should mention that I first developed my keen interest in the sloughs of reptiles when I was a teenager, 60 years ago. I was already a keen field naturalist and I kept reptiles in captivity. My mentor, the famous naturalist Major Maxwell Knight (Knight, 1959), taught me to collect and save shed skins so that, in addition to being available for educational purposes, they could be used a) to identify a reptile, b) to sex it, and/or c) to diagnose disease. I have continued to use the techniques learnt from Maxwell Knight and, six decades later, they still serve me in good stead, both as a herpetologist and as a veterinary pathologist.

The skin is the largest organ in the body and examination of it, or its derivatives, plays a vital role in assessing health and wellbeing. Its crucial importance in this respect, in all species has long been recognised:

“Skin for skin! A man will give all he has for his own life”. Job 2:4

Yours faithfully

John E Cooper

University of Cambridge

References

Cooper, J.E. (1998). Minimally invasive health-monitoring of wildlife. Animal Welfare 7, 35-44.

Cooper, J.E. and Cooper, M.E. 2013. Wildlife Forensic Investigation: Principles and Practice. Taylor & Francis/CRC Press, Boca Raton, Florida, USA.

Jones, D.E., Gogal, R.M., Nader, P.B. and Holladay, S.D. (2005). Organochlorine detection in the shed skins of snakes. Ecotoxicol. Environ. Saf. 60, 282-287.

Knight, M. 1968. Be a Nature Detective. Frederick Warne, London.

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