Sea Snake Harvest in the Gulf of Thailand : Sea Snake Harvest

Traditional Chinese medicine (TCM) has been increasingly practised in many countries of the world. Some recent textbooks of TCM still recommend formulas containing various animal tissues such as tiger bones, antelope, buffalo or rhino horns, deer antlers, testicles and os penis of the dog, bear or snake bile. Usually, animal tissues are combined with medical herbs. In most of the cases, the medical use of the preparations is justified in terms of the rules of TCM. So far, little research has been done to prove the claimed clinical efficacy of TCM animal products. This paper discusses some related ecological, ethico-legal and health concerns such as hunting, breeding and trade with endangered species, risks of transmission of zoonoses, quality of the products, and alternatives to preparations from endangered species.

Studies so far have correlated the variation in the composition of snake venoms with the target prey population and snake's diet. Here we present the first example of an alternative evolutionary link between venom composition and dietary adaptation of snakes. We describe a dinucleotide deletion in the only three finger toxin gene expressed in the sea snake Aipysurus eydouxii (Marbled Sea Snake) venom and how it may have been the result of a significant change in dietary habits. The deletion leads to a frame shift and truncation with an accompanying loss of neurotoxicity. Due to the remarkable streamlining of sea snake venoms, a mutation of a single toxin can have dramatic effects on the whole venom, in this case likely explaining the 50- to 100-fold decrease in venom toxicity in comparison to that of other species in the same genus. This is a secondary result of the adaptation of A. eydouxii to a new dietary habit--feeding exclusively on fish eggs and, thus, the snake no longer using its venom for prey capture. This was parallel to greatly atrophied venom glands and loss of effective fangs. It is interesting to note that a potent venom was not maintained for use in defense, thus reinforcing that the primary use of snake venom is for prey capture.