Robert A. Valentic
Partial or full tongue loss among snakes is rare, with Hopgood (1980) providing the only published account I could locate. The account did not relate to tongue regeneration. The following observation records a gradual and complete regeneration of the severed portion of a tongue-tip.
The observations relate to an adult male Aspidites melanocephalus held between July 9th 1992 and August 22nd 1993. The tongue loss occurred on July 17th 1992 during routine feeding. In my experience pythons of this species are awkward and clumsy in both the striking and consumption of prey items. An adult Rattus rattus managed to turn whilst pinned beneath the snake, biting off one of the tongue-tips. At that moment the snake was investigating the rodents head in an effort to start the swallowing process. Despite the injury the snake continued feeding and no unusual behaviour was noticed during subsequent feeds. Four months later it was obvious that the severed tip was slowly regenerating. This was observed on any occasion that the tongue was visible. A complete tip had formed by eight months (See Figure 1) and full regeneration occurred by fourteen months.
That the python was capable of partial tongue regeneration possibly highlights the importance of, and the reliance on, chemoreception in snakes. Prey detection did not appear to be impeded by the tongue loss in the captive situation. However in the field where scents are followed over considerable distances and where potential mates, rivals and predators must be located, tongue loss could be highly disadvantageous. Neil Ford (cited by Shine, 1991. p 19.) suggested that trail following behaviour may even explain why snakes have forked tongues. “ Because its tongue has widely separated tips, a trail-following snake can always compare which of the two tongue-tips encountered the strongest scent -and hence, was closer to the centre of the scent trail.”
The genus Aspidites is unique among Australian python genera in lacking labial pits - possibly a link to their prey preferance of other reptiles. Perhaps this regeneration highlights a dependance on tongue tips in the location of prey. Further investigation into potential tongue regeneration in other reptiles is warranted.
Hopgood, J. 1980. Modification of the scenting technique in a Water Python (Liasis mackloti). South Australian Herpetological Group Newsletter. (Feb) : 4.
Shine, R. 1991. Australian Snakes - A Natural History. Reed Books, Sydney. 223pp.