AsianScientist (Sep. 24, 2015) – The Brahminy blind snake, Indotyphlops braminus has been shown to decapitate its prey before ingestion. The authors suggest that this behavior—previously only recorded in four other species—could be an adaptation to save gut space during ingestion or to avoid toxic chemicals in the head segments of termites.
The results, published in the Journal of Zoology, showed that the snake only eats the thorax and abdomen of their termite prey in 47 percent of feeding trials while the rest of the time prey were swallowed whole.
If there is one thing most people think they know about snakes, it is that snakes swallow their prey head-first and whole. Prior to the present study, only a few species from two families (Colubridae and Leptotyphlopidae) were known to dismember their prey before consuming it.
Common names for Indotyphlops braminus include Brahminy blind snake and flowerpot snake; so named because flowerpots are where they are commonly found in most parts of the Old World and recently introduced in the New World. The species is one of the smallest snakes in the world with a maximum snout-vent length of 20 cm and is occasionally mistaken for an earthworm.
It is also known to exhibit parthenogenesis—population sex ratio is 100 percent female and reproduction is asexual. They are fossorial snakes, spending most of their time underground to ‘binge feed’ on ants, termites and other arthropods.
The authors—a herpetologist from the University of Kyoto and an entomologist from the Kyoto Institute of Technology—were conducting experiments involving blind snakes and its most common prey, ants. The termite species Reticulitermes speratus was also used to feed the snakes and the authors then observed the strange behavior of snakes, ingesting the termites abdomen first so that the head would be swallowed last. Using the bottom surface as leverage, the snakes were observed scraping at the head segment until it detached.
Intrigued, the Dr. Yosuke Kojima and his student Mr. Takafumi Mizuno set up feeding trials on seven snakes. Ninety five worker and five soldier termites (which represented the average ratio of workers to soldiers in a termite colony) were fed to each snake. Infra-red video cameras recorded the events and fecal matter was analysed microscopically to determine the number of undigested termite heads.
A total of 210 decapitation events occurred, with 48 percent of all termite workers being decapitated. Only two of the seven snakes ate soldiers (which have larger mouth parts and are more aggressive compared to workers) and all the soldiers, which were newly moulted, had been decapitated. Some snakes were also observed to partially regurgitate the heads of termites before either decapitating or re-swallowing them.
The scientists also found that decapitation had no effect on ingestion speed. However, incidences where termites were swallowed head first, ingestion speed increased by almost half.
So what might explain this exceptional ingestion behavior? While the authors found that decapitation comes at a cost of lower ingestion speed, they posit two hypotheses: decapitation is an adaptation to either save space in the gut as the head segments appear to be indigestible or to avoid ingestion of toxic compounds found in termite head segments.
These findings shed light on a basal group of snakes known as Scolophidia, which has more than 400 species but of which feeding ecology poorly known. I. braminus belongs to the Typhlopidae family which is ecologically and morphologically similar to the Leptotyphlopidae, but differs from members of that family in its feeding mechanism. The former ‘rake’ their prey in with asynchronous movements of their highly mobile upper jaws while the latter use bilaterally synchronous movements of their lower jaws, as elaborated in an earlier study.
The article can be found at: Mizuno and Kojima (2015) A Blindsnake that Decapitates its Termite Prey.
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Copyright: Asian Scientist Magazine; Photo: Takafumi Mizuno.
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