Ecology Of Snakes

This essay is about the impacts of foraging mode on the morphology, physiology, behaviour and ecology of snakes. But before exploring the impacts, need to understand how or why snakes select particular habitats, be it a desert, grassland, rainforest, aquatic, etc. Habitat choice is important for snakes to be able to survive and reproduce (Huey and Pianka 1981). To achieve this they need food/prey, hence foraging mode (food that an animal eats and the way it obtains it) is central to their ecology (Slip and Shine 1988).

Snakes have managed to diversify into large number of species occupying large ecological habitats (Huey 1991). It is important to note that snakes have undergone adaptive measures since their origin in order to fit into a selected

2002). Again through evolution, small modifications in jaw apparatus allowed snakes the ability to ingest large prey mass (Cruz-Neto et al. 1999). Snakes share the same general body plan characterized by elongated trunk and lack of limb features that influence many aspects of a snake’s biology, including aid in thermoregulation and movement (Canjani et al. 2002). The body elongation is associated with decreased cross sectional area used for food acquisition (example gape of mouth relative to body size) (Canjani et al. 2002). The skulls also possess many distinctive bony and muscular adaptations that facilitate swallowing of large prey (Canjani et al. 2002). These same morphological specializations made the skull a mobile loose structure that is incapable of handling large prey. The direct contact with land by terrestrial snakes allows them to better exchange heat. This was a result of trade-offs or cost benefit analysis through evolution which had to be balanced (Naulleau and Bonnet 1995). Reproduction and survival of a population are prioritized in trade-offs, as seen with maternal body length been larger than males and showing positive influences on the number of eggs laid per female (Naulleau and Bonnet

2006). These structural responses are seen mostly in snakes that feed at intermittent intervals, as in ambush foragers (Secor and Diamond 1995). Such snakes must be able to restore digestive function soon after feeding and this transition occur at low metabolic costs. Ambush foragers have adapted by rapidly up regulating their intestines in response to feeding (Secor and Diamond 1995). This consumes energy and has to therefore be perfectly timed. For example, pregnant female snakes may omit to feed before giving birth (Secor et al. 1994). Also, pregnant females and snakes that just consumed prey exhibit decreased sprint speed and low endurance which is not ideal because then they can’t move fast to evade predators (Ford and Hampton 2009).

Ambush foragers compensate for low meal frequency by capturing and consuming a large meal size (Secor et al. 1994). They have slow digestion, intestines that have adapted to been inactive for long time and after consuming a large meal they spend a long time digesting it (Secor et al. 1994). Intestines that are active have high maintenance costs because enterocytes have one of the most rapid turnover rates of any tissue therefore expect fasting snakes to save energy by down regulating gut activities and up regulating rapidly upon prey capture (Secor et al. 1994, Secor and Diamond 1995, Secor