Feeding Habits of the Diamond Python, Morelia s. spilota: Ambush Predation by a Boid Snake

Diamond pythons (Morelia s. spilota) are large (to 3 m) snakes of temperate-zone coastal eastern Australia. Foraging behavior was studied by observation of telemetered snakes, and diets determined by dissection of museum specimens and collection of fecal samples from wild-caught snakes. Five adult snakes monitored in the field by radiotelemetry were found to be ambush foragers. In summer, telemetered snakes spent more than 80% of their time coiled, usually in a disinctive ambush posture near mammal trails. Telemetered snakes found feeding had occupied the site for at least a day beforehand. The diet of adult diamond pythons consisted almost entirely of mammals (91% of 44 records), mainly Rattus rattus and R. fuscipes (52%). Birds (9%) were taken infrequently. Juveniles ate mainly mammals (69%) and reptiles (23%). Larger snakes consumed larger prey. Hatchlings in captivity showed a preference for coppertailed skinks, Ctenotus taeniolatus, but would also take newborn mice. Feeding occurred mainly in late spring, summer and early autumn. In terms of feeding biology, diamond pythons may be more similar to viperid snakes of other continents than to the elapids or colubrids with which they are sympatric. -0; The food that an animal eats, and the way it obtains that food, are central aspects of a species' ecology, Trophic interactions may influence the distribution and abundance of a predator (and perhaps its prey), and certainly will directly affect daily activity P'!~terns and habitat use, Foraging behavior may determine rates of energy intake and survivorship, and hence may have wide-ranging effects on life-history variables, either as direct phenotypic effects, or as a basis for the evolution of modified morphology, physiology, behavior or reproductive biology (e.g, Vitt and Congdon, 1978; Ballinger, 1983). Feeding habits of snakes are of particular interest, as they show remarkable adaptations for locating, capturing, subduing and ingesting very large prey items (see Pough, 1983). Available published data on snake foraging are concerned primarily with active searching predators belonging to the families Colubridae and Elapidae (e.g. Godley, 1980; Greene, 1984). Sit-and-wait (ambush) predation also is common in snakes, but has been described in detail only for viperids (e.g. Reinert et aI., 1984; Duvall et aI., 1985). Boid snakes are widely distributed in tropical and subtropical areas throughout the world, but have attracted little scientific study under field conditions. These snakes are of interest from several points .F