Antaresia perthensis

Antaresia perthensis, commonly referred to as the pygmy or anthill python, is native to the Pilbara region of northwest Australia and occasionally in northwest Queensland. This species is normally seen outside of Australia only as a part the lucrative reptile pet trade. However, outside its native range, A. perthensis appears to adapt easily to many different environments. (Hardy, 1995; Hoser, 2000)

Pygmy pythons are abundant and widespread throughout the Pilbara. The Pilbara region is south of the Kimberly Tropical Savanna ecoregion and includes some of the hottest and driest areas of Australia. Although this region is extremely arid and has no formal wet or dry season, the small amount of rainfall that occurs is typically concentrated in the summer season. This habitat is composed mostly of flat land with sparse vegetation, which is generally composed of either Spinifex bushes (small grassy bushes which cover small rocky hills) or stunted eucalyptus trees.

Herpetologists find pygmy pythons by burning spinifex bushes, where they often hide in the bushes during the day to escape the blazing Australian sun. This snake is most easily found in large termite mounds, where they spend almost all daylight hours. Normally, A. perthensis is found sharing the large mounds with other species, including Stimson's pythons (Antaresia stimsoni), black-headed pythons (Aspidites melanocephalus), king brown snakes (Pseudechis australis), moon snakes (Furina ornate), broad-banded sand swimmers (Eremiascincus richardsoni), Pilbara geckoes (Gehyra purpurascens), and depressed spiny skinks (Egernia depressa). It has been suggested that A. perthensis frequents these mounds because daytime temperatures in the mounds can reach up to 38 C, which are ideal conditions for these ectothermic pythons. While inside the mounds, A. perthensis and other snakes curl around each other into what looks like a large ball. Time spent in the mounds is normally used to rest and convert the heat around them into energy. In addition to spinifex bushes and termite mounds, A. perthensis can occasionally be found under rocks. (Government of Western Australia, 2009; Hoser, 1993; Hoser, 1995; Hoser, 1999; Hoser, 2000)

Pygmy pythons are the smallest pythons in the world, measuring only about 60 cm long and 200 g as an adult. At the time of hatching, this tiny snake is only about 17 cm long and 4 g. Females are slightly larger than males. The head is short and wedge shaped, while the neck and body are thick and muscular. The dorsal side is typically dark brick red and may be patterned. The pattern is made of approximately four regular black markings which give the impression of crossbars. Generally patterns and colors are brighter and more vivid in younger snakes, sometimes fading completely at maturity. On the ventral surface pygmy pythongs are creamy white. The scalation is as follows: 31-35 mid body rows, 205-255 ventral scales, a single anal scale, and 30-45 subcaudals.

All pythons, including A. perthensis, move by traveling forward in a straight line, known as rectilinear progression. This is accomplished by stiffening their ribs, to provide support, then lifting a set of ventral scales and moving them forward so the loose ends grip the surface of the ground, pushing the snake forward. This type of movement works on the ground as well as in trees. (Bartlett and Wagner, 1997; Bradshaw, 2000; Hoser, 1993; Hoser, 1995; Hoser, 2000; Mattison, 2007; Seigel, et al., 1987; "Pythons, boas, and anacondas, whats the differance", 2010)

Ensuring that A. perthensis eggs are incubated at sufficient temperatures is essential to the success of the eggs. Python eggs are particularly temperature sensitive and, if incubated at insufficient temperatures, many young fail to develop or develop birth defects such as spinal kyphosis. Cooler incubation temperatures can also result in abnormalities in a darkening or color or the presence of a stripped pattern. To aid in the hatching process, A. perthensis have a small egg tooth on the end of their nose. The egg tooth helps the hatching snakes to break through their tough shells and will fall off within a few weeks of hatching. (Bartlett and Wagner, 1997; Hoser, 1995; Hoser, 2000; Mattison, 2007; Seigel, et al., 1987)

Like most small snakes, pygmy pythons exhibit a trait called pairing behavior, where multiple males and females move about together. It is believed that this behavior is a result of males following the females specifically to mate, in response to a release of pheromones by the female. The female snake releases these pheromones in response to a drop in the surrounding temperature. Males rub their bodies along the female’s cloacal spurs, which are used to initiate the breeding response in females. This helps to entice the female before begining coppulation.The reproductive organs of male snakes are paired, forked hemipenes, which are stored, inverted, in the male's tail. The hemipenes are often grooved, hooked, or spindled in order to grip the walls of the female's cloaca. (Bartlett and Wagner, 1997; Seigel, et al., 1987)

This species is oviparous and lay eggs that are encased in a thin parchment-like shell. The eggs take about 2 months to hatch, during which time the mother python will stay coiled around her eggs to provide protection and warmth. (Bartlett and Wagner, 1997; Hoser, 1995; Hoser, 1999; Mattison, 2007; Seigel, et al., 1987)

While there are no accounts of parental investment in the wild, female pythons generally stay coiled around their eggs to protect them while they develop, ensuring that the eggs do not get too cold. Once the eggs hatch, the young are independent. (Bartlett and Wagner, 1997; "Pythons, boas, and anacondas, whats the differance", 2010)

Pygmy pythons are known to live more than 25 years. Although these snakes do not live as long in captivity, they still have a fairly long life span, up to 20 years. (Bartlett and Wagner, 1997; Government of Western Australia, 2009; Hoser, 1989; Hoser, 1995; Mattison, 2007; "Pythons, boas, and anacondas, whats the differance", 2010)

Pygmy pythons are largely solitary, only being found with other pygmy pythons during the mating season. Although these snakes are often found with other aggregations of snakes in termite mounds, these are opportunistic aggregations and there is little interaction. (Seigel, et al., 1987)

Home range sizes have not been reported.

Pygmy pythons use scent to track their prey. They flick their forked tongues to collect airborne particles, then passing them to the vomeronasal or Jacobson's organ in the mouth. This fork in the tongue gives snakes a sort of directional sense of smell and taste simultaneously. Their tongues are kept it constant motion, sampling particles from the air, ground, and water, analyzing the chemicals found, and determining the presence of prey or predators in the local environment Pit vipers, pythons, and some species of boas have infrared-sensitive receptors in deep grooves between the nostril and eye. Also common in pythons are labial pits that are found on their upper lip just below the nostrils, these structures allows them to "see" the radiated heat of warm-blooded prey mammals. Pygmy python underbellies come in direct contact with the ground and are very sensitive to vibrations. This allows snakes to sense other animals approaching by detecting the faint vibrations in the air and on the ground. Research suggests that A. perthensis communicates like most other snake species, using mainly scent to find prey and communicate. (Bartlett and Wagner, 1997; Hoser, 1995; Seigel, et al., 1987)

Pygmy pythons kill prey by constriction. Though constriction appears to involve continuous squeezing, it actually occurs intermittently. Since muscles use large amounts of energy when they exert force, squeezing intermittently and only when necessary, the snakes conserve energy. Holding the constriction posture even when not squeezing allows a snake to squeeze again very quickly if the prey starts to move again.

Pygmy pythons are nocturnal hunters, hunting at night helps them to avoid the extreme temperatures experienced during the day in the Pilbara region. Their diet changes with age: young snakes generally eat small reptiles including geckos and skinks, at maturity their diet shifts to include small mammals, such as bats which it catches in an innovative way. The snake positions itself on ledges at cave entrances and strike at the bats as they fly in and out of the caves. Adult snakes also feed on amphibians. Digestion begins almost as the snake starts the swallowing process, because the saliva and stomach acids, which completely covers the prey, contains strong enzymes for breaking down food. The amount of time needed for digestion is heavily dependent on meal size and meal type, some meals can take extremely long, sometimes multiple days to digest. (Bartlett and Wagner, 1997; Hoser, 2000; Mattison, 2007; Shine and Slip, 1990)

Pygmy python young are at high risk of predation. These snakes are eaten by a variety of birds, carnivorous mammals, large frogs, spiders, and other snakes. Though adult pygmy pythons are at a slightly lower risk, their small size still makes them easy prey. The dark red color of this species helps them to avoid capture somewhat, as it helps them to blend with their environment. (Bartlett and Wagner, 1997; Hoser, 1995; "Pythons, boas, and anacondas, whats the differance", 2010)

Little is known about A. perthensis in the wild. While they are eaten by larger reptiles, mammals, and birds, they are not the primary prey of any known species. (Hoser, 1989; Hoser, 1993; Hoser, 2000; "Pythons, boas, and anacondas, whats the differance", 2010)

While there is no direct benefit to humans, A. perthensis does eat other small, sometimes pestilent reptiles and small mammals. In fact, they are generally docile snakes and are sought after as pets. (Hoser, 1989)

There are no known adverse effects of A. perthensis on humans. (Bartlett and Wagner, 1997)

Pygmy pythons are common throughout their natural habitat. The only significant threat to A. perthensis populations are cars and tourism, as they often cross roads during peak hours of the day. In addition, there have been increased attempts at smuggling this species out of Australia, an offense which is punishable by large fines and jail time.

Pythons (Pythonidae) are considered "primitive" snakes, with features that link them to their four-legged lizard ancestors. These features include a rudimentary pelvic girdle in the form of cloacal spurs and two equal sized lungs. (Bartlett and Wagner, 1997; Bradshaw, 2000; Hoser, 1993; Hoser, 1995; Hoser, 2000; Mattison, 2007; Seigel, et al., 1987; "Pythons, boas, and anacondas, whats the differance", 2010)