Aspidites melanocephalus

Aspidites melanocephalus, also known as the Black-headed python or the Black-headed rock python, is broadly distributed throughout the northern third of Australia, extending from east to west across the continent. This range includes a majority of the Northern Territory, the northern latitudes of Queensland and the northern third of Western Australia. (Shine, 1991; Uetz, 1995; Walls, 1998)

Most often populating the dry scrublands and savannas throughout its geographic range, Aspidites melanocephalus can also be found in damper forests and agricultural farmland. It avoids the most arid environmental conditions, but can otherwise survive within a wide range of climates and conditions. Most of the time these pythons reside in either self-dug burrows or in abandoned burrows. Its fossorial tendencies allow it to keep a more constant body temperature, thus allowing it to occupy a wide range of habitat types. This species is a capable climber and is occasionally found in trees. Elevations inhabited by this species range from 50 feet above sea level to 200 feet above sea level. (Ashraf, 2011; Johnson, et al., 1975; "Pythons: Pythonidae - Black-headed Python (aspidites Melanocephalus): Species Accounts", 2011; Walls, 1998; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)

Black-headed pythons have a distinctive glossy, black hood that covers the entire cranium and extends 20 scales down the neck along the dorsal line. In juveniles, the dark pigmentation can extend even further to cover the anterior ventral scales. The rest of the body can range from sandy brown to yellow to a pale reddish tan, but normally exhibits irregular dark brown bands that can blend together along the mid-dorsal line, creating a striped appearance. There may also be small blotches between the stripes along the sides of some specimens. The venter can range from white to pink, but can also exhibit dark spots similar those along the dorsum. Coloration of Black-headed pythons can vary extensively depending on age and geographic location. For example, Western Australian specimens are much lighter with reddish overtones than those found in the Northern Territory and Queensland, which have darker, more intense striping patterns. Furthermore, while older specimens tend to be paler with less distinctive markings, younger specimens are known to exhibit markings of greater intensity. (Ashraf, 2011; Bauchot, 1997; Friend and Cellier, 1990; Johnson, et al., 1975; "Pythons: Pythonidae - Black-headed Python (aspidites Melanocephalus): Species Accounts", 2011; Shine, 1991; Uetz, 1995; "Aspidites melanocephalus (Black-headed python)", 2011; Walls, 1998; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)

Body length in black-headed pythons ranges from 1.5 to 2 m. Captive adults weigh 16 kg on average, and females can grow to nearly a foot longer than males. Body form is cylindrical and slender, with 315 to 359 ventral scales, which is more than most Australasian species of Aspidites. Black-headed pythons have a reduced head and strengthened rostral region that make it well-suited for burrowing and capturing prey. (Ashraf, 2011; Bauchot, 1997; Friend and Cellier, 1990; Johnson, et al., 1975; "Pythons: Pythonidae - Black-headed Python (aspidites Melanocephalus): Species Accounts", 2011; Shine, 1991; Uetz, 1995; "Aspidites melanocephalus (Black-headed python)", 2011; Walls, 1998; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)

Moderate isolation between populations of black-headed pythons has resulted in poorly defined population-distinguishing characteristics. Inter-population differences include the pairing of parietal bones (one pair in western populations and two to three in other populations), as well as fewer loreals and suboculars in western populations in comparison to their eastern counterparts. (Ashraf, 2011; Bauchot, 1997; Friend and Cellier, 1990; Johnson, et al., 1975; "Pythons: Pythonidae - Black-headed Python (aspidites Melanocephalus): Species Accounts", 2011; Shine, 1991; Uetz, 1995; "Aspidites melanocephalus (Black-headed python)", 2011; Walls, 1998; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)

In the wild, bleack-headed pythons reach sexual maturity by 4 to 5 years after hatching, however, captive individuals have been bred as young as 2.5 years. Younger individuals generally have lower reproductive success than older individuals. On average, hatchlings are .6 m in length and can capture their own prey by two days after birth. (Ashraf, 2011; Bauchot, 1997; Johnson, et al., 1975; Madec and Madec, 2011; Shine, 1991; Uetz, 1995; Walls, 1998)

Although black-headed pythons are seasonally monogamous, both males and females may seek extra-pair copulations. Male black-headed pythons are not as aggressive as most pythonids, which frequently engage in male to male combat. However, some instances of combat have been recorded. Although this species is large and is relatively common throughout much of its geographic range, individuals are rarely observed, leading to a limited number of studies on this species. (Johnson, et al., 1975; Madec and Madec, 2011; TercafsSource, 1963; Uetz, 1995; "Aspidites melanocephalus (Black-headed python)", 2011; Walls, 1998; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)

Aspidites melanocephalus females incubate their eggs, which are laid during October and November, by coiling around them for approximately 2 months before they hatch. Males are not as aggressive as most pythonids, though mating and courtship often involve male-male competition, which may include combative sparring or biting. In captivity, males paired with a single female have the highest mating success rate. Copulation can range from 20 minutes to 6 hours and a single clutch can range from 8 to 18 offspring. Young become reproductively mature by 4 to 5 years of age. (Bauchot, 1997; Friend and Cellier, 1990; Johnson, et al., 1975; Kluge, 1993; "A Listing of Australian Pythons: SERPENTES (SNAKES)", 1997; Shine, 1991; Walls, 1998)

Aspidites melanocephalus is oviparous,laying from 8 to 18 eggs during October and November. Eggs averages 8.9 cm in length. After 2 months of incubation by the mother, hatchlings emerge and are completely independent. (Madec and Madec, 2011; Uetz, 1995; Walls, 1998; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)

The lifespan of Aspidites melanocephalus ranges from 20 to 30 years. No differences between the lifespans of wild and captive individuals has been documented. (Shine, 1991; Walls, 1998; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)

Black-headed pythons are nocturnal and are well-adapted for surviving in hot, dry conditions. During cooler temperatures, evidence suggests that when termite nests are present, they tend to burrow into these habitats as a way of maintaining a stable body temperature. When termite mounds were not present, they adopted specific postures and modified their behavior to prevent extreme cooling. The glossy, black head that is characteristic of this species helps regulate body temperature as well, allowing the majority of the snake’s body to remain hidden while it extends only its head from its burrow. In order to cool themselves, they may bury their dark head in the sand. When disturbed, black-headed pythons occasionally hiss, but rarely bite. They may also strike with their mouths closed when threatened. Similar to other pythons, black-headed pythons constrict their prey to kill it prior to ingestion. They are adept swimmers; however, in the wild it is not common to find them in water. (Ashraf, 2011; Bauchot, 1997; Friend and Cellier, 1990; Kluge, 1993; Madec and Madec, 2011; "Pythons: Pythonidae - Black-headed Python (aspidites Melanocephalus): Species Accounts", 2011; Shine, 1991; Walls, 1998)

There is no information available regarding the average home range of black-headed pythons.

Members of the genus Aspidites have entirely lost supralabial and infralabial sensory pits, which are used for heat sensing of endothermic prey or to detect small changes in local temperatures. The absence of heat sensing pits in this species marks a significant difference between the strategies employed for prey capture and perception than those employed by other pythons. There is no further information available regarding communication and perception in this species, however, it is probable that tactile, olfactory, and visual cues play an important role in communication and perception in black-headed pythons. (Ashraf, 2011; "Pythons: Pythonidae - Black-headed Python (aspidites Melanocephalus): Species Accounts", 2011; Shine, 1991; "Aspidites melanocephalus (Black-headed python)", 2011; Walls, 1998)

The diet of Black-headed pythons primarily consists of other reptiles. Skinks are the primary prey of black-headed pythons. Other important prey includes geckos, bearded dragons, legless lizards and Perentie, the largest monitor lizard native to Australia. Small snakes, including some venomous snakes are also consumed by black-headed pythons, which are completely impervious to the venom found in even the most toxic Australian snakes. Consumption of mammals and some birds is rare but does occur in nature. Because Black-headed pythons lack venom, they utilize constriction to subdue large prey prior to consumption. (Kluge, 1993; Madec and Madec, 2011; "Pythons: Pythonidae - Black-headed Python (aspidites Melanocephalus): Species Accounts", 2011; Shine, 1991; Uetz, 1995; Walls, 1998)

The major predators of black-headed pythons include dingos and humans. When threatened, black-headed pythons may strike with their mouth closed. Their nocturnal and fossorial nature likely reduces predation risk, and their coloration helps camouflage them from potential predators. (Ashraf, 2011; Kluge, 1993; Madec and Madec, 2011; "Pythons: Pythonidae - Black-headed Python (aspidites Melanocephalus): Species Accounts", 2011; Shine, 1991; TercafsSource, 1963; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)

As an important predator for a number of different reptile species, black-headed pythons play an important role in the north Australian food web. In addition, the burrows created by this species are sometimes used by other animals once they are abandoned. There is no information available regarding parasites of this species.

The combination of habitat choice, burrowing behavior, and primarily nocturnal activity of Aspidites melanocephalus makes interaction with humans unusual such that neither group substantially affects one another. However, sales of Black-headed pythons as pets and for other domestication and breeding purposes has become relatively common throughout northern Australia. (Madec and Madec, 2011; "A Listing of Australian Pythons: SERPENTES (SNAKES)", 1997; Shine, 1991; Uetz, 1995; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)

There are no known adverse effects of black-headed pythons on humans.

Black-headed pythons have not been evaluated by the IUCN. There is little information available regarding the population trends of this species, thus potential conservation and management needs are difficult to identify. They are considered widespread and locally abundant throughout their geographic range. The only foreseeable potential threat to this species is the pet trade; however, a large majority of animals in the pet trade are captive bred. (Ashraf, 2011; Uetz, 1995; Walls, 1998; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)

Another name for this species is the Purruyura, which is a term used by the Nyangumarta aboriginals in the Pilbara region. Other common names for this species include “tar pot,” “Terry tar pot,” and “rock python”. The term tar pot derives from the distinctive markings of shiny, black scales on the head and neck that give the appearance that it has been dipped in a vat of tar. (TercafsSource, 1963; "Eastern Black-Headed Pythons: Aspidites melanocephalus", 2002)