The green tree python (Morelia viridis) is a species of snake in the family Pythonidae. The species is native to New Guinea, some islands in Indonesia, and the Cape York Peninsula in Australia. First described by Hermann Schlegel in 1872, it was known for many years as Chondropython viridis. As its common name suggests, it is a bright green snake that can reach a total length (including tail) of 2 m (6.6 ft) and a weight of 1.6 kg (3.5 lb), with females slightly larger and heavier than males. Living generally in trees, the green tree python mainly hunts and eats small reptiles and mammals. It is a popular pet, and numbers in the wild have suffered with large-scale smuggling of wild-caught green tree pythons in Indonesia. Despite this, the green tree python is rated as least concern on the IUCN Red List of endangered species.
The green tree python is characterized by a relatively slim body. The relatively long tail accounts for about 14% of the total length. The head is large and clearly defined from the neck. The snout is large and angular. The body is triangular in cross section with a visible spine. The species usually reaches a total length (including tail) of 150–180 cm (4.9–5.9 ft), but large females may reach 200 cm (6.6 ft). The size also varies depending on the region of origin. The weight is highly dependent upon the nutritional status of the animal. Males can weigh about 1,100–1,400 g (2.4–3.1 lb), females up to 1,600 g (3.5 lb), although wild specimens are typically much lighter than this. Especially large specimens that can weigh up to 2,200 g (4.9 lb) are invariably females, which, like most snakes, are slightly larger and heavier than males.
The green tree python is often bred and kept in captivity, although it is usually considered an advanced species due to its specific care requirements and generally irritable temperament. However, with proper care, it usually thrives in captivity. It is a popular species among reptile enthusiasts and breeders on account of its adult and juvenile colours. This has led to large numbers being illegally caught in the wild to the detriment of native populations. Transport is hazardous to the snakes’ health and up to half are thought to perish in the smuggling process. The species is protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora with its placement on the Appendix II list of vulnerable species, which makes the import, export, and trade of listed wild-caught animals illegal. In 1999, it was fully protected under national legislation in Indonesia.
Despite this, a flourishing illegal trade continues, and wildlife breeding farms were found to be serving as conduits to funnel wild-caught green tree pythons out of Indonesia. Investigation in the provinces of Maluku, West Papua, and Papua from 2009 to 2011 revealed that 80% of green tree pythons exported were caught in the wild, an estimate of around 5337 individuals a year. Harvesting of wild green tree pythons was heaviest in Biak and neighbouring islands, with resulting population decline.