Boa constrictor


Have you seen Boa constrictor?

Be on the lookout for Boa constrictor and report it to Biosecurity Queensland. Early detection and reporting are the key elements in controlling Boa constrictor.

Call us on 13 25 23.

Native to North, Central and South America, boa constrictors are large, non-venomous snakes. In some parts of their native range, boa constrictor numbers have been substantially reduced by human and animal predation and by over-collection for the exotic and snakeskin trades. However, most populations are not under threat of immediate extinction.

Ten subspecies of boa constrictor are currently recognised. Boa constrictors are a pest species in the USA, where feral populations have established outside the species’ native range. Boa constrictors represent a significant risk to Australia because they can carry new disease and harm native wildlife.

Biosecurity Queensland encourages people to report this pest animal and take actions to help stop its establishment, prevent its spread, and control this pest.

The boa constrictor is a prohibited invasive animal under the Biosecurity Act 2014.

Scientific name

Boa constrictor

Similar species

  • Native carpet python


  • Python up to 4m long, weighing up to 45kg (though more commonly 10-15kg).
  • Females generally longer and thicker than males.
  • Colour may vary but is generally brown, grey or cream base colour with brown or reddish-brown patterns (’saddles’) that become more pronounced towards tail.
  • Head is arrow-shaped with distinctive stripes (1 running dorsally from snout to back of head, others running from snout to eyes and eyes to jaw).


  • Found in range of habitats from tropical rainforests to arid semi-desert country.
  • Prefers rainforest due to humidity, temperature, natural cover from predators, and ready supply of prey.
  • Prefers to stay on dry land, living primarily in hollow logs and abandoned mammal burrows protected from potential predators.
  • Also capable swimmer commonly found in or along rivers and streams.
  • Frequently found close to human habitation and observed in urban and agricultural areas, including cultivated fields.
  • Unlikely to move over long distances when food and shelter are available locally.


  • Not established in wild in Queensland.

Life cycle

  • Females only reproduce when in good physical condition.
  • Females incubate and hatch eggs inside bodies, then birth up to 60 live babies (average about 25 per clutch), which are independent within minutes of birth.
  • Boas are 30-60cm long when born, then grow quickly for first few years.
  • Reach sexual maturity and adult size of 1.8-3m at 3-4 years old,  then continue to grow slowly throughout 25- to 30-year lifespan.
  • Typically solitary animals that come together only to mate.



  • Prey on small mammals, birds, amphibians and other reptiles by constricting prey to restrict movement and suffocate them. Size of prey increases as snake grows.
  • Large clutch sizes mean boa constrictors can colonise new areas relatively quickly and compete with native species for food and shelter (burrows).
  • May carry new diseases such as the fatal Inclusion Body Disease, which has been transferred from boa constrictors to native Australian pythons in captivity.


  • Strikes when perceives a threat and can cause serious injury by biting. Bite (especially from large snakes) can be painful, but is rarely dangerous to humans.


  • Control is difficult.
  • Boa constrictors are difficult to find as they are only active for limited time after dusk and prefer underground burrows or thick vegetation.
  • Trapping may be practical option.

Legal requirements

  • The boa constrictor is a prohibited invasive animal under the Biosecurity Act 2014.
  • It must not be kept, moved, fed, given away or sold without a permit.
  • The Act requires that all sightings are to be reported to Biosecurity Queensland within 24 hours.
  • By law, everyone has a general biosecurity obligation (GBO) to take all reasonable and practical steps to minimise the risk of boa constrictor escaping until they receive advice from an authorised officer.

Further information