Head to head

Python vs Boa

Python

Boa

Pythons and boas look alike, kill the same way, and are often confused, but they are separate families that split long ago. The most reliable difference is not in how they look but in how they reproduce, along with a few skeletal details and where in the world each group lives.

	Python	Boa
Family	Pythonidae	Boidae
Reproduction	Lays eggs, usually broods them	Live birth in almost all species
Extra jaw bones and teeth	Present (premaxillary teeth)	Absent
Heat-sensing pits	Deep pits in the lip scales	Shallower, between the scales, or absent
Native range	Africa, Asia, Australia	Mainly the Americas; sand boas in Africa and Asia
Largest member	Reticulated python, longest snake alive	Green anaconda, heaviest snake alive
Kills prey by	Constriction	Constriction
Leg remnants	Pelvic spurs beside the vent	Pelvic spurs beside the vent

The bottom line

Both pythons and boas are large non-venomous constrictors from an ancient branch of the snakes, and both kill by throwing coils around prey and tightening with each exhalation until blood flow to the heart and brain stops. The main difference is reproduction. Pythons, family Pythonidae, lay eggs, and the female usually coils around the clutch to brood it, with some species shivering to warm the eggs. Almost all boas, family Boidae, are ovoviviparous, retaining the eggs inside the body and giving birth to live young. Pythons also have a set of extra bones and teeth in the upper jaw that boas lack, and their heat-sensing organs sit in obvious pits along the lip scales, whereas a boa's are shallower and set between the scales. Geographically, pythons are an Old World group found in Africa, Asia, and Australia, while boas are centred on the Americas with a second group of sand boas in Africa and Asia. The largest python, the reticulated, is the longest snake in the world, while the largest boa, the green anaconda, is the heaviest.

Python vs Boa: common questions

What is the single most reliable way to tell a python from a boa?

Reproduction, if you can observe it. Pythons lay eggs and the female typically coils around them until they hatch, while almost every boa gives birth to fully formed live young. Short of watching them breed, the next best cues are geography and the head. A big constrictor native to Africa, Asia, or Australia is almost certainly a python, and one native to Central or South America is almost certainly a boa. Under a close look, pythons have teeth on the premaxilla at the very front of the upper jaw and usually more prominent, more numerous heat pits than boas. None of these is visible from a distance.

Is an anaconda a python or a boa?

An anaconda is a boa. The green anaconda and its smaller relatives belong to the family Boidae and give birth to live young, and they are semi-aquatic ambush hunters of South American rivers and swamps. The confusion usually comes from size, because the green anaconda and the reticulated python are the two contenders for largest snake in the world. They split the title: the reticulated python is longer, with reliable records over 6 metres, while the green anaconda is much heavier and bulkier for its length, exceeding 100 kilograms. They live on different continents and are not close relatives.

Are pythons or boas more dangerous to people?

Both are non-venomous and neither is a meaningful threat to most people, but the few genuinely large species carry some risk. Among pythons, the reticulated python and the African rock python are long and powerful enough to kill an adult, and a small number of deaths are recorded, usually involving very large wild snakes or careless handling of captives. Among boas, only the green anaconda reaches a size where it could in theory take a person, and verified cases are extremely rare. Most pythons and boas are far too small to regard a human as prey and will only bite defensively, which is painful but not dangerous.

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Published November 8, 2026 · last updated November 8, 2026.