Reptiles
Python
Pythonidae · also called pythons
A python kills without venom and without a fight it can lose. It waits, strikes, throws its coils around the animal, and tightens a little more each time the prey breathes out, until the blood stops moving. Then it swallows the whole thing, however much wider than its own head that thing may be.
Overview
Pythons are the family Pythonidae, around 40 species across Africa, Asia, and Australia. They are non-venomous constrictors, from the 60 cm pygmy python to the reticulated python, the longest snake alive at over 6 m. All are egg-layers, most have heat-sensing pits along the lips, and many are excellent climbers or swimmers.
How constriction works
Older books say a python suffocates its prey. Newer work shows the coils tighten with each exhalation and that death comes mainly from loss of blood flow to the heart and brain, which drops the animal unconscious within seconds. The snake senses the prey’s heartbeat and only releases when it stops. Because the kill is fast, the risk of injury from hooves, claws, or teeth is kept short.
A skull that comes apart
A python’s lower jaw is split into two halves joined by stretchy ligament, and the skull bones are loosely hinged, so the snake can open its mouth very wide and advance each side of its jaw separately, walking its head over the meal. Backward-curved teeth stop the prey slipping out. The stomach then produces enough acid to dissolve bone, and a large python may not need to feed again for months.
Brooding mothers and leftover legs
Female pythons coil around their eggs for the whole incubation, and some shiver to warm them — rare care for a snake. Pythons also keep tiny remnants of a pelvis and hind legs, showing outside the body as small claw-like spurs beside the vent, which males use in courtship.
Status
Pythons as a family are Not Evaluated. Some are common or even invasive — the Burmese python now infests the Florida Everglades — while others, such as the Indian python, are declining from skin hunting, the pet trade, and habitat loss.
Python: common questions
What is the difference between a python and a boa?
Both are large non-venomous constrictors from an ancient branch of the snakes, and they look and hunt alike, but they are separate families with a few consistent differences. Pythons lay eggs and usually brood them, while almost all boas give birth to live young. Pythons have a set of extra bones and teeth in the upper jaw that boas lack, and most pythons have obvious heat-sensing pits in the lip scales, whereas in boas these are shallower or absent. Geographically, pythons are an Old World group found in Africa, Asia, and Australia, while boas are centred on the Americas, with a few in Africa, Madagascar, and the Pacific.
Are pythons dangerous to humans?
Most are not. The great majority of python species are too small to regard a person as prey and will only bite defensively if cornered, which stings but is not dangerous. The exceptions are the few giants, mainly the reticulated python and the African rock python, which are long and powerful enough to kill and swallow an adult human, and a small number of such deaths are recorded, usually involving very large wild snakes or captive animals handled carelessly. Even these attacks are rare, and a python gains nothing from targeting people, who are difficult and risky prey compared with a pig or a deer.
How can a python swallow something bigger than its head?
Its skull is built to come apart. The two halves of the lower jaw are not fused at the chin but joined by an elastic ligament, so they can spread sideways, and the jaw bones are linked to the skull through a loose, double-jointed hinge that lets the whole mouth open very wide and move each side independently. The snake hooks its backward-pointing teeth into the prey and then walks its jaws over it, one side at a time, while the skin of the neck and body stretches enormously. Slow rhythmic muscle waves then push the meal down to the stomach.
Why are Burmese pythons a problem in Florida?
They are an invasive species, descended from pets released or escaped in South Florida from the 1980s onward, and they have found the Everglades close to ideal, with a warm climate, water, cover, and abundant prey and no natural predators or diseases from home. A female can lay dozens of eggs a year, and the population has grown into the tens of thousands. Studies in the worst-hit areas have recorded steep declines in raccoons, opossums, rabbits, and marsh birds, and the snakes also eat wading birds and alligators. Control now relies on paid hunters, detector dogs, and tracking of radio-tagged males to breeding aggregations.