The python and boa are among the largest snakes in the world. They have many similarities, including diet, potential life span and how they kill their prey. Their main difference is how they reproduce: The boa gives birth to live snakes, compared to the python, who lays and incubates her eggs.
There are 33 species of pythons, ranging from a short 23 inches in length to a whopping 33 feet long. The smallest python, the pygmy or anthill python, weighs around 7.4 ounces; his cousin the reticulated python can weight up to 250 pounds. A boa can be one of 41 different species, ranging from 16 inches to 30 feet long. The anaconda is the heaviest boa, hitting the scales at up to 280 pounds. Both snakes have a potential life span of approximately 35 years.
Perhaps the greatest difference between boas and pythons is how they produce their young. Boas give birth to live young. During their development, baby boas are surrounded by a clear membrane, attached to their mother's body by a yolk sac. They make their appearance through the cloaca, surrounded by the membrane they have to permeate. After they break free, they're on their own, hiding to protect themselves and searching for food. The species of boa determines how many babies she'll give birth to, as well as the gestational period. A boa may give birth to as few as four or as many as 40 baby snakes, with a gestational period ranging between 50 and 180 days.
In contrast, pythons lay eggs. The nesting spot varies based on the python and her habitat, but eggs may be laid on the ground and covered with leaves or deposited in a shallow nest. The mother snake coils atop her eggs to keep them warm, shivering if necessary to generate additional heat, known as thermogenesis. When the eggs hatch, the mother leaves, and as with baby boas, the baby pythons are left to fend for themselves. Pythons lay between two and 100 eggs, depending on the species, and the incubation period ranges between 40 and 100 days.
Habitat and Homes
Pythons don't cover as much ground as boas; they're strictly old world, found in Australia, Africa and Asia, while boas are old and new world, also found in the Americas. Given the boa's extensive territory, it's no surprise his habitat varies widely. Boas living in dry environments tend to gravitate toward underground burrows and rock crevices, while those living in forests try to hide themselves among tree bark and leaf litter. Pythons also occupy a host of different environments, including grasslands and savannas, rainforests, desert hills, woodlands and shrub lands, taking up residency in tree hollows and branches, abandoned animal burrows and rocky outcrops. The black-headed and woma pythons dig their own burrows, instead of reinhabiting an abandoned home.
Both snakes are constrictors, grasping their prey with their mouth and squeezing their coiled bodies around the prey. The prey's bones aren't broken, nor is it crushed. Instead, it suffocates because its lungs can't expand. When the snakes don't detect a heartbeat, they know it's time to eat. Both snakes swallow the prey whole, using muscular contractions to push dinner down the throat and into the stomach. Boas and pythons have a tube in the bottom of their mouths that allow them to inhale air as they eat.
What's For Dinner
Boas and pythons are ambush hunters, hiding until their target comes close enough to be taken with a quick strike. They're able to sense their prey through temperature-sensitive scales around their mouths, as they feel the animal's heat. Their sense of smell also allows them to pick up an animal's scent. Boas eat frogs, lizards, rodents, birds and small to medium-sized animals such as pigs, possums and deer. Anacondas can eat larger animals, including a young tapir. Pythons eat similarly.