The image on the cover of Python for Unix and Linux System Administration is a boa
constrictor (boa constrictor). Found throughout South and Central America and some
islands in the Caribbean, boa constrictors are non-venomous snakes that can thrive in
a wide array of environments, from deserts to open savannas and wet tropical forests,
but they prefer arid terrain over wet surroundings. They are both terrestrial and arboreal,
but as they get older, they tend to spend more time on the ground.
Boa constrictors have very unique markings that include diamond- and oval-like patterns.
Their scales change colors depending on their habitat, allowing them to hide
from the forest-dwelling animals that hunt them.
In the wild, boa constrictors thrive on small- to medium-size rodents, lizards, bats,
birds, mongooses, squirrels, and have even been known to feast on other mammals as
large as ocelots. Being cold-blooded and slow moving, boas can go up to a week without
eating after capturing large prey. They are solitary and nocturnal hunters, with heatsensitive
pads on their heads to help them hunt. Particularly fond of bats, boas will
hang in trees and from the mouths of caves waiting for them to fly by, then they can
grab the bats with their mouths. Not surprisingly, boa constrictors kill by constriction.
The snake wraps its body around its prey in coils, tightening its grip each time the victim
breathes out, eventually suffocating it to death.
Boas are a common attraction in zoos, and they are even relatively common pets. In
fact, thousands of dollars are made every year importing them into the U.S. In South
America, they are revered as “destroyers of rodents” and are often domesticated for
that reason. Boa constrictors grow quite tame in captivity and can live there as such for
20–30 years. Hunted for the exotic pet trade and their decorative markings, some boa
constrictors are endangered and have protected status.
Boa constrictors are seasonal breeders. To attract males, females emit a scent from their
cloacas, which is the chamber into which the intestinal and urogenital tracts discharge.
Fertilization happens internally, and females can give birth to up to 60 live babies at
one time. Significantly smaller than their anaconda cousins, newborn boas average 2
feet in length and can grow up to 13 feet long and weigh more than 100 pounds. Found
in South America, the largest boa constrictor on record was 18 feet!