The anaconda must eat its prey whole and lives primarily on wild animals such as deer, capybara, caiman and small mammals. The anaconda is completely carnivorous, eating only meat. Because the snake must eat its prey head first, most prey dies from suffocation or drowning. The jaws of these large reptiles are hinged and can open around prey twice the snake's size. The prey then moves through the snake's body through vibrations. Most of the anaconda's hunting is done in water to facilitate easier movement of the large reptile.
Like all snakes, anacondas are cold-blooded, with body temperatures close to the temperature of the environment around them. An anaconda's body temperature must match that of the water in which it is swimming to protect the animal from hypo- or hyperthermia (conditions of being too cold or too hot). Once back on land, the snake's temperature must match the temperature of the air or the soil to prevent it from getting too hot or too cold.
The anaconda lives in the rainforest, which has a variety of rivers and water sources. Because their weight makes them so sluggish on land, anacondas must spend much of their time in water and they are adept swimmers. The anaconda has nostrils atop its head to facilitate easier breathing while swimming. Because they are nocturnal, they must do most of their hunting at night. They are perfectly colored in browns, greens, tans and blacks to match the environment around them making them difficult to spot in both water and vegetation.
Anacondas reproduce the way many snakes do; they are ovoviviparous, producing eggs that they do not lay. To protect the young, the eggs hatch within the female and are released. Anacondas remain solitary and do not interact with the opposite sex until the time of reproduction, which occurs during the wet season of April/May. Male snakes remain with the female for up to 4 weeks, sometimes several males with one female to ensure mating occurs. Anacondas do not raise their young, leaving the newly born 2-foot-long snakes to fend for themselves.