Green Anaconda

## Heavy-duty snake

The name anaconda actually refers to the *Eunectes* species of snakes, but it is most often used to refer to one species, the green (or common) anaconda. A member of the boa family, South America’s green anaconda is the heaviest snake in the world.

The green anaconda is normally some shade of brownish-green, olive, or grayish-green and patterned with egg-shaped black spots. The Beni, or Bolivan, anaconda is similar but is found only in a small region of Bolivia. The smaller yellow anaconda has a pattern of blotches, saddles, spots, and streaks (usually black or dark brown) against a yellow, golden-tan, or greenish-yellow background. The dark-spotted anaconda is about the same size as the yellow anaconda and is brown with large dark spots.

## The water's fine!

Anacondas like to be in or near water, and they are excellent swimmers and divers. Their eyes and nasal openings are on top of their head, so the snakes can wait for prey while remaining nearly hidden by the water. Anacondas rest and sun themselves in tree branches that hang over water along riverbanks, so the snakes can quickly dive into the water below if needed.

## Main squeeze

These snakes don’t reach their massive size by eating salads: their diet consists of wild pigs, deer, birds, turtles, capybaras, caimans, and even jaguars.

Like its boa brethren, the anaconda kills its prey by coiling its muscular body around the creature and squeezing until the animal can no longer breathe. Jaws attached by stretchy ligaments allow the snake to swallow its prey whole, no matter the size. Anacondas can go weeks or months without eating, following a big meal.

At the San Diego Zoo, our anacondas eat pre-killed rodents and rabbits.

## The birds and the bees and the breeding ball

Anaconda courtship often lasts several weeks during the spring season. The female is thought to leave a scent trail to attract a male, but she may also produce some sort of airborne chemical signal. Researchers have observed that adult female anacondas do not move around much during the breeding season, yet males seem to flock to them from all directions. The males constantly taste the air with their tongue to pick up a female’s scent messages.

Surprisingly, anacondas sometimes cluster in a breeding ball that may have 2 to 12 males coiled around one female - and they may stay like this for up to 4 weeks! This breeding ball appears to be a slow-motion wrestling match among the males for an opportunity to mate. Does the strongest male win? Not necessarily! Females are usually larger and stronger and may choose which male (or males) they prefer. Courtship frequently takes place in water.

## A snake that gives birth

Like all boas, anacondas do not lay eggs; instead, they give birth to live young. The young are attached to a yolk sac and surrounded by a clear membrane, not a shell, as they develop in their mother’s body. This ensures they are kept at a fairly constant temperature and are protected from predators.

When the young are ready to be born, they are pushed out an opening called the cloaca. They are still surrounded by the protective membrane and must break it open. Then they are on their own to start protecting themselves (usually by hiding at first) and to find food. The newborn anacondas are smaller versions of the adults and instinctively know how to survive on their own.