It’s a little astounding that I haven’t written about anacondas yet. I tend to gravitate towards extremes when I’m picking animals to write about, so although I’ve written about the world’s smallest snake, the Barbados thread snake, I have yet to write about the biggest. 

Where you can find green anacondas, mainly in the Amazon and Orinoco river basins. Image by Gossipguy, CC BY-SA 4.0, via Wikimedia Commons

Of course, ‘biggest’ is not the clearest of terms. Although green anacondas are the world’s heaviest snake, they are not quite the longest. That honour goes to the reticulated python, a snake I will add to my long list of future blog posts. But being the best at something is nothing to sneeze at, and anacondas are very good at being large. There’s a lot of controversy surrounding green anaconda measurements, but the largest confirmed anaconda was a whopping 5.21 m long and weighed 97.5 kg. Female anacondas are larger than males, averaging lengths of 4.6 m, while males only average a paltry three meters. 

Green anacondas aren’t the flashiest of snakes, with fairly drab olive-green colouring covered in black splotches. They do have orange stripes on the side of their heads, which makes them look pretty cool from the front. The green anaconda’s fairly plain colouring makes sense when you consider where they live: they are found in swamps, marshes, and lazy streams. In other words, they like to hang out in muddy waters with lots of vegetation, which matches their colouration perfectly.

These muddy green snakes aren’t particularly stunning, but they are impressive looking. Image by Dave Lonsdale, CC BY 2.0, via Wikimedia Commons

Some anacondas live in savannah areas, where seasonal changes mean the snakes must either migrate to find water, or hide in the mud until the rainy season. Snakes that do bury themselves enter a dormant period, conserving energy until water returns. 

Anacondas spend most of their time in water, waiting for prey to come to them. Their eyes and nostrils are positioned on top of their heads, so they can sit stealthily, almost totally under the water until some poor animal comes by to have a drink. Imagine you’re a deer. You’re prancing along. You get thirsty. You spot a little brook. You put your little deer lips down to the cool, clear water. And BAM! An anaconda is coiled around you, squeezing the life out of your body as the blood flow is cut off to your vital organs. 

Anacondas do feed on deer, and pretty much anything else they can get, including fish, birds, and reptiles. They are capable of feeding on prey up to 50% of their own body mass, though anacondas usually feed on smaller prey. Tapirs, capybaras, caimans, peccaries and more have all been victims of anacondas. 

Imagine coming across this snake at night – it’d be nearly impossible to spot in the vegetation. Image by Fernando Flores, CC BY-SA 3.0, via Wikimedia Commons

Reproduction in green anacondas is quite the party. The mating season occurs from April to May, and it’s up to male anacondas to go in search of a mate. Unfortunately for them, they’re not the only males looking for some love. Male anacondas that find the same female compete by coiling around the female and attempting to be the first to mate with her. These ‘breeding balls’ can last for two to four weeks, which sounds pretty awful for the female. 

Six to seven months after mating, the female anaconda gives birth to live young. Litter size averages 20-40 baby snakes, but up to 100 can be born in a litter. That’s a lot of little snakes! The mother does not provide any care for her young (who would want to raise 100 children!?), and many die before adulthood due to their small size. Rarely, a female anaconda can give birth without a male, in a process known as parthenogenesis. 

Though anacondas are huge and are capable of taking down large prey, they don’t really eat people (despite what the movies say). Of course, I really don’t think I’d like to stumble across a five-meter long snake lurking in a swamp, but thankfully I live pretty far away from the Amazon. And to be fair to anacondas, I don’t think I’d like to stumble across any large animal lurking in a swamp.

Cover image by Daniel10ortegaven, CC BY-SA 3.0, via Wikimedia Commons, cropped to fit