Anacondas are the heaviest, if not the largest, snakes in the world, with records of individuals stretching up to 12 m long and weighing up to 250 kg. They are semi-aquatic snakes living in the tropical habitat of South America and feeding on a range of species, including tapirs and caimans.
How many species of Anaconda are there?
There are four different species of anaconda: the green anaconda (the species that most people mean when they speak about Anacondas), the yellow anaconda, the dark-spotted anaconda and the Bolivian anaconda. These species can be distinguished from other species of boa snakes because they lack a particular bone called the supraorbital bone, which is usually found above the eye socket.
What does an anaconda look like?
Green anacondas have huge bodies covered in small olive-green scales, with smooth black ovals along their backs and yellowish stomachs. Compared to their huge bodies, anacondas have relatively small heads, with their eyes and nostrils positioned on top, an adaptation that allows them to lie hidden underwater. Only the top of their head shows above the surface. Green Anacondas also have a noticeable black stripe that runs from the eye to the jaw. Males are typically smaller than females and have claw-like spurs on their lower bodies, which they use to hold onto females during mating. Interestingly, these claws are believed to be the historical remnants of a hind limb! Like all snakes, anacondas have a forked tongue, which they use to locate prey and potential mates.
Where do anacondas live?
Anacondas are found throughout South America, where they spend the majority of their time in the shallow waters of open wetlands such as the Amazon River Basin, the Orinoco Basin in Columbia and the Llanos grasslands in Venezuela. There are instances of captive anacondas escaping and surviving further afield, with reports of native Florida species such as alligators and bobcats declining due to competition for food with non-native anacondas.
How do Anacondas move?
All snakes move by contracting the muscles between the scales on the undersides of their bodies, undulating themselves across land or through water. A large number of vertebrae linked flexibly together allow them to bend and coil in every direction.
When do anacondas breed?
Green Anacondas are polyandrous, which means a female will mate with several different males. Mating occurs during the dry season (March to May) and lasts for several weeks.
What does an anaconda eat?
Green anacondas are not venomous. They kill their prey by constriction, holding the animal in place with their sharp teeth (curved backwards to allow them a better grip) while squeezing their massive bodies around their victim until they suffocate. Their coils are powerful enough to kill animals the size of a horse or a fully-grown black caiman. And stretchy ligaments in their jaws mean they can open their mouths wide enough to swallow them.
Anacondas are opportunistic ambush predators. They lie hidden underwater (camouflaged by their dark colouring) until an animal approaches the water’s edge to drink, at which point they strike! As anacondas typically hunt near water, their prey often drowns before constriction is complete. Once the animal is dead, the anaconda will release its coils and ingest its prey headfirst (to reduce any obstruction caused by the limbs) and whole!
Green Anacondas are most active in the early evening and will eat anything they can swallow, including fish, reptiles such as turtles, amphibians, birds and mammals like capybaras and peccaries. Feeding on such large prey can be dangerous and occasionally leads to serious injuries. But, the danger may be worth the risk, as large anacondas can survive without eating for months after such a large meal.