The green anaconda regurgitated his dinner straight into the Amazon swamp. (Reuters)

A video of a giant snake regurgitating an entire cow has gone viral, ratcheting up over 700,000 views on YouTube in just five days.

In the 90-second clip, a green anaconda with a large bump in its body is shown writhing on a shallow riverbed. It then opens its mouth and throws up the undigested carcass of the cow into the jungle swamp.

The sickening video was posted on the site by MrCocktail888 and was allegedly filmed in Brazil. Theories about what made ths snake sick vary; one observer said the reptile may have felt threatened and needed to regurgitate its food in order to make a quick escape if needed.

The South American snake is known to feast on a variety of animals from fish and birds to deer and even jaguars. The largest animal on record to have been consumed by a constrictor is a 59kg impala, eaten by a 4.8m long African rock python in 1955.

But not everyone is convinced that the regurgitated dinner was a cow. Some YouTube commentators said the creature might be a capybara, a large guinea-pig like rodent native to South America.

The green anaconda is a type of boa constrictor, a non-venomous snake that kills its prey by coiling round it and crushing it to death. The elastic ligaments of their jaws mean they can swallow any animal whole - so a cow would have been no problem to eat.

Pound for pound the green anaconda is the largest snake in the world. When fully grown, the reptile can measure more than 8.8 metres (27ft) and weigh more than 230kg, according to National Geographic.