In general, scientists have a clear idea of what snakes eat, according to Brian Maritz, Senior Lecturer in the Department of Biodiversity and Conservation Biology at the University of the Western Cape. For example, one rule of thumb is that there are no vegetarian snakes, since no snake species eats any plant material and every snake on the planet is a predator of other animals.
What other animals they eat, however, varies wildly depending on species, geography, time of year, and more. “In terms of the details of what individual species eat, we have relatively limited information for most species,” says Maritz.
Some snakes prefer to eat amphibians, such as frogs, and arthropods, such as spiders, or anything from ants and termite eggs to soft-bodied earthworms. Others favor mammals, such as mice, all the way up to antelopes – think giant snakes like pythons and anacondas and how they can eat huge things, including humans. And then some like to eat birds.
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Yes, some snakes like to eat birds
Given how varied a snake’s diet is, of over 4,000 species of snakes worldwide, there are several snakes that like to make birds a staple of their diet. Although there are species that feed primarily on birds, no snake eats only bird food, according to Maritz, because true specialization on one prey item is rare.
“I guess the biggest indicator of whether you can eat birds is body size,” says Maritz.
In fact, consumption of adult birds is relatively rare. There are some species that like the taste of adult birds, but these are usually larger-bodied snakes – such as king snakes — supposedly because of the physical limitations of swallowing a bird.
“Keep in mind that snakes swallow their prey whole,” says Maritz. “Birds have wings that stick out in weird ways that are problematic. They’re relatively chubby, stocky animals, they’ve got all these extra fluffy feathers all over them that don’t provide any nutritional value.
Most snake species prefer to forage for chicks or bird eggs instead, as they are easier to catch and eat. Not only are they smaller and easier to swallow whole, they’re also less likely to backfire, especially eggs.
Snakes also sometimes change their diet as they age: when they’re young, they start out eating amphibians and reptiles, then as they get older, there’s an inclusion of more endothermic prey like mammals and birds.
How snakes kill a bird
Eating birds is common for both non-venomous and venomous snakes, and various different types of poisons can be effective in immobilizing a bird: be it cocktails of toxins that deal with the body’s circulatory system or the body’s nervous system, for example.
What’s more, nibbling on bird bites is something that both tree-climbing and ground-dwelling snakes seem to enjoy. Birds occupy both environments, making it convenient for different snake species that like to hunt in different ways.
“It’s not clear-cut one or the other, we tend to think of it as a continuum,” says Maritz.
Some species are more active foragers and search the environment and try to find traces of their prey in order to grab it – whip snakes, garter snakesand some species rats snakes i love playing this hunting game. They can actively attack nests both on the ground and in trees, for example. Other species of snakes may sit still and wait for prey to pass by, then reach out and grab them. Such is the case with some of the Asiatic vipers, or the American rattlesnakes, or the pythons and bois.
The tale of the common egg-eater
“However, there are species that feed exclusively on birds eggsMaritz says. He thinks about an African Dasypeltis species, also known as the common egg-eater. “Dasypeltis are these just outrageous snakes.”
Here’s how they do it. First they move around the landscape, find a nest and grab an egg. They then swallow it down their throats without breaking it because they have essentially toothless jaws and press it down with their throats against several protrusions on the back of the spine, which causes the egg to burst. Finally, they drink the contents and regurgitate the eggshells.
“It’s a really, really cool system,” says Maritz, a system that has also been studied in the Indian egg-eating snake (Elachistodon westermanni), which is ecologically similar. Various rat snakes are also known to eat a bunch of bird eggs as well bull snakeskingsnakes and eastern racers.
The Tale of the Spider Horned Viper
The spider-tailed horned viper (Pseudocerastes urarachnoides) is a species endemic to the Middle East, namely parts of Iran and Iraq. According to Maritz, it is not particularly well known, as it was first officially described only in 2006.
But it’s his sheer predatory system that makes birds shudder. These vipers do what’s known as “caudal luring,” which is basically when snakes mimic something interesting about their prey by moving their tails. For example, the spider-tailed viper uses its spider-like tail to lure birds, who in turn fly in to attack what appears to be a tasty snack and are caught in a nasty surprise.
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Tasty birds in the desert
In South Africa’s Kalahari Desert, with its mostly open, dry landscape, large trees are often home to giant common bird nests. Weaverbirds are also known as ‘social weavers’ because their nests – which have over hundreds of chambers – act as a breeding ground to which they return each year and can host colonies of 600 to 700 birds.
Cape cobras in the Kalahari desert climb these treesthey maintain grip on their bodies and then use their sense of smell to track down which chambers contain the eggs and chicks, mainly raiding their nests when it’s breeding season.
“They use these birds as a really important resource as part of their diet when they’re available. And importantly, they are only available after a really heavy rain,” Maritz says. “For weavers, snakes are certainly the main determinant of whether or not these birds successfully breed.”