Cannibalism in Snakes Is Not Uncommon — but Could be a Behavior That’s Tied to Evolution
In November 2025, researchers from the Universidade Federal de São Carlos in Brazil published a study in Biological examinations which examined more than 500 cases of snake species documented in the scientific literature as having eaten conspecifics or snakes of the same species. In total, scientists have recorded at least 207 species exhibiting cannibalism in 15 families, both in captivity and in the wild.
According to the study authors, cannibalism in snakes can be considered a predatory event, even though consuming a conspecific may seem like a counterproductive behavior. Some researchers thought this was a behavior triggered by stress in captivity, but it has been shown to occur in the wild.
Since then, the team wrote, various hypotheses have been proposed to explain cannibalistic behavior, such as a method of energy conservation, control of their clutch size, and adaptation when no other food is available. Cannibalistic behavior has been recorded in many groups of animals, including fish, birds, mammals and amphibians. But snakes are perhaps among the animals most frequently involved in cannibalism.
Learn more: Partially eaten remains reveal cannibalism is biggest threat to young Chesapeake Bay blue crabs
Do snakes evolve to become cannibals?
To reach their conclusions, the Brazilian team examined existing Portuguese and English scientific literature documenting recorded cannibalism in snake species, totaling 299 articles. The majority of these cases – 218 – were recorded in captivity, where confinement and movement restrictions, as well as lack of enrichment and proximity to other snakes, could play a major role.
Despite this, the researchers concluded that their work constitutes the most comprehensive study of cannibalism in snakes to date and found that the behavior is widespread in taxonomic and geographic terms. The team noted that snake cannibalism has been recorded on every continent where snakes live.
But does this mean snakes evolve to become cannibals, or do they simply practice cannibalistic behaviors? Kurt Schwenk, a herpetologist and evolutionary biologist who was not involved in the study, said that in many of these cases, and especially those recorded in custody, the cannibalism was just a matter of circumstances.
“Cannibalism is something that happens from time to time in snakes, mostly due to chance and opportunity,” Schwekn said. Discover. “In fact, calling it “cannibalism” is misleading because it is not a diet, strategy, or evolved specialization of any kind.
In other words, some snakes occasionally eat a conspecific not because they seek it out as a preferred prey type, but because the conspecific fits the general parameters of what the predatory snake species would otherwise have eaten. The possibility of eating another snake is purely coincidental.
When snakes exhibit cannibalistic behavior
Cannibalistic behavior is a relatively rare, although widespread, phenomenon in snakes that is more likely to occur in species that already have a tendency to eat other snakes, a concept known as ophiophagy. This is especially true for cobras. Cape cobras, a medium-sized snake found in South Africa, are known to eat other snake species, which can make up about a third of their diet. However, eating their conspecifics is even rarer, according to a 2018 study from Ecological Society of America.
“For them, it’s just another prey,” Schwenk said. Discover.
Cannibalistic behavior is more likely to occur in snake species with a generalist diet.
“They eat just about anything they can put in their mouth – they’re not picky eaters. As in more specialized ophiophagous species, they simply don’t avoid eating conspecifics. It’s just not relevant,” Schwenk said.
Another way to put the study results, Schwenk said, is that there is little evidence that snakes do not avoid cannibalism.
“In other words, any animal within the broad category of prey species consumed by a snake is fair game, conspecific or not. The relationship is not part of what they consider when evaluating potential prey as suitable or not,” he said. “Cannibalism is only beneficial to snakes in the sense that eating an occasional conspecific provides a meal, like any other. There is no evidence that it serves any other function or is some sort of evolved, adaptive strategy.”
Learn more: Why cannibalism is a common behavior in some animals
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