2 days ago
Video Shows Snake Trying To Eat Prey 10 Times Her Size
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.
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A snake in Denmark has been spotted attempting to consume an oversized hare that's 10 times larger than itself.
The chance observation of an adult female common European adder killing and intending to swallow a much larger prey—a European young hare—was captured in a series of videos by Klaus Birch, the co-author of a study on the encounter published in the journal Herpetozoa.
The moment unfolded on the island of Læsø in the Kattegat region of northern Denmark—near a dirt road in open grassland around 32 feet from a sandy beach—back in August 2022.
The snake appeared to be in a low nutritional status, likely after having given birth recently, the study said.
"The adder under these circumstances might have benefited from a large prey to gain maximum energy after likely having given birth," the researchers said.
Stills from videos showing a female Vipera berus snake biting and pulling the hare's front leg (pictured left) and examining and biting the head (pictured right).
Stills from videos showing a female Vipera berus snake biting and pulling the hare's front leg (pictured left) and examining and biting the head (pictured right).
Klaus Birch
Birch arrived at the scene and found the adder examining the young hare and biting its left hind leg. "The hare was lying on the ground moving its four legs jerkily and head with difficulty and was unable to stand up," the researchers wrote in the study. The adder was startled by Birch's presence and escaped into the grass nearby.
Within seconds, the adder returned to the hare and continued examining it, especially the front legs and the head, before zipping away into the grass again.
However, around 20 seconds later, the snake returned to the scene and examined the hare "carefully and energetically," starting with its posterior parts, biting and moving the right hind leg, the study notes.
The snake then examined the anterior parts of the hare, biting and pulling a front leg, before also biting its head. "The hare was still breathing but moved less than before," the study said. Birch chased the snake away and took the hare to attempt to save its life, but it died after around 30 minutes.
While it is unknown whether the adder would have tried to swallow the hare had Birch not intervened, the researchers believe it is "likely" that the snake "would have abandoned its excessively large prey after careful examination."
The study noted that it is unusual for snakes to regularly attack vastly oversized prey items that are clearly impossible to swallow.
However, cases like this have been reported in previous research, such as an earlier observation of snakes that overestimated their abilities to swallow young rabbits and died while trying to do so.
A previous study also noted a case of a snake that was found dead after it had just swallowed a large field vole. "The mass of the prey was 26g and the snake's mass after the prey had been removed was 28g. The adder had therefore consumed a meal equivalent to 92.9 percent of its mass," the team noted.
The researchers concluded: "The above cases indicate that snakes killing and subsequently abandoning oversized prey items may well be an underreported phenomenon."
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Reference
Bringsøe, H., Jablonski, D., & Birch, K. (2025). Overly optimistic adder, Vipera berus (Linnaeus, 1758), killing and intending to swallow an oversized young hare, Lepus europaeus Pallas, 1778. Herpetozoa, 38, 155–159.
Bull, D. (2016). Vipera berus (northern viper): Morphometrics of feeding on a common field vole. Herpetological Bulletin, 136, 33–34.
