PeerJ retracts study that secretly observed tourists’ reactions to snakes

The journal PeerJ has retracted a study that attempted to capture tourists’ “authentic responses” to venomous snakes by putting plastic models and dead vipers around popular hiking destinations and secretly watching how people reacted to the encounters. Study author Angel Valentinov Dyugmedzhiev of the Bulgarian Academy of Sciences assessed their reactions from a few meters away and never interacted with any of the participants so as to avoid “direct interference in the experimental setup,” he wrote in the paper, published June 23. When tourists discussed the snakes among themselves, he recorded whether they correctly identified the species and whether they realized the viper was either dead or a model. The study found most tourists didn’t spot the vipers, and only a small number of them showed strong fear toward them. The paper stated the Institute of Biodiversity and Ecosystem Research Ethics Committee had approved the methodology. The journal put an expression of concern on the paper on Aug. 4 after having been “made aware that there are concerns regarding the ethical oversight of this study.” Following an investigation, the journal determined “the ethical approval was not, in fact, in compliance with PeerJ requirements” and retracted the study on August 21. The retraction notice does not specify the nature of the ethical concerns. Mark Robinson, a senior communications manager at Taylor & Francis, which acquired PeerJ in 2024, said: “our position is set out in the Retraction Notice, and we do not have anything further to add.” Dyugmedzhiev did not respond to requests for comment, nor did Javier Manjarrez, an ecologist at Universidad Nacional Autónoma de Mexico, the academic editor listed on the paper. The notice does not state whether the author objected to the retraction. This isn’t the first snake study with unorthodox methodology to be retracted over ethical concerns. In 2025, Scientific Reports retracted a study that involved softly stepping on venomous snakes to see when they would bite. Last week the work won an Ig Nobel Prize. The Retraction Watch database lists eight retractions from PeerJ since 2016. The for-profit journal officially launched in 2012. Like Retraction Watch? You can make a tax-deductible contribution to support our work, follow us on X or Bluesky, like us on Facebook, follow us on LinkedIn, add us to your RSS reader, or subscribe to our daily digest. If you find a retraction that’s not in our database, you can let us know here. For comments or feedback, email us at [email protected].