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New Scientific Analysis of Dolphin Slaughter Reveals Shocking Levels of Cruelty


FROM: Hunter College

Corresponding author: Diana Reiss, Professor, Department of Psychology, Hunter College, City University of New York, 646-775-5059/ 212-650-3432 or /

Whale and Dolphin Conservation/US: Courtney Vail, 480-747-5015 or

Newly-released, independent analysis of killing methods used by fishermen involved in the dolphin drive hunts in Taiji, Japan has revealed disturbing levels of physical trauma and extreme cruelty that fall below international levels of animal welfare.

Recent undercover video footage documents what Japanese officials claim is an improved method for killing dolphins and whales in the hunts. The shocking video shows a fisherman repeatedly ramming a metal rod into the base of a dolphin’s head, and how the wound, caused by the insertion of the metal rod behind the dolphin’s blowhole, is then plugged with a wooden dowel to prevent unsightly bleeding into the water.

Lead author Dr. Andy Butterworth, a veterinarian from the University of Bristol (UK), who is internationally known for his work in animal welfare assessment, animal use and abuse issues, Dr. Diana Reiss, a Hunter College Professor and internationally known expert in dolphin behavior and cognition and their co-authors criticize this killing method in a paper that has recently been published in the Journal of Applied Animal Welfare Science (JAAWS).

Click here for a PDF version of the paper. 
Click here for a link to the video footage.
PLEASE NOTE: Video footage is not suitable for children — or many adults, for that matter.

By comparing the video data obtained directly from the hunts (which occur annually from September to April) with data published in Japan, the analysis refutes claims that the new killing method results in a ‘quick death’ and instead examines the physical and behavioral impacts of these extremely inhumane procedures.

Dr. Butterworth, and his co-authors conclude that this method does not lead to a quick and painless death, contrary to reports from Japanese researchers. Instead, this brutal method leads to significant hemorrhaging and likely paralysis, and results in a slow death through trauma and gradual blood loss.

“Our analysis shows that this killing method does not conform to the recognized requirement for ‘immediate insensibility’ and would not be tolerated or permitted in any regulated slaughterhouse process in the developed world,” Butterworth concludes. 

Therefore, the methods currently utilized in the drive hunts do not guarantee a swift and humane death, may prolong suffering, and do not conform to internationally-recognized animal welfare requirements. 

The dolphin drive hunts in Japan involve the herding of dolphins at sea and driving and corralling them into the confines of the cove in Taiji. Here, behind curtains drawn across the cove, they are slaughtered for meat, or kept alive for sale to some marine parks across the globe. The scientific analysis presented in this paper underscores the fact that the killing methods used in the drive hunts are unacceptable by any country’s standards, including even Japan’s own humane slaughter guidelines.

“The killing of dolphins by any method is unacceptable, but our research into the true nature of the particular killing methods utilized in the drive hunts in Taiji has confirmed our worst fears. This analysis verifies the unspeakable cruelty taking place behind the tarpaulins that are used by the fishermen to try to shield the slaughter each season,” said Courtney Vail, Whale and Dolphin Conservation (WDC) biologist and co-author. 

“It is a sad irony that in trying to find an improved killing method, but perhaps also to reduce the unsightly flow of blood into the water, the hunters have developed a new technique which likely exacerbates the suffering for the dolphins killed in these appalling hunts,” said WDC senior biologist and co-author, Philippa Brakes.

“The inhumane killing methods used in the dolphin drives are a blatant violation of any reasonable animal welfare standards and are indefensible given our scientific knowledge of dolphins which has demonstrated their sophisticated cognitive abilities including self and social awareness, cultural richness, and their capacity to experience pain and suffering,” said Dr. Diana Reiss, the corresponding author on the paper.

Click here for further coverage and a Q&A session with Dr. Reiss by the New York Times. 

Conservation, Research