Photo/Illutration A black cow painted to resemble a zebra was found to attract fewer blood-sucking insects. (Captured from the research paper by Tomoki Kojima’s team)

A Japanese research team's experiment involving disguising a cow as a zebra to fend off bloodthirsty insects received the 2025 Ig Nobel Prize's biology category on Sept. 18, making this the 19th consecutive year a team from Japan has won. 

The parody of the Nobel Prize honors research that is as thought-provoking as it makes people laugh. It is organized by the Annals of Improbable Research magazine themed around humorous scientific topics. 

“We’re deeply honored to receive this award. I still can’t believe that we really won,” said Tomoki Kojima.

Now a fixed-term researcher at the National Agriculture and Food Research Organization, Kojima led the study when he worked for a department supporting livestock farmers at the Aichi Agricultural Research Center.

The study came to be after he learned that livestock farmers were suffering from problems derived from bugs feasting on their charges.

Previous studies have shown that blood-suckers such as horseflies or stable flies are harmful to livestock and can affect cows' behavior. 

For example, not only can they spread bovine leukosis and other diseases, but the pain and itchiness of the bites may snowball into stress that manifests into stunted growth and producing less milk.

Three black cows were chosen as the canvas for the experiment after Kojima became aware of the theory that zebras' patterning deters hungry insects.

One cow was painted with white stripes to mimic a zebra's, another was given black stripes and the third was unadorned.

After totaling the number of blood-sucking insects seen in photos taken of each cow from the right, researchers found the white-striped bovine had half as many on it as the other two.

That cow also exhibited fewer behaviors typical of repelling insects, such as shaking its head or swishing its tail.

The results indicated that painting cows and other livestock to look like zebras is an actual viable alternative to insecticides, representing a potential new method of pest control beneficial to both the environment and human health.

“To spread use of this method, it is necessary to develop new, easy ways to paint livestock with zebra stripes that last a long time,” Kojima said.

The research paper can be read at: (https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0223447)

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