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Samantha Putterman
By Samantha Putterman May 17, 2019

Tumors on deer in viral photo were not caused by Monsanto’s Roundup

A disturbing photograph of a white-tailed deer covered with large tumors is back to making the rounds on social media.

Text above the photo says, "A deer became riddled with tumors from eating plants sprayed with Monsanto’s Roundup. It seems fairly common."

The post was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

The hairless protrusions are called Cutaneous fibromas, commonly referred to as deer warts, and are found in deer herds in a majority of U.S. states, according to a report by the Mississippi Department of Wildlife, Fisheries and Parks. As a result, the organization says, the warts are considered to exist in the entirety of the white-tailed deer range.

But such fibromas are not caused by "Monsanto’s Roundup," or any other herbicide.

The warts are caused by a viral infection believed to be transmitted through various biting insects. The viral agent may also be transmitted through direct contact with damaged skin. Once the virus enters the skin, the warts have been found to start forming within about seven weeks.

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The disease is also temporary, researchers say, and only lasts about two months before it starts to regress in most deer.

Kevin Hynes, a wildlife biologist at New York’s Department of Environmental Conservation, confirmed to PolitiFact by email that the protrusions in the photo are, in fact, fibromas.

"They are fairly common in N.Y. deer and are caused by a virus spread by biting insects or by direct contact; the virus does not infect humans or pets," Hynes wrote. "Fibromas are typically found in younger deer and they usually regress, dry up and fall off leaving no evidence they were ever there. Fibromas only cause problems for deer if they cover the eyes or are very large and/or numerous (as in your photo) and become secondarily infected with bacteria.’"

While their appearance may be grotesque, fibromas are not typically harmful to the deer, according to a 2011 publication by the USDA National Wildlife Research Center. However, the report says, deer with heavy tumor loads may suffer from "exhaustion and incapacitation due to tumors interfering with vision, respiration, food ingestion, and locomotion." Occasionally, researchers say, the fibromas can create a bacterial infection.

While our efforts to find the origin of this photograph using reverse-image searches were not conclusive, fact-checking website TruthOrFiction reported it first appeared in October 2017 on a Facebook page for hunters in a post that went over the actual cause for the growths.

Regardless of the origin, we do know that the picture shows a deer with growths that appear consistent with a condition commonly known as deer warts. The claim that such blemishes are caused by an herbicide is not true.

We rate this claim False.

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Says a deer became "riddled with tumors from eating plants sprayed with Monsanto’s Roundup."
Wednesday, May 8, 2019

Our Sources

Facebook post, May 8, 2019

Reverse image google search, May 15, 2019

Mississippi Department of Wildlife, Fisheries and Parks, Cutaneous Fibromas: A Closer Look, Accessed May 15, 2019

Oregon Department of Fish and Wildlife, Accessed May 15, 2019

USDA National Wildlife Research Center, Diseases and Parasites [of White-tailed Deer], 2011; Accessed May 15, 2019, White-tailed Deer Warts, Feb. 10, 2010

Science Direct, Purification and chemical analysis of Shope papilloma virus, Accessed May 15, 2019

TruthorFiction, The Case of the Monsanto Deer, Oct. 16, 2018

Email interview, Kevin Hynes wildlife biologist at New York’s Department of Environmental Conservation, May 16, 2019

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More by Samantha Putterman

Tumors on deer in viral photo were not caused by Monsanto’s Roundup

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