Santorini, Greece (CBS Local) – The Greek island of Santorini is known for its stunning views, steeps hills, and tradition of using donkeys as the main form of transportation. While most tourists love traveling the island on a donkey, activists are now saying visitors from the U.S. and Europe are too fat to sit on the animals.

Activists with “Help the Santorini Donkeys” told multiple news outlets in the United Kingdom that overweight tourists are crippling donkeys, who are developing spine and legs problems from carrying so many people.

“Locals have even started breeding their donkeys with stronger mules so it is easier for them to carry fatter tourists,” according to a report in The Mirror.

“It’s recommended that animals should carry no more than 20 percent of their own body weight,” a spokesman for Help the Santorini Donkeys told the Daily Mail. “The obese and overweight tourists, combined with the lack of shade and water as well as the sheer heat and 568 cobbled steps, is what is causing such a problem.”

A peaceful protest against the overworking of the donkeys turned violent when local tour guides confronted the activists on July 27.

After the incident, Santorini officials reportedly issued a statement saying they met with the animal rights group and donkeys owners to agree on new measures to care for the animals.

Donkeys in Santorini will reportedly have their hours of work monitored, more shade provided, and more food and water given during breaks. According to The Kansas City Star, Greek officials did not address the issue of “fatter tourists” in the new safety measures for donkeys.