PETA opposes all activities where animals are kept in captivity for profit, including those at zoos and aquariums, but these attractions will remain bookable. However, add-on attractions that are not in compliance with the new policy will not, TripAdvisor said. TripAdvisor's new policy also includes many exemptions, like feeding programs where visitors are under the supervision of zoo or wildlife officials, such as giraffe feeding at the San Diego Zoo, children's petting zoos with domestic animals and voluntourism programs like the ones at the Elephant Nature Park in Thailand, where contact with elephants is likely for visiting volunteers. Animal welfare groups are hoping these changes create a ripple effect throughout the travel booking industry. "TripAdvisor's competitors and others within the travel industry will take note of this, and we hope and expect that many other companies will follow," Ms. Shaw of PETA said.