African elephants Brittany and Ruth, both 38 years old, are seen at Milwaukee Zoo, Wisconsin, the United States, July 30, 2019. Milwaukee Zoo looks to be the new home for some elephants no longer appearing in circuses. (Photo by Joel Lerner/Xinhua)

The 38-year-old African elephant Brittany pushes a log at Milwaukee Zoo, Wisconsin, the United States, July 30, 2019. Milwaukee Zoo looks to be the new home for some elephants no longer appearing in circuses. (Photo by Joel Lerner/Xinhua)

The 38-year-old African elephant Brittany pushes a log at Milwaukee Zoo, Wisconsin, the United States, July 30, 2019. Milwaukee Zoo looks to be the new home for some elephants no longer appearing in circuses. (Photo by Joel Lerner/Xinhua)

The 38-year-old African elephant Brittany pushes a log at Milwaukee Zoo, Wisconsin, the United States, July 30, 2019. Milwaukee Zoo looks to be the new home for some elephants no longer appearing in circuses. (Photo by Joel Lerner/Xinhua)

The 38-year-old African elephant Brittany eats some tree bark at Milwaukee Zoo, Wisconsin, the United States, July 30, 2019. Milwaukee Zoo looks to be the new home for some elephants no longer appearing in circuses. (Photo by Joel Lerner/Xinhua)

The 38-year-old African elephant Ruth wanders at Milwaukee Zoo, Wisconsin, the United States, July 30, 2019. Milwaukee Zoo looks to be the new home for some elephants no longer appearing in circuses. (Photo by Joel Lerner/Xinhua)