People look at a white Siberian tiger at the Bioparco zoo in Rome, Italy, on May 29, 2020. The Bioparco zoo in Rome reopened on Friday with strict measures taken to curb the spread of COVID-19. (Photo by Alberto Lingria/Xinhua)

People wait to enter the Bioparco zoo in Rome, Italy, on May 29, 2020. The Bioparco zoo in Rome reopened on Friday with strict measures taken to curb the spread of COVID-19. (Photo by Alberto Lingria/Xinhua)

People look at a Persian leopard at the Bioparco zoo in Rome, Italy, on May 29, 2020. The Bioparco zoo in Rome reopened on Friday with strict measures taken to curb the spread of COVID-19. (Photo by Alberto Lingria/Xinhua)

Children look at a lion at the Bioparco zoo in Rome, Italy, on May 29, 2020. The Bioparco zoo in Rome reopened on Friday with strict measures taken to curb the spread of COVID-19. (Photo by Alberto Lingria/Xinhua)

An employee wearing a face mask feeds an otter at the Bioparco zoo in Rome, Italy, on May 29, 2020. The Bioparco zoo in Rome reopened on Friday with strict measures taken to curb the spread of COVID-19. (Photo by Alberto Lingria/Xinhua)

A girl looks at a lemur at the Bioparco zoo in Rome, Italy, on May 29, 2020. The Bioparco zoo in Rome reopened on Friday with strict measures taken to curb the spread of COVID-19. (Photo by Alberto Lingria/Xinhua)

A man holding a girl looks at an Asian elephant at the Bioparco zoo in Rome, Italy, on May 29, 2020. The Bioparco zoo in Rome reopened on Friday with strict measures taken to curb the spread of COVID-19. (Photo by Alberto Lingria/Xinhua)