Born in Antarctica, the penguins at Tokyo's Ueno Zoo may be home sick, missing the days when they were able to freely walk long distances on the ice. That had been the concern of zoo officials, who say that's why they have started allowing the King Penguins to walk once a week inside the zoo during the winter time to "make their living environment closer to the one they had". During their 30-minute march, the penguins waddle through the zoo and walk about 300 metres, charming children and adults alike. And they appear to like people's attention. The zoo says that since the penguins have started this regular exercise, they seem to be less stressed and even become fidgety when their march hours approach. Nine-year-old elementary school student Chin Isseki said while this wasn't the first time he'd seen penguins, it was indeed a new experience to see them take their weekly walk. "This was not the first time I saw penguins, but watching them march like this was certainly new to me," he said Naomi Komura watched the march with her young son. "It was co cute to watch them coming waddling all together," said the 31-year-old mother. The King Penguin is the second largest species of penguin at about 90 cm (3 feet) tall and weighing 11 to 15 kg (24 to 33 lb), second only to the Emperor Penguin. The King Penguin population is estimated to be around four million.