![Nanook, a one-year-old polar bear plays with its birthday presents at a zoo in Gelsenkirchen, Germany on December 4, 2018. The female polar bear was born on December 4, 2017. (Photo/Agencies)](http://www.ecns.cn/hd/2018/12/05/cc84dd50e785429781068e216b6b8329.jpg)
Nanook, a one-year-old polar bear plays with its birthday presents at a zoo in Gelsenkirchen, Germany on December 4, 2018. The female polar bear was born on December 4, 2017. (Photo/Agencies)
![Nanook, a one-year-old polar bear plays with its birthday presents at a zoo in Gelsenkirchen, Germany on December 4, 2018. The female polar bear was born on December 4, 2017. (Photo/Agencies)](http://www.ecns.cn/hd/2018/12/05/a72a68fe944b4661a3f18b569031ffac.jpg)
Nanook, a one-year-old polar bear plays with its birthday presents at a zoo in Gelsenkirchen, Germany on December 4, 2018. The female polar bear was born on December 4, 2017. (Photo/Agencies)
![Nanook, a one-year-old polar bear plays with its birthday presents at a zoo in Gelsenkirchen, Germany on December 4, 2018. The female polar bear was born on December 4, 2017. (Photo/Agencies)](http://www.ecns.cn/hd/2018/12/05/e0465fb04a8b4bd5a6e5f0e3bead20ed.jpg)
Nanook, a one-year-old polar bear plays with its birthday presents at a zoo in Gelsenkirchen, Germany on December 4, 2018. The female polar bear was born on December 4, 2017. (Photo/Agencies)