A freezing Hanoi has welcomed the 2019 New Year.
Monkeys crawl into a wooden box and huddle together to ward off the cold.
Pham Dinh Manh, head of the Hanoi Zoo Company Limited’s technical department, said on days when the temperature falls below 10 degrees Celsius, animals accustomed to tropical climate like hippos, oryxes and African lions are prone to shock. "We have to work in 24-hour shifts to adjust the heater thermostat and monitor the animals’ health."
The elephants’ barn is covered with canvas and has six high-capacity air-conditioners turned on to keep warm. The pachyderms’ diet is supplemented with sugarcane, nutritional bran and vitamins.
According to Nguyen Ngoc Anh, who takes care of the elephants, the animals tend to feel bored and irritable when kept indoors, and so he often has to visit and comfort them.
Each Indochinese tiger cage is equipped with an oil heater. Visitors are not allowed near them.
A worker checks a room heater in front of a lion's cage. Trum, the male lion, was born at Thu Le zoo almost a year ago.
A herd of spotted deer take refuge a fire. The creature is close to extinction in Vietnam.
A worker collects straws to line the floors of cages for warmth. Thu Le has stocked two warehouses with straw and dry grass to prepare for winter.
The African oryx lives in semidesert conditions. On cold days zoo staff light fires and put straw on the floors for the animals to sleep.
An Asiatic Black bear stands close to a heater as the temperature falls to 11 degrees Celsius. The animal is endemic to Vietnam, where it lives in many forests. Poaching and capturing them for their gall has meant only a few remain in the wild.
Mud pools of hippos are regularly supplemented with warm water. The hippopotamus resides mainly in the swamps and mangrove forests of West Africa.