A sudden slide in temperature has prompted zoo authorities to introduce a slew of measures to keep the animals cosy.

Sanjay Gandhi Biological Park authorities have arranged blankets, straw and hay beds and vitamin supplements for the animals with the temperature hovering around 10ºC on Sunday. Heaters are being kept near enclosures and night houses of various animals. Sources in the zoo said special care was being taken for the animals that are either ageing or are expecting.

Zoo veterinary doctor Ajit Kumar said: “Winter arrives usually in the first week of December. But the nip in the air could be felt from the last week of November. This year, the fluctuation between day and night temperatures has been unpredictable. The temperature soared during the first week in December. But there has been a sudden dip in the past two and three days. The minimum temperature is being recorded at less than 10°C over the past two days. The temperature inside the zoo is normally three to four degrees less than the city’s.”

The timing for a visit to the zoo has been changed. At present, the zoo closes at 5pm, an hour earlier than in summer. The time the zoo opens is unchanged — 8am. Ventilators at the night houses are being covered with straw to keep out the cold air. Though most snakes have gone into hibernation, blankets have been placed on the floor and 200W bulbs are being used inside the snake house from the first week of November.

The authorities have also bought 25 room heaters to keep the enclosures and the night houses warm. The heaters have been placed in the night houses of all animals, including tigers, lions and leopards. The night houses have been provided with beds made of straw and hay. Apart from the regular diet, each big cat is being fed with 2kg of chicken and a kilo of liver for breakfast.

Special care and diet are being arranged for Sita, the ageing 18-year-old tigress. “The average life of a tiger is 18. Sita has been, so far, the longest living big cat at the Patna zoo. We give her chicken soup, fresh liver, boneless beef and egg, in addition to the regular diet,” said Dr Ajit.

The six sloth bears and four Himalayan bears have been provided with room heaters. Their night houses, too, have been provided with straw padding. Other older animals in the zoo are being provided with food supplements, warmer beds and preventive antibiotics.

On the winter-special diet for the animals, Dr Ajit said: “All carnivores are being given 2kg of extra meat. The daily dose of beef for each big cat has been increased.”