While animals including anteaters, gorillas and orang-utans prefer have shown a natural preference for staying inside during the current glacial conditions, other animals need more intensive protection, according to Robert Zingg with Zoo Zurich.
Although the zoo's young male elephant would rather be outside, his time in the open has been limited because pachyderms are very sensitive to the cold, Zingg explained to Swiss daily Blick.
Elephants at Zoo Basel are also being keep indoors for long periods. "Elephants have very thin ears. If they stay too long outside they can get frozen earlobes," zoo spokesperson Tanja Dietrich said.
Back in Zurich, marmosets are not being allowed out at all. "Because they are so small, they would quickly cool down," Zingg said.
Meanwhile in Basel, the water in the moat around the lion's enclosure has been emptied after it froze. On Monday, zoo staff had to break up the ice so that the lions could not simply across it.
Switzerland continues to shiver
While Monday started off well below freezing in Switzerland, conditions were even colder on Tuesday morning.
In Samedan in the canton of Graubünden, the temperature at 7.10am was -26.5C, according to SRF Meteo. In Zurich, the figure was -11.1C, Bern saw -10.9C and in Luzern it was -10.2C.
Maximum temperatures are expected to be below -5C in many places across Switzerland on Tuesday, according to MeteoNews.
Forecasters say the cold snap will reach a peak on the night of Tuesday to Wednesday with clear skies and a drop in winds meaning low-lying areas will experience temperatures between -12C and -15C.