The zoo's resident brown bear Tony is getting treats of large ice cubes containing frozen fruit and meat.
His keeper hides the ice cream in a different place each time, but the 12-year-old bear keeps finding it.
This method is an attempt to mimic the animals' behaviour in the wild as much as possible.
"They should not be imprisoned, but provided with methods, ways to move, to look for food and seek variety," said the head of animal feeding Anita Tsvetanova.
Sofia's zoo is home to over 2,500 animals and the ice cream helps them cope with the Bulgarian heat.
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