Two new rare liligers go on show for the first time in Siberia

The pair first produced a liligress, a female cub, in 2012, and a year later Zita gave birth to three cubs - all female. 

Such offspring are known as 'hybrids', and Zita could not have been born in the wild. 

Deputy zoo director Olga Shilo denied the zoo is deliberately seeking to breed hybrids. She also said the cubs are healthy. 

She has said previously that there was genuine surprise when Zita was conceived and born. 

'Zita's parents have known each other since their early days, when they were quite young,' she said.

'The keepers saw that they overcame any natural enmity but we had no idea they would, or even could, mate. 

'Everyone was more than a little surprised when a flame of passion consumed these two very different childhood friends.'