Bactrian camels enjoy their breakfast served in a super-sized stocking during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
A gorilla enjoys the treats in a giant advent calendar during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
Lions enjoy 'Christmas pudding', a giant ball scented with classic yuletide spices, during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
A gorilla enjoys the treats in a giant advent calendar during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
A gorilla enjoys the treats in a giant advent calendar during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
A lion enjoys 'Christmas pudding', a giant ball scented with classic yuletide spices, during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
A gorilla enjoys the treats in a giant advent calendar during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
A gorilla enjoys the treats in a giant advent calendar during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
Bactrian camels enjoy their breakfast served in a super-sized stocking during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
A lion enjoys 'Christmas pudding', a giant ball scented with classic yuletide spices, during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
A lion enjoys 'Christmas pudding',a giant ball scented with classic yuletide spices, during an 'Animal Adventures this Christmas' photocall at Zoological Society of London (ZSL) London Zoo, in London, Britain, on Dec. 20, 2018. Zookeepers of the ZSL London Zoo prepared some seasonal surprises for the Zoo's residents to enjoy on Thursday. (Xinhua/Isabel Infantes)
