Last updated at 08:20

Pictures: UK zoos save species from extinction

The world's largest frogs, Britain's only native crayfish and Amur leopards are all being saved from being wiped out by the good work in UK zoos.
Almost all of Britain's white-clawed crayfish were killed after the introduction of the American signal crayfish which spread a deadly disease. UK zoos then set up safe breeding areas for the species.
Dr Andrew Marshall, who has been working on the programme said, "Without the valuable conservation and breeding work of many of our member zoos and aquariums, many 'at risk' species such as these may be lost to extinction forever."
The scimitar-horned Oryx used to be found in Tunisia, Morocco and Senegal in the north of Africa but are now all extinct in the wild. The blue-crowned laughing thrush, from China, and even a super rare tree - the Verdcourt's polyalthia - found in just three places in Tanzania, are also on the list.
Scimitar-horned Oryx
The mountain chicken frog is one of the biggest in the world, a deadly fungus nearly wiped out the entire population in the Caribbean. The surviving frogs were flown to the UK to be saved.
A list has been put together of the top endangered animals that are still surviving because of the conservation work done by UK zoos. Some of the species saved include this blue-eyed black lemur from Madagascar.
Rare Amur leopards are one of the big successes. There we only 45 left in the wild but special projects mean there are now 220 in zoos around the world.
Amur leopard
Polynesian tree snails and the potosi pupfish from Mexico are both extinct in the wild but are still alive in captivity because of special conservation programmes.