Two tigers have been welcomed into a new home at London Zoo as part of a multi-million pound project to boost numbers of the critically endangered species.
Sumatran tigers Jae Jae and Melati have moved into a new £3.6 million enclosure called Tiger Territory which is being officially opened today by the Duke of Edinburgh.
It is hoped five-year-old male Jae Jae and four-year-old female Melati, whose grandfather Hari was London Zoo's last tiger cub, will breed after just 300 Sumatran tigers were recorded living in the wild.
Tony Cholerton, senior keeper at London Zoo, said: "Things aren't looking good for them in the wild. They suffer from poaching and deforestation so it's vitally important that we have a really good captive population."
The tigers had to be separated today after clashing in the enclosure but zoo staff reassured visitors it was normal mating behaviour.
Mr Cholerton added: "For tigers, it's all a bit rough and tumble. He will be seeing if she's in season and if she's not then she'll give him a couple of swipes to say 'go away, I'm not interested'. On a normal day we'd just leave them to it and things would calm down."
Tiger Territory is London Zoo's biggest investment in six years and has been designed by tiger keepers and conservationists from the Zoological Society of London.
The 27,000 sq ft (2,500 sq metre) enclosure is five times the size of the previous exhibit and includes a custom-built swimming pool.
As late as 1978, experts estimated the population of Sumatran tigers at 1,000. Today less than 400 exist, with just 300 left in the wild.
Deforestation and rampant poaching in the tigers' native homeland - the Indonesian island of Sumatra - have increased fears they could end up extinct like their Javan and Balinese relatives.