Two young female tigers settle in at Dublin zoo

Gone are the days when the animals at Dublin zoo used to pad about lazily on concrete plains. Today they're subjected to personal "enrichment" in the most natural of habitats.

So says Ciarán McMahon, the carnivore and primate keeper at Dublin zoo, which officially unveiled its latest additions yesterday - a pair of young female Amur tigers donated from Edinburgh zoo.

The two-year-olds were put through their paces with long-term resident male Turlough to coincide with the opening of a new exhibition space, marking the end of a five-year redevelopment of the zoo.

Gorging on pigs' heads that had been frozen into a block of ice, the feline trio were getting not just nutrition but exercise, Mr McMahon explained. "The idea is that they have to work for their food. It takes a couple of hours to get the meat out of the ice, and we only feed them every three days. So they have to bury their meat and come back to it when they need it.

"It's all about enrichment. We must enrich their lives every single day."

Visitors are given a close-up view through a new glass-fronted viewing bay, which has been cut into the enclosure.

More than 1,000 small trees of the species found in the tigers' wild habitat in northern Russia are in place, along with an artificial stream, rock work, and a fallen tree which doubles up as a gymnastics beam.

"Tigers work on height dominance. They rule their environment - we don't," said Mr McMahon. "From the top of the hill here, they can see all over the zoo."

Just 400 Amur tigers can be found in the wild today.