MARWELL Zoo's gibbons were on their best behaviour as they received a royal visitor to officially open their new £600,000 enclosure.

HRH The Princess Royal gave the new 5,000 square metre South East Asia exhibit, Life in the Trees, her seal of approval.

Members of the public and visitors to the park, near Winchester, have donated £417,000 towards the cost of the new home of Marwell's family of siamang gibbons, as well as several other species.

The enclosure is designed to replicate the gibbons' natural habitat and includes a large play area, trees to swing from and a clearing to relax in.

The siamangs, like all apes, are threatened in the wild due to the deforestation of their natural habitat.

Yesterday, the Princess Royal was taken on a guided tour of the new home - the fourth exhibit she has opened at the park - and met Marwell staff.

Earlier the princess had dropped in to Southampton Boat Show, where she was greeted by Geoff Holt, who earlier ths month became the first disabled person to sail round Britain single handedly.

She then met up with Southampton round-the-world sailor Mike Golding to officially name his new raceboat Ecover, as well as meeting the members of Team Origin, the new British challenge for the 2009 America's Cup, which includes Hampshire sailors Ben Ainslie, Rob Greenhalgh and David Carr.

During her trip to the south the Princess Royal opened the Institute of Developmental Sciences, next to Southampton General Hospital.

Researchers at the new institute will look at how people's health can be determined by events that happen in early life.