The Scimitar Horned Oryx

The Scimitar Horned Oryx (Oryx dammah) is extinct across virtually all of its former range throughout Africa. It declined in numbers for a variety of reasons including overhunting, desertification, continuing war that exterminated it in Sudan, and overgrazing by livestock. In the 1960's it was classified as vulnerable and in 2003 pronounced extinct in the wild. Captive-bred oryx have been introduced into Israel and Tunisia but it appears the populations are unsustainable without captive breeding

The Socorro Dove

The Socorro dove (Zenaida graysoni) is unique to Socorro, one of the Revillagegido Islands off the west coast of Mexico. After 1957 its numbers declined drastically due to the loss of habitat. In the early 1970's the introduction of domestic cats soon killed the rest. Fortunately, the bird had been bred in captivity since the 1920's.

There are plans to reintroduce it to its island home once the habitat has been made safe again. DNA provided by the Zoological Society of London and held in the Frozen Ark should help to support the rescue.

Polynesian Tree Snails

Polynesian tree snails of the genus Partula that lived on the volcanic islands of the Pacific and included more than 100 species (of which 14 species are preserved in the Frozen Ark). They were first recorded in Captain Cook's voyage of 1774. These extraordinary snails provide a unique insight into the mechanisms of evolution and a base line against which to assess the catastrophic effects arising from the introduction of exotic predatory species.

They have become endangered as a result of efforts to control the huge, edible African land snail (Achatina fulica), introduced in 1967 as a delicacy. Within seven years, the African snail became such a serious pest that the government introduced a predatory snail, the rosy wolf snail (Euglandina rosea), to control them. The predatory snail tracks its prey chemically, sits on the shell of its quarry inserting its head into the mouth of the shell to suck out the contents. The predator found the small, thin-shelled Partula much easier prey than African land snails.

Since its introduction the snail has had a disastrous impact on the region's land snail fauna, with over 50 partulid species made extinct across the islands. An international breeding programme for these snails is currently maintaining populations of 22 species. The Frozen Ark, which has preserved the genetic material of 14 of these species, provides a unique opportunity to bank much of the current genetic line.

The Seychelles Frégate Beetle

The Seychelles Frégate Beetle (Polposipus herculeanus) is the world's largest tenebrionid beetle and today is only found on the small Seychelles Island of Frégate. Despite dedicated habitat management by the Island's owners, vulnerability to introduced predators and a fungal disease in the beetle's associated sandragon trees have resulted in the species becoming critically endangered.

A breeding and research programme was established at the Zoological Society of London in 1996. The initial population has now expanded to a full European Breeding Programme (under the auspices of the European Association of Zoos and Aquaria) and involves institutions in the UK, Netherlands, Poland and Latvia. Being able to preserve genetic representation of Frégate beetle generations closest to the original wild founder population in the Frozen Ark represents a major conservation safeguard for the Frégate beetle programme.

Frégate Island Snail

The breeding programme for the Frégate snail (Pachnodus fregatensis), illustrates how to provide emergency assistance to a threatened mollusc species. In 1995, rats became established on the Seychelles Island of Frégate where this species is endemic. The only captive population is a small group in London Zoo. Set up in plant propagator units with potting compost and the correct temperature and humidity, the result of rearing them have been spectacularly successful. From an original founding base of 20 animals, 400 individuals have been successfully raised.

The British Field Cricket

The British Field Cricket (Crylus campestris) was, by the beginning of the 1990's, reduced to a single surviving West Sussex colony numbering fewer than 100 individuals. This was due to loss of its grassland habitat. Over the last 14 years, a concerted conservation effort has been made by English Nature to establish new field cricket populations, through its Species Recovery Programme.

To this end, a long-term breeding and field release programme has been running at London Zoo's Invertebrate Conservation Unit to provide the large numbers (over 13,000 to date) of crickets needed to establish these new colonies. This programme has highlighted the fragility of specialised habitats.

The Yellow Seahorse

The Yellow Seahorse (Hippocampus kuda) is a small fish, 15 to 30 centimetres long. The female sea-horse lay its eggs in a pouch on the male's belly, and the male later gives birth to live young. Trade in traditional Chinese medicine, souvenirs and live aquarium fish have caused it to become endangered. Some aquaria are breeding them successfully, but holding their DNA will provide a back-up both for conservation efforts and for a better understanding of the biology of these unique creatures.