The last burcardo

The Pyrenean ibex was one of four subspecies of the Iberian ibex. The first to become extinct was the Portuguese ibex (Capra pyrenaica lusitanica) in 1892. The Pyrenean ibex was the second, with the last individual, a female called Celia, found dead in 2000.

In the Middle Ages, Pyrenean ibex were very abundant in the Pyrenees region, but decreased rapidly in the 19th and 20th centuries due to hunting pressure. In the second half of the 20th century, only a small population survived in the Ordesa National Park situated in the Spanish Central Pyrenees.

Competition with domestic and wild ungulates also contributed to the extinction of the Pyrenean ibex. Much of its range was shared with sheep, domestic goats, cattle, and horses, especially in summer when it was in the high mountain pastures. This led to interspecific competition and overgrazing, which particularly affected the ibex in dry years. In addition, the introduction of non-native wild ungulate species in areas occupied by the ibex (e.g. fallow deer and mouflon in the Sierras de Cazorla, Segura y Las Villas Natural Park) increased the grazing pressure, as well as the risk of transmission of both native and exotic diseases.

The last natural Pyrenean ibex, a female named Celia, was found dead on January 6, 2000. Although her cause of death is known (she was killed by a fallen tree), the reason for the extinction of the subspecies as a whole is a mystery. Some hypotheses include the inability to compete with other species for food, infections and diseases, and poaching.

The Pyrenean ibex became the first taxon ever to become "unextinct" on July 30, 2003, when a cloned female ibex was born alive and survived for several minutes, before dying from lung defects.

The cloning project.

The biotechnology company Advanced Cell Technology, Inc. announced on October 8, 2000, that the Spanish government had agreed to their offer to use nuclear transfer cloning technology in collaboration with other scientific partners to clone the Pyrenean ibex from the tissue that was taken in 1999. Celia, the last ibex, was captured in Ordesa y Monte Perdido National Park in Huesca, Spain; skin biopsies were taken and cryopreserved in nitrogen. She died a year after tissue was harvested from her ear.

It was expected to be easier than the cloning experiment of endangered gaur (Bos gaurus), as the reproductive biology of goats is better known and the normal gestation period is only five months. In addition, only certain extinct animals are candidates for cloning because of the need for a suitable proxy surrogate to carry the clone to term. ACT agreed with the government of Aragon that the future cloned Pyrenean ibex would be returned to their original habitat.

Celia provided suitable tissue samples for cloning. However, attempts to clone her highlighted a major problem: even if it were possible to produce another healthy Pyrenean ibex, no males were available for the female clone to breed. To produce a viable population of a previously extinct animal, genetic samples from many individuals would be needed to create genetic diversity in the cloned population. This is a major obstacle to re-establishing an extinct species population through cloning. One solution could be to cross Celia's clones with males of another subspecies, although the offspring would not be pure Pyrenean ibex. A more ambitious plan would be to remove one X chromosome and add a Y chromosome from another still-existing subspecies, creating a male Pyrenean ibex, but such technology does not yet exist, and it is not known whether this will be feasible at all without irreparable damage to the cell.

Three teams of scientists, two Spanish and one French, are involved in the cloning project. One of the Spanish teams was led by Dr. Jose Folch of Zaragoza, from the Centre of Food Technology and Research of Aragon. The other teams had researchers from the National Research Institute of Agriculture and Food in Madrid.

The project is coordinated by the Food and Agricultural Investigation Service of the Government of Aragon (Spanish: Servicio de Investigación Agroalimentaria del Gobierno de Aragón) and by the National Institute of Investigation and Food and Agrarian Technology (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria). The National Institute of Agrarian Investigation (INRA) of France is also involved in the project.

Researchers took adult somatic cells from the tissue and fused them with oocytes from goats that had their nuclei removed. The purpose of removing the nuclei from the goats' oocytes was to extract all the DNA of the goat, so there would be no genetic contribution to the clone from the egg donor. The resultant embryos were transferred into a domestic goat (Capra hircus), to act as a surrogate mother. The first cloning attempts failed. Of the 285 embryos reconstructed, 54 were transferred to 12 ibex and ibex-goat hybrids, but only two survived the initial two months of gestation before they, too, died.

On July 30, 2003, one clone was born alive, but died several minutes later due to physical defects in the lungs. There was atelectasis and an extra lobe in the left lung.

This was the first attempt to revive an extinct subspecies, although the process technically began before the extinction of the subspecies.