The Pyrenean Ibex (Capra pyrenaica pyrenaica), a distinct subspecies of wild goat once native to the mountainous regions of the Iberian Peninsula, is now extinct. Also known as the bucardo, its story highlights the complex challenges of species conservation and the ambitious field of de-extinction.
The Vanished Species
The last known Pyrenean Ibex, a female named Celia, died on January 6, 2000, when a fallen tree crushed her in Spain’s Ordesa National Park. This event marked the subspecies’ official extinction. The decline of the Pyrenean Ibex over centuries was a gradual process influenced by several interconnected factors.
The Pyrenean Ibex was abundant in the Middle Ages, but its numbers sharply decreased in the 19th century due to intense hunting pressure. By 1900, fewer than 100 individuals remained, and after 1910, the population never exceeded 40 animals, confined to a small area within Ordesa.
Competition with domestic livestock such as sheep, goats, cattle, and horses also played a significant role. This competition for grazing resources led to overgrazing and reduced food availability for the ibex. The introduction of non-native ungulate species exacerbated these pressures, increasing the risk of disease transmission from livestock. Low genetic diversity and inbreeding within the shrinking population further compromised their ability to adapt and survive.
A Brief Return: The Cloning Attempt
The Pyrenean Ibex made a brief return in a scientific endeavor. Before Celia’s death, scientists collected tissue samples from her ear and preserved them in liquid nitrogen. These cells contained the genetic material used to clone the subspecies.
In 2003, a team of Spanish and French scientists employed somatic cell nuclear transfer (SCNT), a technique similar to that used for Dolly the sheep. They extracted DNA from Celia’s preserved cells and inserted it into enucleated eggs (eggs with their own DNA removed) from domestic goats. These reconstructed embryos were then implanted into surrogate domestic goat mothers.
After numerous attempts, one cloned Pyrenean Ibex was born alive via Cesarean section on July 30, 2003. This cloned female lived for only a few minutes, dying shortly after birth. The cause of death was attributed to severe lung defects. This brief life marked the first time an extinct animal had been brought back.
Lessons from a Fleeting Revival
The cloning of the Pyrenean Ibex, though short-lived, provided insights into the complexities and limitations of de-extinction efforts. The project highlighted the technical challenges inherent in reproductive cloning, evidenced by the low success rate with hundreds of embryos yielding only one live birth. Many cloned animals, including sheep, have exhibited similar physical defects, suggesting that the cloning process itself can introduce developmental issues.
Even if the cloned ibex had survived, re-establishing a viable population would have presented substantial hurdles. The clone was a female, and without any male Pyrenean Ibex to breed with, a sustainable population could not be formed. This underscores the need for genetic diversity, which is difficult to achieve from the limited genetic material of a single individual. The attempt revealed that while bringing an individual back is scientifically groundbreaking, creating a self-sustaining species requires a broader genetic pool. The Pyrenean Ibex experiment demonstrated that current cloning technology, while capable of a temporary revival, faces considerable obstacles in restoring extinct species in a sustainable manner.