One of Europe’s oldest African bush elephants has died mysteriously aged 44 at his enclosure in a Spanish zoo.

Kibo died during the night without any signs that he was ill, baffling his keepers.

His routine was normal in the days leading up to his death and he was in close contact with a park vet.

A keeper found the elephant dead in his enclosure first thing in the morning.

An autopsy was carried out and a team of around 20 specialists, including experts from CEU Cardinal Herrera University, was unable to establish an exact cause of death.

Specialists will carry out an in-depth analysis of the animal’s samples to see if they can shed further light on Kibo’s mysterious death.

He lived at Valencia Bioparc with six female elephants and another male.

Kibo was a popular resident at the Spanish zoo and, for unknown reasons, had a single tusk.

African bush elephants (Loxodonta africana) have reportedly seen their numbers plummet by around 60 per cent in the last decade.