Not recoverable

1987/08/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Zoologia

At least some of you can visit Regent's Park in London, at the end of which is the London Zoo. Formerly common squirrels were common in the park, but disappeared by human pressure. In 1984 an attempt was made to reintroduce the common squirrel that has failed. They remain in the park but do not reproduce. The reason is the sexual interference of gray squirrels.

Zoologists captured 10 young common squirrels in the Fife region and after getting used to being in public at London Zoo, they were released into the park. During the first twenty months the cars killed 6 and one cat another. The status of the remaining three is unknown and the review is terminated. The mystery is because before dying common squirrels have not been reproduced. The answer could be in the grey squirrel competition. Apparently, gray squirrels replace simple squirrels when covering females.

This fact reveals the difficulty of reintroducing native species. In the last century the common beetle was the only British squirrel species, abundant in all aspects. However, between 1876 and 1929 people were releasing gray squirrels from North America. These larger squirrels have replaced the common squirrel, except in some distant coniferous forests.