Gray squirrels may look cute and harmless but they are responsible for driving the European red squirrel toward extinction.

Driving the equally adorable European red squirrel toward extinction in what some say 100 worst environmental offences. The U.K.’s gray squirrels not only sap resources from the native reds, but carry and spread squirrel pox—a disease that is decimating their red cousins. Yikes!

The problem of invasive alien species is not unique to the UK. From different alien plant species all over the Sea to Sky, to numerous grey squirrel sightings; biological invaders are flourishing worldwide, devastating native plants and animals in their wakes.

If anyone has sightings, or questions they can contact us or the invasive species council.