Recent bad news that a rat has been found on the Galapagos - presumably coming with a load of tourists. Impossible to stop once international large-scale traffic occurs.
It can happen with larger animals:
'There was much joy to be had in the Westmorland Gazette with the news
that a wily possum had hitched a lift from Oz to the South Lakes Wild
Animal Park in Dalton-in-Furness, via Dover.
' "Pickles the Australian brush-tailed possum got a big 'G'day' from
staff at his new home," said the Gazette. "The mischievous marsupial
somehow sneaked into the crate when it left Australian shores last
month but managed to remain hidden for most of the journey."
Marvellous stuff - watch the super uber geil cute video of said
marsupial here (
The Westmorland Gazette: breaking,video and regional news for English Lake District, Cumbria, Lancs
).