Earlier quoted context omitted.
Beavers don't build ships and move to other continents and then build dams there, wrecking the local ecology.
Are you suggesting wolfs didn’t migrate to different areas and change the ecology with their hunting? That viruses didn’t spread and wipe out populations of animals?
Same goes for viruses (I'll give you a pass on that one, it's more accepted now than "virii"): they don't float across oceans in a week, unless they're carried by birds (which most aren't).