I found the giant shrews more believable than the duck walk to the shore.
Internet Archive has it online:
1000 Misspent Hours calls it "one of the last great monster movies of the 1950’s" and says
Hiding beneath the bargain-basement special effects is an extremely economical, shockingly suspenseful movie, with unexpectedly complex characters, a fast-moving, engaging story, and quite a bit of imagination.
BMovieGraveyard has a page devoted to this movie that includes character sketches, a plot overview and walk-through of the film, still shots, and lots of commentary.