They got under a barrol the barrol had a slit in the front so they could see where the were going it was a boy and a girl under the barrol they made their way to the water where a boat sat they got in the boat the fanged dog thing did not like the water that's how the two made it to safety.

The Killer Shrews (1959)
Wikipedia synopsis:
Thorne Sherman and his first mate, Griswold, deliver supplies to a group on a remote island. The group, consisting of a scientist named Marlowe Cragis, his research assistant Radford Baines, the scientist's daughter Ann, her fiancé Jerry Farrel, and a servant named Mario, meet the two men and advise them to stay in the house because a hurricane is approaching. Thorne goes, but Griswold stays with the boat. On the island, a doctor works to make humans half-size. This apparently will reduce world hunger, as smaller humans would presumably eat less. Unfortunately, his experiments have created some giant, venomous shrews. Thorne and Ann begin to fall in love, which angers Jerry. As the shrews run out of smaller animals to eat, they eat Griswold and close in on the people in the house, ultimately breaking in through the basement. It is discovered that the shrews have a poisonous bite, as a small single bite is enough to kill Mario. The poison kills Radford, and the shrews force the group (save for Jerry, who wants to stay) out of the house to escape to Thorne's boat. They do this by making impromptu armor out of oil drums and crawl to the beach lashed inside them. Jerry is killed by the shrews after he changes his mind and chases after the others, but the rest manage a successful escape to the boat.

The Killer Shrews - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/The_Killer_Shrews)

You can watch the complete movie here:
The Killer Shrews (1959) Full Movie - YouTube (http://www.youtube.com/watch?v=ObdUDkA7Twk)