The Killer Shrews (1959)
Be sure to check out its companion movie, The Giant Gila Monster, which I'll post soon.
My copy of this cinematic masterpiece came from Amazon.com, which shows Kitchen And Housewares items on a search for "Killer Shrews":

I got it on this triple feature DVD for $9.99 - meaning that I paid just over three bucks for this movie. That tells you something - among other things, that $3 isn't enough to get the entire shrew documentary at the beginning (it supposedly details everything that is known about shrews, in the form of a voiceover while we pan across landscape scenes).
Opening scene: Rugged Captain and Black Stereotype sail into shore. The Black Stereotype is named Rook. Is he the comic relief character that will escape at the end with the hero and the girl? Or will he be the first serving of shrew chow?

Well, we don't technically know about the shrews yet, but Rook hasn't been very comical. He goes back to the boat for the night; meanwhile the captain meets Anne, Swedish Miss America (really!) who's really creeped out about something (killer shrews perhaps?) ...

... her father the Doctor (mad scientist?) ...

... and Jerry, the producer of this awful movie (really!) but also so much more.

On this island they have cows to milk and horses to ride ... why, it's an island paradise! But who is this squirrely creature who can't stay away from his "experiments" and his typewriter? And who keeps showing special shrews ("this is the sole survivor from group 30!") to his boss, the Doctor? It's Ratbert! I mean, Radford.

The doctor, it seems, wants to solve the overpopulation problem by breeding humans who live twice as long but twice as small. How exactly this will help, we aren't told, just as we aren't told that somehow this research involves the accidental creation of vicious dog-sized shrews. We find out soon enough, despite Jerry's warnings not to tell the Captain. Anne tells him anyway. And who let the shrews out? Why, Jerry, the irresponsible drunk. He gets drunker and irresponsibler as the night wears on. Turns out that Anne broke off her engagement with Jerry when he let the shrews out and they almost killed her. This means that Jerry and Our Rugged Captain will be fighting over Anne for the rest of the movie.

"Alright, father, since I'm the only female on the island
I suppose I have to be the love interest."
By the way, we have another Ethnic Minority Who Will Die Soon, named Mario.

Oh, and did I mention there's a hurricane coming? That's why the captain, skipper, and Anne can't all leave right away, as planned. That's why the windows and doors have to be left open.
Captain: "There'll be ample time to panic when they run out of food and go on a 24-hour forage!"
In the meantime, the shrews eat Rook (told you so), devour the cows that give milk and the horses that give rides (ah, so that's why they're there), and one gets in through the open window and grazes Mario's leg with its teeth. Mario collapses and dies instantly.
In the close-up shots, the shrews are hand puppets. In the shrews-running-around shots, the shrews are dogs with extra fur glued on. Early on, the Doctor had showed the Captain a tiny cute little shrew. Now, the Captain points to the dead costumed dog and shouts:
"Doctor! That's NOT the same animal you showed me!"
Right. It's a dog. Later, the Captain and Anne are sitting on the couch talking.
Captain: "I'll take a dull alive woman every time!"
Pretty low standards, if you ask me. Anne opens the kitchen door to make some coffee (a change from all the martinis that have been consumed up to now), and lets in a shrew that kills Ratbert.
The remaining group has, at this point, made it through the night. But then the shrews start to claw through the adobe walls. ADOBE??? Yes, adobe. Just go with it. So they leave the house and go into the fenced yard. Somebody needs to see if it's safe to run out to the boat. Of course, the scout party consists of the two guys most intent on killing each other: the Captain, and the Irresponsible Drunk, who is now drunker than he ever was. They go out, all right, and find Rook's remains, and threaten each other's lives two or three times apiece before shooting some shrews and running back to safety. They try to kill each other a few more times before the Captain gets the bright idea to lash some metal barrels together and "weld" eyeholes in them, and pretend they're a tank, inside of which they can crawl across the island (shrews can't swim). Meanwhile, the Irresponsible Drunk's competing idea is to stand on the roof with his shotgun. Then he jumps off the roof, for no reason, and becomes shrew chow.
Our remaining protagonists (the Captain, the Girl, and ... the Doctor? Who let him in the tank?) make it to the boat. The doctor says something about overpopulation. In what is the movie's sleaziest line yet, the Captain says "Well, Doctor, I'm not going to worry about overpopulation just yet!"