11 “Eco-Horror” Movies that Shocked the 1970s

In the 1970s, a new breed of scary movie came clawing its way into theaters, and with “eco-horror” cinema, film lovers got to experience a darker side of Mother Nature.
A scene from 'Frogs' (1972).
A scene from 'Frogs' (1972). / United Archives/GettyImages

What did Richard “Tricky Dick” Nixon have to do with an obscure little horror film about giant, man-eating rabbits? More than you’d probably think. 

It all goes back to the rise of environmental activism after World War II, as issues like pollution, deforestation, and laws around endangered species all became hot-button issues. Books like the 1962 call-to-arms bestseller Silent Spring by Rachel Carson contributed, too, as the tome linked a sharp decline in wild bird populations to the overuse of DDT, then a commonly used insecticide.

Silent Spring sold a million copies within two years and underscored how significant these mounting concerns over environmental safety were, while disasters like the 1969 Cleveland-area river fire triggered an even greater outcry. In response, then-President Nixon established the Environmental Protection Agency (EPA) in 1970, and Earth Day was born that very same year. 

Hollywood kept pace with the times, and a new breed of scary movie came clawing its way into theaters. Dubbed “eco-horror” cinema, films in this genre pit mankind against Mother Nature and often imagine a world where human greed, hubris, or just plain old carelessness have pushed the environment to its absolute limit. Something’s got to give, and when the proverbial dam finally breaks, the human characters within a film are often left to the mercy of everything from killer bugs to mutant fish. 

Today, the 1970s are fondly remembered as the golden age of eco-horror. Here are 11 must-see titles from that bell-bottomed decade that you don’t want to miss.

1. Frogs (1972) 

Some might say revenge is a dish best served slimy. Sam Elliott—sans mustache—stars in this oddball morality tale from director George McCowan. Elliott plays wildlife photographer Pickett Smith, a guest at the island mansion of Jason Crockett (Ray Milland), a cranky Southern millionaire who is hosting a birthday party around the 4th of July. The only problem? His guests keep getting murdered by frogs, snakes, spiders, alligators, and the like. You can hardly blame the animals for lashing out though; as the audience soon learns, Crockett has polluted the land with dangerous pesticides.

Frogs had its critics when it came out in 1972, but the movie felt topical. Pesticides were all over the news that year, which is when the EPA issued a crackdown on DDT. The film’s marketing campaign underscored its conservationist message; in the official trailer, the narrator notes: “Suppose nature gave a war … and suppose that the polluters, the species on Earth called man, were the enemy in that war.”

2. Night of the Lepus (1972) 

Based on The Year of the Angry Rabbit by Russell Braddon, Night of the Lepus just might be the greatest lagomorph horror movie ever made. (Granted, there’s not much competition.) The plot gets rolling when an ill-conceived lab experiment creates a horde of bloodthirsty rabbits. Did we mention that each one’s about the size of a forklift, too? Because yeah, that’s also a factor here—and the effects team used a combination of live rabbits, miniature buildings, and the classic “grown-man-in-a-killer-bunny-suit” technique to pull it off.

Clearly, none of this is great news for the Arizona town these hopping carnivores decide to invade. “The script was quite good,” said actress Janet Leigh (Psycho), who stars in the flick. “The only thing that nobody had the foresight to see was that even if you make a rabbit 6 feet tall, he’s still an Easter Bunny. You just want to burst out laughing because you have this herd of giant rabbits that are supposed to be menacing, and they’re bunny rabbits. There was nothing we could do to make them frightening.”

3. Grizzly (1976) 

Grizzly is considered one of the first Jaws copycats—though it takes the action to dry land, exchanging the killer shark for a killer bear. Instead of slaughtered beachgoers, we get a cast of perfectly edible campers at a forested national park.

Shot in Clayton, Georgia, Grizzly was a financial hit (if not a critical one), reportedly grossing $30 million against its $750,000 budget. A sequel, titled Grizzly II: Revenge, began production in 1983, but wouldn’t end up being released until almost four decades later, in 2020. Speaking of that latter movie: It’s got an early attack scene which includes not one, not two, but three future celebrities: George Clooney, Charlie Sheen, and Laura Dern. 

4. The Food of the Gods (1976)

You are what you eat, and when it comes to The Food of the Gods, that’s exactly what you’re in for. The 1976 grindhouse flick centers around a mysterious ooze that, if consumed, turns animals into giants. When a Canadian farmer discovers the stuff, he uses it to grow extra-large chickens. But his birds aren’t the only ones who take a liking to the goo. Before long, the area is swarming with colossal rats and wasps that—surprise!—decide to go on a killing spree.

The Food of the Gods, which was adapted from a 1904 H.G. Wells novel, used prop animal heads for certain shots. Other scenes involved live rats scuttling over miniature sets à la Night of the Lepus. And in case you were wondering, critics absolutely tore this movie to shreds: Roger Ebert gave it a one-star rating while his longtime partner Gene Siskel awarded it just one half of a star in his scathing Chicago Tribune review. Ouch.

5. Squirm (1976) 

Squirm was inspired by a childhood science experiment. As kids, director Jeff Lieberman and his older brother once used electrified model train gear to draw wriggling earthworms out of the soil in their backyard. Good thing those creepy crawlies didn’t feast on human flesh—unlike the very angry, very hungry worms who eat their way through a Southern town in Lieberman’s directorial debut.

MGM released this gorefest horror flick in 1976. Fast-forward to 1999, when the cult TV series Mystery Science Theater 3000 featured (and picked on) Squirm in a season 10 episode. Lieberman wasn’t pleased. “I don’t care about goofing on the movie, I tell the audience to goof on the movie,” he explained to Birth. Movies. Death. in 2013. “What I was furious about is that some jerk at MGM sold it to them. They pay so little.” Lieberman owns a percentage of the film and believed getting the Mystery Science Theater treatment would “cheapen the value of the movie from then on.” 

6. Day of the Animals (1977) 

A shirtless Leslie Nielsen fights a bear in this movie and—spoiler alert—he loses. That might be one of the big takeaways from 1977’s Day of the Animals, which was directed by William Girdler, who had made Grizzly only a year prior.

This time, Girdler had a whole menagerie of killer beasts to work with, as Day of the Animals shows helpless people being devoured by dogs, swarmed by rats, and, in one case, pushed off a cliff by some grouchy hawks. You might call that cruelty, or you might call it karma. According to the movie, those critters only started murdering people because they were literally driven insane after mankind weakened the Earth’s ozone layer. (Ozone depletion and the products responsible for it had become a serious issue by the 1970s; a 1974 scientific research paper about this very topic won a Nobel Prize for its authors.)

7. Orca (1977) 

“Nature’s greatest pricks.” That’s how Captain Nolan, played by Richard Harris, describes Orcinus orca, a marine mammal better known as the killer whale. He’s got no love for the species; after slaughtering a pregnant female near the coast of Nova Scotia, Nolan is stalked to the ends of the Earth (literally) by its vengeful mate.

Orca was produced by Dino De Laurentiis, who was fresh off his 1976 King Kong remake, starring Jessica Lange. Hoping to outgross Jaws, De Laurentiis ordered scriptwriter Luciano Vincenzoni to “[find] a fish tougher and more terrible than the Great White.” We won’t say how, but at one point in this movie, the titular whale manages to set a coastal village on fire. Oh and while you’re here, keep an eye out for a young Bo Derek, who makes a pre-10 (1979) appearance in the flick.    

8. Empire of the Ants (1977)

Empire of the Ants is another eco-horror flick inspired by an H.G. Wells story, and it has a lot in common with The Food of the Gods. Both movies are about creatures who grow to unnatural sizes when their diets change; this time we get to see giant ants (“gi-ants?”) that’ve bulked up by eating radioactive waste.

Empire of the Ants and The Food of the Gods were also directed by the same person: B-movie legend Bert I. Gordon. He created the visual effects for both films as well, and Empire tricks the eye by merging close-up ant footage with wider shots of the human characters. “Of course, we never saw our foes [the ants],” said actor Robert Pine in an interview with film historian Tom Weaver. “To show you the importance of the human beings in this picture, there was an 11-week shooting schedule … five weeks for the human beings and six weeks for the ants.” 

9. Piranha (1978) 

How’s this for a backhanded compliment? Steven Spielberg himself called Piranha “the best of the Jaws ripoffs.” Ripoff or not, the 1978 film by director Joe Dante offers up some biting political commentary: It’s all about a Texas river system that gets infested with genetically altered super piranhas.

Turns out, the creatures were top-secret bioweapons the U.S. government had engineered for the Vietnam War. “Our goal was to develop a strain of this killer fish that could survive in cold water and then breed at an accelerated rate,” admits their creator, a beleaguered scientist played by Invasion of the Body Snatchers (1956) alumnus Kevin McCarthy. One of the hardest scenes to shoot featured actress Belinda Balaski, whose character is dragged underwater and eaten alive. Crew members had to pull her across a swimming pool with a long rope—after she’d already been covered in rubber piranhas. What a trooper!   

10. The Swarm (1978) 

By now, you may have noticed a trend of “nature strikes back” movies that somehow managed to bag celebrity talent. The Swarm cast perennial Oscar darling Sir Michael Caine in the lead role, and his interest was purely financial: Caine said he only took the job because his mother “needed a house to live in.” (He said the same thing for his appearance in 1987’s critically reviled Jaws: The Revenge, claiming: “Then I made Jaws 4 because [my mother] was lonely and I needed to buy her a bigger house, which she could live in with all of her friends. It’s that simple.”)

A box-office bomb about invasive African killer bees, The Swarm had a theatrical runtime of 116 minutes, though a longer, 156-minute cut of the film is now available on home video. It’s estimated that somewhere between 15 million and 22 million live bees were used in the production. Some of them reportedly even pooped on Caine

11. Prophecy (1979) 

When a New England paper mill starts illegally dumping mercury, the wildlife doesn’t react too well. Enter Katahdin, a mutated bear who goes after lumberjacks and campers. The carnage eventually leads an EPA representative to the scene, along with his pregnant wife (played by Talia Shire, of Rocky fame).

Though most critics panned this 1979 film from director John Frankenheimer (The Manchurian Candidate), it won over novelist Stephen King. “I must admit here that I not only liked Prophecy, I actually saw it three times … For me, settling into Prophecy is as comfortable as settling into an old easy-chair and visiting with good friends,” King wrote in his 1981 nonfiction book, Danse Macabre.

Prophecy helped start the decades-long trend of American films shooting on location in Vancouver, Canada to capitalize on tax incentives and low production costs. Our pal Katahdin is yet another monster brought to life by costumed actors: One of the suit performers who portrayed the beast onscreen was the late Kevin Peter Hall. An actor of great stature, standing over 7 feet tall, Hall would go on to play Harry the lovable sasquatch in Harry and the Hendersons and the man-hunting creatures in the first two Predator movies.