Emma Stone voices Eep, a cutely brutish cavegirl (think Fiona from “Shrek,” only with worse posture and better skin) who yearns to see what’s over the horizon. Or out there in the dark. Or at least beyond the monotonous confines of her family’s craggy canyon home. But the movie does an entertaining job of impressing on us what a struggle survival is at the dawn of man. It’s an all-hands-on-deck family action episode just to snag a few precious drops of proto-emu egg yolk. There’s lots of cleverly rendered anthropological skittishness in response to the unknown — which is virtually everything. And for Eep’s dad, Grug (Nicolas Cage, cartoonish in every sense), “new” is inherently synonymous with “deadly.” So Eep isn’t going anywhere.

Until she does go somewhere, of course. She’s lured from her cave by Guy (Ryan Reynolds), a semi-evolved wanderer with chiseled features instead of a sloped forehead, an ability to kindle fire, and an understanding that cataclysmic geological change is coming. Soon he’s got the entire family joining him on a visually colorful quest to get to higher, safer ground, with Grug disapprovingly furrowing his monobrow throughout. (The rest of the likable Crood brood includes Catherine Keener as the mom, Clark Duke as Eep’s brother, and Cloris Leachman as their resilient granny — source of some nettlesome-mother-in-law humor that feels like a further ode to “The Flintstones.”)

Some of the exotic landscape the group trailblazes looks imported from “Avatar” — happily, bringing that immersively dimensionalized, eye-catching quality along with it. If the flora is familiar, though, the fauna is unique, as animators Chris Sanders (“How to Train Your Dragon”) and Kirk DeMicco (“Space Chimps”) clearly put in extra hours brainstorming their dizzying stampede of hybrid critters. Among the species that “Ice Age” overlooked: owl-headed wildcats, gator badgers, flamingo-spliced piranha, giraffe-spotted elephants, and land whales.