《瘋狂原始人》是講述一個原始人家庭冒險旅行的3D喜劇動畫片。原始人咕嚕一家六口在老爸Grug的庇護下生活。每天搶奪鴕鳥蛋為食，躲避野獸的追擊，每晚聽老爸敘述同一個故事，在山洞里過著一成不變的生活。大女兒EEP是一個和老爸性格截然相反的充滿好奇心的女孩，她不滿足一輩子留在這個小山洞里，一心想要追逐山洞外面的新奇世界。

　　《瘋狂原始人》經典臺詞

　　Guy: This is called a brain. I think that's where ideas go.

　　Thunk: Dad, I don't have a brain.

　　"Eep: My name's Eep and this is my family, the Croods. We never had the chance to explore the outside world because of my dad's one rule:

　　Eep: Never leave the cave.

　　Grug: New is always bad. Never not be afraid!

　　Eep: We never had a chance to explore the outside world, but what we didn't know was that our world was about to change."

　　"[Gran tries to eat Belt, the sloth, but Belt pulls a knife on Gran.]

　　Guy: Don't do that. He's not food. He's a pet, my pet.

　　Gran: What's a pet?

　　Guy: An animal you don't eat

　　Gran: We call those children.

　　Eep: [Smitten with Guy] Isn't this fun? We're taking our first trip together."

　　"Grug: Just think, our whole family packed together on a long, slow trip across country. We'll tell stories. We'll laugh. We'll become closer as a family.

　　[Sandy, the baby, bites Grug's face.]

　　Grug: Ah, get her off!

　　Ugga: If you're not ready to challenge her then don't look her in the eye!

　　Gran: Could you keep your big giant arms on your side of the trail?!

　　Grug: You want me to turn this family around? Do you? Because I will turn this family around so fast!

　　Thunk: Dad, I gotta go!

　　Grug: Come on, you can hold it.

　　Gran: I'm not dying on an empty stomach.

　　Ugga: Ugh, we're all Ptty tired.

　　Grug: We'll eat when we get there.

　　Gran: It's taking too long! I'm grabbing a snack."

　　"Guy: We've gotta move faster. I call them shoes.

　　Eep: [screams] I love them! Where are my feet?"

　　"Eep: Oh, I've been in that cave forever!

　　Grug: Three days is not forever.

　　Eep: It is with this family.

　　Ugga: Mom, we're ready to leave. Mom?

　　Gran: Still alive!

　　Grug: It's still early."

　　"Grug: Ideas are for weaklings."

　　"Guy: Who are you.

　　Eep: OH! Eep.

　　Guy: Let me clarify Eep. The world is ending.

　　Eep: What

　　Guy: I am calling 'The End'"

　　"Guy: I am guy.

　　Eep: Guy.

　　Guy: And this is Belt.

　　Guy: Cook, conversationalist, navigator.

　　Guy: Also keeps my pants up.

　　Eep: What are pants up."

　　"Guy: Belt, emergency idea generator activate!"

　　"Grug: Never not be afraid."

　　"Thunk: You need a name, I think I'll call you Douglas. Roll over Douglas."