《瘋狂原始人》是講述一個原始人家庭冒險旅行的3d喜劇卡通片。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，在山洞裡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裡，一心想要追逐山洞外面的新奇世界。
《瘋狂原始人》經典台詞
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 pretty 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."