It's because of a little known bible verse in Benisus chapter 3 v 34
34"And lo! The snake did approach jup-jup the monkey and he did say unto him 'see those naked ass humans over there? Well they just got hella smart from eating that Apple, I bet they will be able to kill and eat you and your kind now and truly I say to you, they shall wear your skin to cover their nakedness. Eat of the Apple too and you shall be able to outsmart them!' 35 And so Jup-jup did eat of the Apple and he did give some to his fellow monkeys and they did eat of the apples too.36 But when the snake got to hear that the monkeys did eat of the apples he proceeded to laugh heartily and declare 37 'lo now you and your kind shall be cursed, for the ilogical God that hath made all of us had decreed that none should eat of these apples, which is why he put them there and made them look so good. Now shall he curse you truly and all of your kind!' 38 When the monkeys got to hear this they hooted and screeched bitterly and they did give Chase to the snake and upon catching him they proceeded to beat him violently against a tree untill he was dead."
I hope these scriptures explain the answer to your question now? ;)