Random Insult Generator (Randomizing Results)

I've written a random insult generator. It is fine, and works well to what I need. The problem is that when I run the program more than once, the insult is the same every time, unless I copy all the vars again. Here is my code:

var bodyPart = ["face", "foot", "nose", "hand", "head"];
var adjective = ["hairy and", "extremely", "insultingly", "astonishingly"];
var adjectiveTwo = ["stupid", "gigantic", "fat", "horrid", "scary"];
var animal = ["baboon", "sasquatch", "sloth", "naked cat", "warthog"];

var bodyPart = bodyPart[Math.floor(Math.random() * 5)];
var adjective = adjective[Math.floor(Math.random() * 4)];
var adjectiveTwo = adjectiveTwo[Math.floor(Math.random() * 5)];
var animal = animal[Math.floor(Math.random() * 5)];

var randomInsult = "Your" + " " + bodyPart + " " + "is more" + " " + adjective + " " + adjectiveTwo + " " + "than a" + " " + animal + "'s" + " " + bodyPart + ".";

randomInsult;
"Your nose is more insultingly stupid than a warthog's nose."
randomInsult;
"Your nose is more insultingly stupid than a warthog's nose."

What I'm trying to do is when I run randomInsult; again, I want a different result.