How can I assign a random number to each object in an array in javascript?

Alright, so why am I asking this question? Because I am making a simple evolution simulator. In it, each creature will get a random amount of food each generation. The amount of of food each creature gets is crucial to if it survives or not. Since the only way I see it working is in an array(and I'm not good at arrays) can you help me find a way to assign these numbers to objects within the array?

I've looked through multiple websites for answers and none hit the dot. I also don't have any code so can you submit some code so I can see what I have to do?