It's My Cat in a Box

Why does my cat, Finn, love cardboard boxes so much? They have become his new favorite place to sleep and this past week there was a box in my room, the kitchen and the TV room until I said enough and threw two of the fur covered disintegrating things away. He seems to miss them. But I miss the days when he used to sleep on my bed.

I guess it's normal for cats to like to squeeze themselves into tight places. As you can see in these pictures, Finn is a big boy and is essentially crushing the shit out of the box he is sitting in. He lost interest in it after it eventually became a three sided dug out. But what does the box remind him of in the wild? A little nest or lair or hole?