Remember back in 3rd grade or so, when you learned about the different ways animals have evolved to meet the changing conditions of their environment? Like how whales used to have hind legs, and so on... well, this is sort of like that.

It seems that the plethora of delicious cuisine offered throughout New York City is so good, that mice's digestive systems are actually evolving, in order to be able to digest more human foods.

How do we know this?

Well, two students; Stephen Harris of the State University of New York and Jason Munshi-South of Fordham University, were interested in the difference between NYC mice in comparison to those living in rural areas.

So, they caught 48 white-footed mice from within the city, as well as from nearby rural areas. After close examination, the results showed that the "city dwellers" had larger livers with more scar tissue, and also showed genetic differences which are said to be correlated to "non-alcoholic fatty-liver disease."

This disease can be attributed to the body having to break down a high amount of fatty acids, usually from fast foods.

The conclusions of this are not absolute, being that the sample size was too small to be certain. There is also the possibility that these mice are experiencing a digestive change from foods other than human fast food waste, such as the abundance of nuts or seeds available in NYC parks. 

Deciphering what their diets consist of and where exactly it is coming from, will take further research.

So now we're wondering, are mice looking for a diet upgrade and weaseling their way into scoring more fast food dishes? Have we got an entire species of "pizza rat" on our hands? (By the way, if you don't recall that famous rat filmed with an entire slice of pizza in the NYC subway system,  jog your memory with this now infamous video below.)  

[via newscientist] [Feature Image Courtesy flickr]