You know how they say when a bunch of women live together their “cycles” can sync up? Now think about this: What if a bunch of fellows lived together and it made the size of their naughty bits sync up? Well that is EXACTLY what happens with male ducks.

According to a study out of Yale on duck penii…yes, those fine Ivy League schools are now devoting resources to the study of “duck junk”…the packages of male ducks grow or shrink depending on which duck or ducks they hang out with.

If a male duck is living near other male ducks, his appendage can grow. It can grow up to TEN INCHES LONG…which is more than half his body length.  Jealous?

Now we know why Donald Duck didn’t wear pants!