Best Of MetaFilter

Shopping cart thrown in a lake. Birds flying in the background by Ivan Radic (cc by)

Recently metalloid biologists have made the exciting discovery that in fact, bicycles and supermarket trollies are NOT as previously thought separate species, but are in fact dimorphic male and female forms of the same organism.

a pair of island foxes, from the National Park Service via Wikimedia Commons

"[I]t turns out that fox genitalia is weird...."