Now We Know How It Happened! A United Ark!

Now we know why Unicorns and Dinosaurs no longer exist:

They were obviously the ones who either volunteered or were thrown off the United Ark! (source)

BTW, if you don't read Bizarro.com, you are missing out.  Let's see, they are on my regular reading list, along with xkcd.com, Funky Winkerbean, Jesus and Mo, and Non-Sequiter.