Want proof that the connection between humans and their pets is a strong one? Look no further than the White House. For centuries, presidents have been proud pet owners — some even having multiple animals during their time in the Oval Office. You've probably heard of Bo, canine-in-chief of the Obama administration. But did you know that there have been pet alligators on the grounds of 1600 Pennsylvania Avenue? How about goats? Guinea pigs? Can you guess which animals were the pets of past presidents? Test yourself, below. You may be surprised by the results.