Obamas and Bo and other first pets
First dog Bo plays with a ball on the South Lawn of the White House. (Oct. 26, 2009)
President Barack Obama is almost jerked off his feet as he shows off Bo, the newcomer to the family. The 6-month-old Portuguese water dog is joined by Obama daughters Malia, left, and Sasha on the White House's South Lawn. (April 14 2009)
President Barack Obama's dog Bo walks away from Air Force One after a vacation on Martha's Vineyard with the Obamas. (Aug. 30, 2009)
Bo takes a time out from playing in the Rose Garden outside the White House.
Malia and Sasha Obama's 6-month old Portuguese water dog named Bo seen on April 12, 2009. White House Photo
President Lyndon B. Johnson holds up his dog Her by the ears so photographers can shoot some photos, as White House visitors look on.
Richard Nixon is seen with his dog Checkers, at his home in the Spring Valley neighborhood of Washington, D.C.., in this file photo.
President Gerald R. Ford often sat with his dog Liberty, a golden retriever, in the Oval Office.
First lady Barbara Bush and her granddaughter, Marshall Lloyd Bush, visit with first dog Millie and her six puppies in the residence of the White House on March 18, 1989. Millie, a springer spaniel was "first dog" in the Bush White House, and namesake of a book that offered a dog's-eye view of the presidency.
Socks the cat peers over the podium in the White House briefing room in this file photo. A White House groundskeeper was walking Socks when he stopped and lifted the cat to the podium.
Presidential dog Barney, left, prepares to acquaint himself with Miss Beazley, the Scottish terrier pup given to first lady Laura Bush as a birthday present by President George W. Bush, during an event at the White House. The dog was named for the character Uncle Beazley, a dinosaur in Oliver Butterworth's children's book, "The Enormous Egg."