Presidential pets have affected U.S. history. In some cases, they have increased a president's popularity or been a factor in their unpopularity.

Have you seen President Barack Obama's new Portuguese water dog, Bo, playing on the lawn at the White House? He's a lively puppy who likes to race with Malia and Sasha. He has also chewed on a few things, as all puppies do. Overall, he has probably helped the president's image.

Bo joins a long list of presidential pets, starting with George Washington's American staghounds and black and tan coonhounds, as well as a donkey and his horse, Nelson.

Only President Chester Arthur had no known pets. Perhaps that is one reason he is not often remembered.

Thomas Jefferson was partial to Briard dogs and a cocker spaniel named Dot, but he also had two bear cubs and a mockingbird. Benjamin Harrison kept a goat named Whiskers, a collie named Dash and two opossums named Mr. Reciprocity and Mr. Protection. William McKinley was partial to angora kittens.

Teddy Roosevelt was famous for his many pets. His six kids had nine dogs -- mostly terriers -- two cats, a garter snake, two ponies, a pig named Maude, a badger, a piebald rat, four guinea pigs, a macaw, a hen and a one-legged rooster.

During World War I, Woodrow Wilson kept a herd of sheep on the White House lawn. He did this so the first family would appear to support the war effort. Help was difficult to get, and the sheep kept the lawn mowed. Wool from the sheep was auctioned and the money donated to the American Red Cross.

Warren Harding and his family had a birthday party for their dog, Laddie Boy. They invited other dogs to the party and had a dog biscuit cake.

George W. Bush's dog Spotty was the only pet to live in the White House during two administrations. Spotty was the son of President George H. W. Bush's dog, Millie. George and Laura Bush also had a cat named India and two Scottish terriers named Barney and Miss Beazley. A longhorn cow named Ofelia resides on the Bush ranch in Texas.

The most famous Scottish terrier was Fala, President Franklin Roosevelt's dog. Fala and the president were inseparable. During FDR's run for a fourth term as president, Fala was accidentally left behind when Roosevelt was visiting the Aleutian Islands. The president sent ships back to rescue his dog. For this, Roosevelt was accused of wasting thousands of taxpayer dollars to retrieve Fala. Speaking after the incident, he said, "You can criticize me, my wife, and my family, but you can't criticize my little dog. He's Scotch and all these allegations about spending all this money have just made his little soul furious." The "Fala speech" was later credited with turning the election around for Roosevelt.

Presidential pets have influenced several other elections. Herbert Hoover got a German shepherd, King Tut, during his campaign. Pictures of him and the dog were sent all across the country. Perhaps the warm picture of him and the dog helped win the election.

Many believe that President Lyndon Johnson's image was damaged when photographs of him picking up his two beagles, named Him and Her, by their ears were circulated. Many were outraged, and animal lovers criticized him roundly. Others were not upset by the pictures. President Harry Truman was reported to have said "What the hell are the critics complaining about; that's how you handle hounds." It might not have affected his presidency, but the scandal did alter Johnson's image for many.

Richard Nixon, running for vice president with Dwight D. Eisenhower in 1952, was accused of having a secret slush fund. In his famous "Checkers speech," named after his dog, he denied the slush fund but did say "there is one thing I did get as a gift that I'm not going to give back." The gift was Checkers, a black and white cocker spaniel given to his daughters. The speech increased his support and prevented him from being kicked off the ticket. Mimi Eisenhower recommended he remain on the ticket because he "was such a warm person."

Some of the presidents had less traditional pets. Herbert Hoover had two pet alligators along with his nine dogs. Calvin Coolidge had a real zoo: many dogs, two raccoons (they were leash trained), a donkey, a goose, a bobcat, two lion cubs, a pygmy hippo, a wallaby and a duiker -- a small antelope.

Andrew Johnson fed the white mice he found in his bedroom. John Quincy Adams was fascinated with his silkworms and alligator.

Abraham Lincoln kept goats, a couple of dogs, a turkey, a horse and a rabbit. The turkey, Jack, was pardoned by Lincoln when his 10-year-old son Tad begged for Jack's life. No other turkeys received a pardon until John F. Kennedy said he couldn't eat a turkey he knew. Now it is a hallowed tradition for the national turkey at Thanksgiving to be pardoned and allowed to live out its natural life in a sanctuary setting.

Occasionally, gifts from world leaders went straight to the zoo. James Buchanan received a herd of elephants from the king of Siam (now called Thailand). The sultan of Oman gave Martin Van Buren a pair of tiger cubs.

Pets, for the most part, have been good for presidents. They humanize the presidency. They make the president seem like the majority of Americans who love animals.

This information, plus much more, can be viewed on the Web site wikipedia.org/wiki/List_of_United_states_Presidential_pets.

Delbert Marshall, Hays, is a member of the Generations Advisory Group.