From the beginning the White House has been pretty open to animals. Perhaps this is because our early presidents were farmers and they had depended on and cared for animals. Many early presidents brought their own animals or pets to the White House. So animals and pets have always been welcomed at the White House.
Before moving into the president's house in Philadelphia in 1791, President George Washington ordered that the straight rear walls of the main two rooms be rebuilt into a semi-circular form, or bows. The bowed shape apparently worked well for the “levees” or formal receptions that President Washington conducted on a regular basis. These bowed walls may just be the inspiration for the oval rooms in the White House.