If you visit Google Russia today, you will see two friendly looking dogs in space suits. Their names are Belka and Strelka (Белка и Стрелка ) and they are two dogs, amongst many, that the Soviet Union sent up to space to test safe space travel. These dogs spent a full day on Korabl-Sputnik-2 (Sputnik 5) on August 19, 1960. You can learn more about the dogs at Wikipedia.
For all those cat lovers out there, I think this is the first time Google has a dog in their Doodle. I can't remember there ever being a cat doodle, but I can be wrong.
Here is the logo:
Forum discussion at Google Blogoscoped Forums.