This image was originally found at:
http://www.foxnews.com/scitech/features/sputnik/time1.sml

Accompanying text:
November 3, 1957 - Sputnik 2 is launched by the U.S.S.R., remaining in orbit until April 13, 1958. On board is a dog, Laika, who orbits for 7 days before being put to sleep.

Image Caption:
Sputnik 2 launched the first living being into space, a dog named Laika

*** WEBMASTER'S NOTE: I do not believe this is a picture of Laika, whose facial hair was short and dark; this photo shows long, light-colored hair. I suspect the pictured pooch might be the same one listed on the LAIbrary's miscellaneous images page under "dog in space gear" (who resembles Belka way more than s/he does Laika):