A surrogate hound gave birth to seven half-pound puppies on July 10, an everyday occurrence save that the squirmy furballs were the first dogs ever conceived in a test tube. "We each took a puppy and rubbed it with a little towel and when it started to squiggle and cry, we knew we had success," said Dr. Alexander Travis, who runs the lab at the Baker Institute for Animal Health at Cornell University's College of Veterinary Medicine. The seven puppies—the survivors of 19 embryos implanted in the mother, notes the Guardian—are a mix of beagle, Labrador, and cocker spaniel and are now healthy 5-month-olds. All were adopted except for one female who's being kept by the lab to have her own litter. The lab kept track of the puppies by painting their nails with different color polish. Travis adopted two, still known by their nail polish names, Red and Green.
In vitro fertilization has been possible in humans since 1978, but IVF efforts with dogs repeatedly failed until now. "The biology of the dog is really, really different than humans," says a reproductive physiologist for the Smithsonian Conservation Biology Institute, which works with Cornell, hailing the birth as a "huge breakthrough." Dog pregnancies last only two months and females go into heat just once or twice a year, releasing immature eggs instead of mature eggs needed for IVF. To compensate, researchers left eggs in the dogs' oviducts a day longer than normal, notes the Guardian, allowing them to mature. The lead author of the PLoS ONE paper on the feat says that doggy IVF could prove useful in everything from conserving endangered species to removing "deleterious traits from breeds," and could extend to "models for human disease" as well. (Read more in vitro fertilization stories.)