The Obamas talked about rescuing a dog from a shelter. They ended up getting pup Bo as a gift from friend Sen. Edward Kennedy, D-Mass., but it turns out the First Family has become part of a 70-year journey to save an entire breed by bringing home a Portuguese water dog to become the nation's First Dog. It's a choice that wouldn't have been possible just 30 years ago, when the breed hovered on the brink of extinction.

Once quite common along the coast of Portugal, the Cão de Água (as they are known there) helped herd fish into nets, retrieve broken equipment, and carry messages between ships. But the breed started disappearing in the beginning of the 20th century, when, according to the Portuguese Water Dog Club of America's history of the breed, technology made them redundant. By the 1930s, the breed had almost disappeared.

One man helped change that. Vasco Bensaude, a wealthy Portuguese businessman, acquired one of the few remaining working dogs, and in 1937 started breeding what would become recognized as the modern Portuguese water dog.

It took another 20 years for the breed to make it to America. The first pair came to the U.S. in 1958, but the breed remained on the edge of extinction until the mid-1970s, at which time, there were just 25 left in the world, 12 of which were in America. In 1972, a group of 16 people met in New Canaan, Conn., to form the Portuguese Water Dog Club of America and create a breeding program. Ten years later, the American population had blossomed to more than 650 animals.

Today, Portuguese water dogs aren't exactly common, but, especially with their newfound public profile, they seem unlikely to disappear again any time soon.

Alas, like all purebreds, the Portuguese water dog suffers from a number of potential genetic diseases. Since all modern water dogs descended from just a few individuals, they have a very small genetic base, which results in conditions such as hip dysplasia, eye problems such as cataracts, and heart problems that can be fatal in juvenile dogs that carry a certain recessive gene. The PWDCA has "strong recommendations" in place designed to keep these conditions from being transmitted to new generations.

It's also worth pointing out that even though the Portuguese water dog almost disappeared, breeds of dogs can't really go "extinct," since all dogs are members of the same species (Canis lupus familiaris), itself a sub-species of the gray wolf. "Breed" is not a part of the hierarchy of biological classification's eight taxonomic ranks, and is really just based on genetic likenesses such as hair and body style.

But that doesn't make Bo, the new First Dog, any less special. Welcome to the White House, little guy.

Image: Portuguese water dog, via Wikipedia