A comprehensive new study of nearly 75,000 doggy deaths between 1984 and 2004 provides an in-depth look at the demographics of canine mortality. The study, conducted by University of Georgia researchers and published in the Journal of Veterinary Internal Medicine, offers data that backs up, and in other cases, contradicts, common wisdom about what sends man's best friend to heaven. "If we can anticipate better how things can go wrong for dogs, we can manage their wellness to keep them as healthy as possible," says one of the study's authors, Dr. Kate Creevy. Here, five takeaways from the study:

1. Little dogs live longer
"The old addage that small dogs live longer? That's true," says Jill Rosen in The Baltimore Sun. With most mammals, the bigger you are, the longer you tend to live. But the study found that the opposite is true for dogs.

2. Big dogs and little dogs die for different reasons
Researchers learned that bigger dogs are most likely to die from musculoskeletal disease, gastrointestinal disease, and cancer. Smaller dogs are more likely to die from metabolic diseases, like diabetes and Cushing's disease.

3. Some of our favorite breeds are especially prone to cancer
Boxers and golden retrievers are especially susceptible to cancer, with 44 and 50 percent, respectively, of their deaths attributed to it. The Bouvier des Flandres, a somewhat rare breed, is also quite prone to cancer: the disease causes 47 percent of that breed's deaths.

4. Chihuahuas should watch out for cardiovascular disease
For toy breeds, it's not cancer, but cardiovascular disease, that often leads to death. Nineteen percent of the Chihuahuas studied, and 21 percent of the Maltese, were killed by cardiovascular disease.

5. Preventive care is key
Creevy says preventive care is almost always preferable to post-diagnosis treatments. And just as it is for humans, regular exercise and maintaining a healthy weight are critical to dogs' longevity.

Sources: Baltimore Sun, Veterinary Practice News, ScienceDaily, Wall Street Journal