The Longest Living Dog Breeds Are Tiny, but Why?

The French bulldog's life expectancy is only 4.5 years, and none of the other flat-faced breeds – no matter how small – were found to have an average lifespan of more than 7.8 years. Large breeds die of cancer more often than small breeds. It takes a chihuahua about 10 to 12 months to grow to full size, but that size usually maxes out at only about 8 inches,. A great dain can be over 30 inches or 80 centimeters tall, and some 175 pounds, around 80 kilos.