Most dog-lovers know that the domestic pups that have become part of our families were selectively bred for traits that blended well with humans.
Some breeds are excellent hunters, others love to swim and others still have placid natures which were perfect for nannying our children.
The majority of dogs we have as house pets today are food motivated, which makes training easy and actually enjoyable for our four-legged friends.
But there is one dog breed that has a very special affinity for food - so much so that people are calling it the greediest breed!
Can you guess which of these dogs it is?
Turn to the next page to see if you were right!
If you guessed the Labrador, you're right!
Cambridge University researchers have discovered that one in four Labradors carry a high 'food motivation' gene that causes their notoriously greedy behavior.
They believe that it is actually a genetic mutation that causes their food-focus to get out of control. The mutation causes a tendency in the breed to develop "a portly form," which, if left unchecked, can contribute to health problems like diabetes and heart disease - both of which are linked to obesity.
After comparing the labrador DNA to that of 38 other dog breeds, researchers discovered that the mutation only appeared in one other type of dog: the flat-coated retriever.
The two dog breeds are closely related to the St. John's water dog - a breed now extinct that once was used by fishermen in St John's, Newfoundland, Canada.
This mutant gene might have served the working breed well, considering they had to burn a lot of calories to stay warm while diving into the frigid Canadian waters.
But today, most of their descendants are family pets and companion animals, who don't live a lifestyle that requires all those calories.
Now that they know this mutation exists, the next steps for researchers is to learn more about how it affects the dogs at a microscopic level. This new knowledge could "open the door to developing treatment for those dogs affected by the mutation," says Yaizada Forcada, of the Royal Veterinary College.
If you've never experienced the greedy eating of a Labrador, just watch what this guy does to his two buddies in a cake eating contest: