Dogs are famous for their loyalty to humans, which evolved over thousands of years. Here’s how evolution nurtured our unique bond.

Dogs are famous for their loyalty, but what truly makes them man’s best friend? Thanks to animal researchers, we are improving our understanding of our shared history and this unique bond.

Studies have shown that dogs and humans began their shared existence anywhere between 10,000 and 40,000 years ago. While a deeper dive into the topic is necessary to better understand how dogs departed from their wolf ancestors, research indicates that dogs had already become a separate species by this time. Several factors contributed to our shared past, which may have started as humans realized dogs provided them with protection or gave them an advantage during the hunt. Dogs and people share a natural affinity for group bonding, so this proximity lent itself easily to the ties we share today. A dog’s survival depends on his ability to be part of the pack, after all, and in the modern setting, your family becomes his social group. Trusting his pack leader and cooperating for the good of the group is innate to dogs, explaining their unwavering loyalty to their humans.

Sharing close quarters with people also allowed dogs to refine the ways they communicate with humans. Studies have shown that dogs have a profound ability to read verbal and physical cues from humans, which helps them understand what we are feeling. While it is certainly in your pet’s self-interest to understand when you are in a good mood, and therefore more amenable to doling out treats, research has found that our four-legged companions can actually express empathy for humans. One study, for example, showed that compared to strangers and even food, dogs reacted stronger to the smell of their owners, which triggered the part of their brains associated with positive emotions and enjoyment. This ability to bond is unique in the animal kingdom, truly earning your dog his position as man’s best friend. The bond a pet and owner share depends on the individuals involved, and in some cases, this can lead to a codependent relationship in which a dog grows too attached to one person. This can lead to separation anxiety when you are away from home or your pet distancing himself from other members of the family, so you should work to treat codependence as soon as you notice an unhealthy pattern. If your dog’s attachment is too intense to fix on your own, seek the advice of a canine behaviorist. Though the relationship varies from pet-to-pet, one thing is clear: Dogs evolved alongside humans, establishing a special connection. What started as a reciprocal relationship in which humans fed canines in return for protection has evolved to be one of the closest cross-species bonds in the animal kingdom, thanks to thousands of years.