It's no secret that a dog is man's best friend and we are here to celebrate our furry friends on National Dog Day!

If you have a pet, you know that they provide unconditional love, reliability and companionship. But what is the science behind that excited feeling we get when we come home from work after a long day and our dog greets us at the door with a vigorous wagging tail? We've got an expert to tell you.

Phil Tedeschi is a human and animal behavioral researcher for Rover as well as a professor at the University of Denver, focusing on the connections between human beings and animals. Animals are his life and his research on this special bond is breaking barriers.

"We study the human-animal interaction in almost every capacity all over the world," said Tedeschi. "I realized early on in my career I was interested in how people and animals interacted with one another."

He even got some inspiration from a familiar name, Dr. Jane Goodall, the world-renowned scientist who studied chimps.

"Back then, Jane was studying the emotional and cognitive lives of animals and talking quite a bit about how studying animal sentience informed us about human beings," Tedeschi explained. "Her mentorship had a profound influence on me that has led me to study the field for the last 30 years."

The presence of domestic animals such as dogs has proven mental health benefits, especially for those individuals overcoming a trauma. Tedeschi and his colleague, Molly Jenkins, co-edited the book "Transforming Trauma: Resilience and Healing Through Our Connections with Animals," which explores the animal's role in lessening the impact of physiological and psychological trauma.

"A chapter in the book focuses on animal-assisted crisis response, which applies to mass-casualty situations that have a major impact on communities," Tedeschi said. "Dogs, in particular, are starting to become one of the first responders to crisis situations."

Research shows that one of the dimensions of these crisis situations is that victims often have a difficult time trusting people afterward.

"One of the ways that service dogs and professional therapy dogs are especially relevant is that dogs are seen in those communities as more trustworthy than people," Tedeschi said. "When people have been hurt by others, it's very difficult to help them overcome the circumstances until they can begin to develop relationships with people again. Dogs don't need spoken language to communicate and do this for humans."

This unseen connection is a result of physical happenings in the brain. For example, being surrounded by a safe animal changes our interpersonal neurobiology. The hormone oxytocin is released, which promotes feelings of love, social bonding and well-being. In the presence of animals such as a dog, cat or horse, the oxytocin that is released makes us more happy and talkative.

"Dogs cause us to get more exercise, to literally get up and get out of our seat and move much more often than when we are living and working in settings where we don't have those animals, therefore physically improving our health," said Tedeschi. "We get fresh air more often, we make connections with our neighbors and we improve our cardiovascular health in the presence of these kinds of animals."

Tedeschi also points out that another key component of this relationship is to remember that it is a mutually beneficial one. Your dog needs you just as much as you need them!

"Physical and emotional health are embedded in the dimension of having this healthy relationship," he said. "Dogs do this better than any other animal because they've been evolving alongside human beings for thousands of years. As a result, dogs understand human communication, body language and facial expressions in such a way that they are very successful at interacting with humans."

So to celebrate National Dog Day, run home and hug your furry friend. But Tedeschi also wants you to remember how important this bond is for your mental health.

"Your pet brings you social support, connection to your community and improves your relationship with yourself," he noted. "Animals fit into our broader efforts of health and wellness and leave a positive impact in many ways."

No wonder why we care so much about them!