Understanding the complexity of the human-pet interaction is this question: Why do so many of us become pet parents?

The simple answer is it makes us feel good. We like the unconditional love. Whether you're having a bad day or a good day, dogs and cats love you just the same.

Also, taking care of animals gives us a sense of purpose. Your pet depends on you, and you depend on them. According to the CDC literature shows bonds between people and pets result in a range of benefits, including:

- decreased blood pressure

- decreased cholesterol levels

- decreased triglyceride levels

- decreased feelings of loneliness

- increased opportunities for exercise and outdoor activities

- increased opportunities for socialization

Here's the secret ingredient to all the upsides: oxytocin. Oxytocin, which is produced in the brain’s hypothalamus, is the "cuddle" or "love" hormone, a natural "feel good" chemical. It is released when we connect intimately, like snuggling. That rush of oxytocin enhances the sense of connection.

Even looking at each other can trigger the hormone. In one study at Duke University in Durham, North Carolina dogs experienced a 130 percent rise in oxytocin levels, and owners a 300 percent increase. The longer they looked into each other's eyes, the higher the oxytocin release.

Scientists say this suggests human-dog interactions spark the same type of feedback loop that occurs between mothers and infants. That being the case, it's not surprising that we feel so close to our dogs and our dogs feel so close to us. It's a bond fueled by oxytocin. It's the same bonding hormone that is prevalent  between children and their parents, and between spouses.

Of course, the human-dog relationship rarely stops at gazing. Add in some petting and tail-wagging and the mutual response grows stronger. The oxytocin can be elevated by a single meeting with a dog, but longer-lasting relationships with frequent gazing and belly rubs and scratching behind the ears intensify the bond.

Any pet owner can tell you the love is real. Now we have the science to back it up.