Why do dogs sleep so much? This is because that is how they are physically predisposed. In fact, it would be more worrisome if your dog started spending more time awake.
This may be hard to believe, but an adult dog can sleep as much as 12 hours a day. This varies by breed, but larger dog breeds tend to need more sleep. You’ll also find that younger dogs need more naps through out the day, and can sleep for up to 16 hours. Although dogs sleep more than humans do, it is not continuous sleep. They tend to wake frequently.
These figures vary based on other factors. For instance, a dog with an active lifestyle will need more sleep than one who lounges around the house all day. Additionally, if the dog is alone all day in an empty house, he might sleep just to pass the time.