Four years old for a dog is equivalent to about 35 years old for a human. It depends on the breed of the dog. Generally, the life span of large dogs will be shorter, so when converted into human age, it will be older, while the life span of small dogs will be longer than that of large dogs. Dogs are longer, so their age in human terms is smaller.
Tips:
A dog’s four years old is middle age, and its body functions will begin to decline and symptoms of aging will appear. Pay more attention to your dogs.