There is no doubt that animals have emotions like humans. Dogs are man's best friends and they feel happy when you are happy and they even miss you when you are not at home. They express happiness by wagging their tails. They feel sad when a pack member passes away. And they feel love for each and every family member. But it is important to keep in mind that these emotions are totally different from humans.
Feelings of dogs are not associated with complex thoughts. They don't have doubts or motives. Their emotions are honest and pure. Your dog is never lying when expressing love to you. It is very hard to believe that dogs have emotions but it is true.
Which emotions do dogs have?
Most people can easily read their dogs emotions. For example when you come home from work your dog dances around you wagging his/her tail and you say my pup is really happy. Dogs also have the ability to understand the languages of humans. According to science dogs have the same brain structure as humans and they can produce the same hormones the same way as humans during emotional states. Dogs also have oxytocin hormone which is secreted in humans when they feel love or affection about others. With the same chemistry and neurology it seems reasonable to say that dogs have the same emotions like we humans do.
Do they feel grief?
There are many evidences that show that dogs have the same emotions of humans when grieving. They feel sad when their owner passes away. They won't eat for days, they won't play etc. Dogs may mourn deeply just like humans do. Grief is one of the basic emotions in dogs according to the pet experts. Dogs feel sad when they are separated from their playmates and owners and you can observe this; dogs move slowly, they don't eat and sleep more. These are the common symptoms. There is a huge attunement between dogs and humans not only in terms of body language and each other gestures but emotionally as well.
According to some of the owners two dogs which lived in a household for a number of years, miss the other dog that died. Owners report that when one dog died the other gets very depressed. The surviving dog will search for the other dog around the entire house. This shows that the dog misses its playmate and pack member. Dogs have unique personalities however in the same situation they can react differently.