Dogs are really good at understanding humans. In fact, according to a study from Eötvös Loránd University in Budapest, most dogs understand several hundred words, and they can read human body language very well. Dogs also detect things about humans via their noses. They can smell your emotions, your blood sugar levels, whether you are sick, and so on. Unfortunately, humans tend to have trouble deciphering what their four-footed friends are saying. Whether your dog is a family pet or a service dog that has an emotional support animal (ESA) online certification, it’s important to understand their communication. Here are some tips for understanding dog language:

1. Eating grass
Some grass apparently just tastes delicious to dogs. When they are eating grass because it is tasty, they are relaxed and calm and are clearly smelling the grasses to find the tastiest bits. However, if your dog is frantically eating any grass it may have an upset stomach. Keep in mind that an upset stomach and loss of appetite can also indicate an underlying health condition—like heartworm.

2. Excessive licking
Excessive licking always warrants a trip to the veterinarian. This can indicate allergies, fleas, ticks, a hotspot, or even anxiety that causes obsessive grooming behaviors.

3. Chewing or ripping up personal items
When a puppy chews things or rips up your stuff it may be teething. Some puppies think everything in the world is a chew toy, but you, as the owner, can gently teach them what is a chew toy and what is not by diverting their attention to a Kong toy. Adult dogs may also chew or destroy the owner’s personal belongings and clothing due to separation anxiety.

4. Barking
Barking can mean many things. A soft “harr-uff” sound means “let’s play.” Short, high-pitched barks mean the dog is happy and excited, perhaps because you have treats. Many dogs announce “I see you” with one or two barks when they observe a stranger nearby. Most dog owners are familiar with “alert” barking, where the dog uses a harsh, gruff bark to indicate possible danger.

5. Growling
A more intense, loud, deep growl is a warning: the dog is sure there is danger present. A dog growling while not barking is a warning that the dog really does not like what you are doing, and if you don’t stop now, the dog may get aggressive.

6. Howling
A howling dog is usually trying to attract attention from their absent owner or their missing canine friend. Some dogs howl when they hear certain noises, such as sirens or music.

7. Tilting their heads
If a dog stares intently at you and tilts its head to one side, that means it is paying attention to you and is trying to figure out what you are talking about.

8. Giving you puppy dog eyes
Giving you puppy dog eyes means the dog wants something you have, usually whatever you are eating or if they want attention, such as pets or to get on your lap.

9. Exposing their bellies
In most cases, if a dog rolls over and exposes its belly, it wants a belly rub. Sometimes, dogs will roll over and expose their belly as a submissive pose, to humans or other animals.

10. Digging
Dogs dig for several reasons. They dig “nests” in the ground to lie in. They can easily smell things under the ground, and then they dig to find those things. And most dogs seem to enjoy digging, so sometimes they dig just because it is fun or they are bored.