Like humans, dogs go through different moods depending on the moment and the situation they witness. Sadness, joy, fear, or restlessness, are some of the feelings we share with our pets, and they tend to correspond accordingly. Learn the science behind about common funny and weird dog behavior.     Understanding the behavior of our dog is essential to training. Knowing their body language, gestures, and attitudes can help us communicate with them and react accordingly. Some of weird dog behaviors may be funny — however, some behaviors can hide their pain or discomfort. Let's dig deep to discover the reasons behind all those nutty behaviors, supported by science. 1. Why does my dog eat grass? Let's start this off easy. "Why do dogs eat grass?" is probably the most often question asked about weird dog behavior. Fortunately, it's extremely common and for the most part harmless. Some dogs complement their diet with the nutrients which are contained in plants while others happily munch on the grass as they love the taste. However, most of the time dogs eat leafy greens to help with an upset stomach; however, if this is repeated often, then it's time to visit your veterinarian. Generally, the only concern may be if the plants have been treated with pesticides, fertilizers or other chemicals.   2. Why does my dog spin around before laying down?     We've all seen it in cartoons, movies or in your own home. Dogs walk in a circle two or three times, scratch a little, and lie down. Of course, your dog is trying to make his or her space as comfortable as possible, similar to how you may fluff a pillow. But why do they all act the same way? Wolves perform the same 360 degree turns to, in addition to seeking comfort, ensure that there is no danger in any direction.   3. Why does my dog eat poop? The scientific name given to this super gross habit is coprophagia. The word is derived from the Greek κόπρος copros, "feces" and φαγεῖν phagein, "to eat". Coprophagy refers to many kinds of feces-eating, including eating feces of other species (heterospecifics), of other dogs (allocoprophagy), or one's own poops (autocoprophagy). Yum! Stool eating has both behavioral and physiological reasons; science says that eating fecal dropping is a normal way of obtaining key nutrients due to deficiencies. However, there's often more to it. On the most simplistic end of the poop eating spectrum, your dog may smell certain scents