java计算时间间隔小时:狗的习性（英文）

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The dog is a pack animal and is therefore sociable and enjoying company. In the wild dogs follow a complex hierarchy within the pack with a pack leader who is a strong and assertive leader. In the absence of a pack the dog views the family with which it lives as its "pack" and it is important that a family member is established as the pack leader during training and that the dog understands that it is ranked lowest within the pack in order to avoid behavioural problems.

Dogs communicate using sound and body language and listed below are the basic ways in which dogs use body language to display their mood.

Happy and Excited

A happy dog has its ears perked forward, a relaxed mouth and wagging tail. If excited the dog may also jump up, circle or run around. This can be accompanied by barking or mock growling.

Invitation to play

When the dog bows down with their front lowered and their rear in the air with tail wagging they are inviting play.

Aggressive

An aggressive dog lays its ears back close to its head and narrows its eyes giving a challenging stare. The mouth may be open or drawn back exposing its teeth and the dog may snap its jaws. This is often accompanied with snarling, growling or loud barking. The body is tense and the tail held straight out from the body and the head lowered.

Dominant

A dominant dog holds its ears upwards or forwards and stares with eyes wide open. The body is carried tall, possibly with hackles raised. The tail is held straight up or out from the body and the dog may growl or grunt from a closed mouth.

Submissive

A submissive dog will roll over onto its back and display its stomach. A contented dog will also display its stomach in this way when it is happy and wants its stomach rubbed.

Fearful or Apprehensive

A dog that is fearful or apprehensive lays its ears close to its head with narrowing eyes. The body is held low and the tail tucked between its back legs. The dog may tremble, yelp, growl or whine.