DOGS

Barking on command
A dog can be trained to bark when its owner gives a command, such as "Speak." Dogs can also be trained to "say please" -- to bark when presented with a treat.

Playful bark

Some dogs will bark for a treat or when they are playing. Dogs will also bark when they like what they're playing.

Need bark

Many dogs can self-develop actions that serve themselves if they need something. This is commonly done along with a form of action