Why is "Chases its tail"?

[Bruno]

Why " Chases its tail"? I didn't understand it
please explain to me!

Bruno

[Alan]

Hi Bruno,

What are you referring to in this:

[spencer]

Hey friend!
I think this sentence is usually used, when somebody makes hard efforts to get something, but always fails.
Im not sure though
Spencer

[Guest]

did you get this sentence from the American Homophones test? where is says the dog chases its tail? If so it means the dog is trying to catch his own tail. Do you know how some dogs play with themselves some time and they start spinning around as if trying to catch their tail. We say that they are chasing their tail.
Hope that answers your question!

[Nicole]

Hi think Spencer is referring to this:
http://www.english-test.net/forum/ftopic6278.html#15827

Nicole
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