The poem
His vision, from the constantly passing bars, has grown so weary that it cannot hold anything else. It seems to him there are a thousand bars and behind the bars, no world.
As he paces in cramped circles, over and over, the movement of his powerful soft strides is like a ritual dance around a center in which a mighty will stands paralyzed.
Only at times, the curtain of the pupils lifts, quietly-. An image enters in, rushes down through the tensed, arrested muscles, plunges into the heart and is gone.

They show this poem in Awakening, in a nice exchange between a catatonic Robert DeNiro and the doctor Robin Williams
His poem about the panther is read at a climax juncture in the movie" Awakwnings" where it reveals that a group of human beings are physically, mentally,and spiritually confinded in their wretched bodies , simpatico to the vibrant potential of the panther is trapped by the bars of a cage. These patients in a chronic hospital in the Bronx in the mid to later 60's are restrained , just as the panther is , by a mysterious physiological condition that freezes there speech, fine and gross motor skills, and eventually their will to aspire.
The panther is a translation. That means there are multiple translations. You might have heard a different one, but that doesn't mean this translation is not valid. I agree, however, that this is not my favorite version.
this is my fvorite translation i think the most trusted translation
This version of the Panther is my favorite version based on the very salient imagery and rhythm. Many translations don't actually adhere to a sensuous or poetic tone, one that is to me essential in a Rilke. His poetry in general is androgynous in its illustration, containing both intimidating force and streamlined beauty.
Not to mention that Stephen Mitchell, the translator of this version, is one of the most renowned Rilke translators. For a good reason, which you can detect if you have the eye and ear for it.