Remember cuddly Knut, the polar bear whose adorable antics as a fluffy cub melted the hearts of countless live and online visitors to the Berlin Zoo, and whose line of plush stuffed bears, DVDs, squeeze toys, T-shirts, key chains and other trinkets brought in millions of dollars?

     For a while the immature ursine image was ubiquitous – daily webcasts of his fuzzy frolics went viral; he even shared the cover of Rolling Stone magazine with Leonardo DiCaprio in a photograph taken by Annie Leibovitz.

    But then, like so many former child stars, Knut slid from celebrity to surliness. In four short years he transformed from a huggable, snow-white puffball to a menacing, muddy brute – and the zoo, once a savior who took Knut in after his mother rejected him at birth – pondered ways to get rid of him, such as selling the hapless animal to another institution.

     Last week, Knut solved the zoo’s problem.

    You can watch Knut’s pathetic, final starring role on an amateur YouTube video taken by a zoo visitor. It’s not a pretty performance. He circles aimlessly a few times, then stumbles off a rock, topples into a pool and drowns.

      Knut’s ignominious but all-too-depressingly predictable fall from grace represents a perversion of the Circle of Life so often perpetuated in zoos and so-called wildlife rehabilitation centers, which purport to help wild animals but really wind up exploiting them, or worse.

      While speaking to a journalism class at the University of Connecticut in Storrs earlier this week, I mentioned that I planned to write a blog about Knut’s sad saga, and one student asked if zoo breeding programs designed to preserve and propagate endangered species ever justified keeping them in captivity.

     It was an excellent question, and I had to give a qualified answer. If zoos truly were in business to serve animals, promoting research that enhanced human appreciation for their existence in the natural world, then I could endorse them. But too often, zoos and similar institutions exploit rather than educate.

      I first wrote about Knut just as he emerged as a media darling four years ago, and noted that ironically, his surge in popularity coincided with Russia’s decision to allow hunters in the remote Arctic settlement of Vankarem to gun down polar bears because a few of the aggressive predators strayed too close to village homes.

     I wrote then, “I’m hard-pressed to say which situation is more disturbing. I guess shooting the beleaguered animals – endangered species, no less – is probably worse than loving them to death, but both extremes illustrate homo sapiens’ often unhealthy relationship with the so-called lower species. For the most part we see wild animals either as threats or as sources of entertainment, so we either kill or cage them – in which case we also anthropomorphize them for fun and profit.”

     Would Knut and the world have been better off if the zoo simply allow him to die after his abandonment?

     To be sure, this happens all the time in the wild – perhaps his mother detected some fatal genetic flaw that caused her to reject her cub – but the zoo couldn’t have allowed that to happen, so it seized on a marketing opportunity that was doomed from the get-go.

     As of this writing authorities are still trying to determine what led to Knut’s early demise – polar bears typically live 10 or 15 years in the wild and up to 30 years in captivity, where they don’t have to worry about seal shortages or melting polar ice.

    As you might imagine, I no longer go to zoos, but I do recall on one of my last visits I watched a polar bear swimming idly in a tiny pool with fake ice while a crowd of gawkers snapped photos.

    I guess that bear was better off than the only other polar bear I saw years earlier on the ice-choked shore of the Arctic Ocean in Barrow, Alaska. An Inupiat Eskimo had just shot it and draped the skin over a line to dry.

   As for Knut, according to some published reports, Berlin Zoo authorities plan to have him stuffed so visitors can continue to pay homage. I’m guessing they also still have a few crates of Knut teddy bears to unload.