According to Spiegel Online, Knut suddenly collapsed and died in the water area of the polar bear enclosure as 600-700 visitors to the zoo watched. Knut was hand-raised by zookeepers after his mother rejected him at birth, and the keeper pictured with him, Thomas Doerflein, passed away of a heart attack in 2008 at the age of 44. Read the full Spiegel story here, and read more about Doerflein here. See more images from Knut's life here.

Herbert Knosowski / AP file
Knut, the polar bear cub, has its first public appearance with his keeper Thomas Doerflein in the Berlin zoo on March 23, 2007. A Berlin zoo official says world-famous polar bear Knut has died. Bear keeper Heiner Kloes said that four-year-old Knut died Saturday, March 19, 2011 while alone in his compound. He says the cause is not yet clear.


My wife and I saw Knut this past summer when we were traveling in Germany; my wife loves bears, and it was a complete thrill for us to see him. Our heartfelt sympathies to his keepers who I'm sure will miss him terribly.
He died of a broken heart for Thomas.
I thought that too! So sad! I hope they are playing together now!
Yes
I was so saddened by reading about the untimely death of little Knut.....surely he was lonely for his keeper Thomas and died of a broken heart. Animals ,it has been proven have deep connections to THEIR PERSON and mourn.........we will all miss hearing about him. My sympathies to everyone who knew and loved him.
How traumatic for those who saw this happen. About nine years ago at a zoo in a western state (don't want to mention the zoo)...a female tiger was killed by a male tiger in front of some visitors...they had been paired up as a couple, and had been in a remote area of the zoo for about a month. They had been moved to the public viewing area just earlier that week.
We'll miss the updates on Knute's life...and the smiles he was always able to bring to us...
I have always followed little Knut on youtube and the news. My heart weighs heavy today because of this loss. Yes, animals do die of broken hearts and I am afraid that this was it. Our polar bears were moved away until their new zoo habitat could be complete and to see such beauty is beyond measure. Over the rainbridge for little Knut.
I was born in Berlin was there numerus times,and comming to Visit again with my Daughter and Granddaughter, was planing to Visit Knut. Sorry that He Died so young.I have Followed the Story from His Birth.
very sad news, I saw Knut at the Zoologisher Garten in Berlin one year ago, a lovely wild animal, he was moving a lot in his compound and looking at us; I can imagine how horrified visitors were when he dropped dead in his water basin; and what an odyssey for his short life: abandonned by his mother, he developped a very strong bond with Thomas, his keeper, who then commited suicide two years ago and now this early death, very sad
a correction to my comment, Thomas Dörflein Knut's keeper at the Zoologischer Garten didn't commit suicide but instead died of a cancer
So sad Knut died at such a young age ,sounds like he grieved himself to death literally for his trainer Philip may God bless them both.
I'm an animal lover myself, and I feel so awful for the many visitors and keepers. My heart just sank when I heard the news. I've watched videos of Knut, and he was so beautiful inside and out. My thoughts and prayers go out to everyone. I do believe when animals loose a partner, keeper, etc. that it's quite possible of a broken heart, as I've witnessed it myself :( I hope that somewhere in heaven they are together again.
Knut passed away... Very sad news even in Japan. We have gone into shock again.
He met Thomas up there, we are sure. We would like to keep him in mind. May their spirits
rest in peace.
One of our friends in Berlin gave us a stuffed Knut in 2007. We'll keep it.
Thnak you, Knut.
In Tokyo, Japan
Has he met Thomas up there?
Correction: Thnak you, Knut. --- Thank you, Knut. And delete the last line.
Knut...May your journey be gentle. I pray that your spirit will help the Moon Bears in Southeast Asia become free of their tormentors and the Bears of Afghanistan be free of their tormentors and the Bears of the US become free of their tormentors... God Speed and God Bless the beautiful Knut.
Now that their exile on earth has been ended. May Thomas and Knut rest in peace, in the loving arms of our God.
Knut was a stunning animal, he and Thomas were beautiful together. Knut mourned the loss of his friend Thomas, he felt the pain, the howling and plaintive cries after Thomas passed were his only means of expressing this loss. I wish the zoo officials would have acknowledged Knut's pain or even acknowledge animals grieve, they do grieve.
Knut you will be missed but you and Thomas are busy playing in the stars. I smile when I gaze into the stars.
Did anyone read the article. He didn't have a broken heart, he had a swollen brain from an infection. Quit trying to make everything all roses and sugar......
Did you people even read the story. He didn't die of a broken heart, he died of a swollen brain from an infection. I'm sure many are saddened by this death, but the mush on this is a little overboard. "I'm sure he's frolliking in the stars on the wings of angels being cradled by the arms of cosmic love".
I have the book "Knut: How One Little Polar Bear Captivated the World", and I just read it to my grandsons about 2 weeks ago. I was surprised how much the 2nd-grader knew about the endangerment of the polar bears' natural habitat. (The book is one of several by the authors attempting to raise awareness of such environmental issues.) The boys will be very sad to see this article.
im agree with k Starlin,,,,,, k Starlin, i havent read or hear this kind of truth long time ago.. excuse my english, im from Ecuador