NZ Newswire September 12, 2011
The emperor penguin Happy Feet was heading roughly homeward when the transmitter stopped working.
The Our Far South website, where people have been able to see his progress, reported the problem on Monday.
The website says the most likely scenario is the transmitter has fallen off.
It was only glued on and would have had to survive extreme conditions.
It could have also been damaged or suffered a technical fault, the website said.
The transmitter may start working again and it would be a couple of days before it would be known for sure.
"But if we don't get further readings then we'll have to hope for the best and be thankful that we've had such a wonderful cause to raise people's awareness of the Far South," the website says.
The penguin became an international celebrity after he washed up on a beach north of Wellington in June.
He was taken to Wellington Zoo where he had several procedures to remove sand and sticks from his stomach.
Experts believe he ate it thinking it was snow to keep him cool.
Thousands of fans worldwide followed his every move on the zoo's website and on Facebook.
He made a full recovery and was released into the ocean from a fishing boat on September 4, with the tracker attached.
Zoo staff had hoped it would stay on until he moulted next year.