Putin drew worldwide publicity in 2008 when he shot the five-year-old female with a tranquilizer gun and helped place a transmitter around her neck. Visitors to his website could follow the animal's prowlings through Russia's wild Far East. A video of the episode is on YouTube.
Dramatising the plight of a species some conservationists fear may be approaching extinction, Vladimir Krever of the World Wildlife Fund said on Wednesday that the satellite tracking device has been silent since mid-September, which he said could be due to battery failure, a broken collar or poachers.
Hours later, Putin's spokesman Dmitry Peskov, said the batteries on the collar had indeed been running down and wildlife scientists placed a new collar on the tiger a week or so ago.
"She is alive and well," Peskov told The Associated Press.
He said the tiger had given birth to a cub - also fitted with a collar during the most recent encounter - but he did not know when the cub was born.
It was not clear whether the tigers had been spotted since the collars were changed. Peskov said the communications system was being adjusted to enable constant tracking, state-run news agencies ITAR-Tass and RIA-Novosti reported.
Krever could not be reached for comment after Peskov spoke.
Tigers are rapidly disappearing from the far-eastern regions of Russian due to poaching and the loss of habitat, conservationists say.
Their number may have declined by 40% since 1997, the Wildlife Conservation Society said in a report released on Tuesday, although the World Wildlife Fund, disputed that the drop was so large.
The New-York based Wildlife Conservation Society said only 56 tigers have been spotted in an area of 9,000 square miles (24,000 square kilometers) - about one-sixth of their known habitat in Russia. Based on that, the group estimates the total number remaining in the wild at 300.
An estimate in 2005 put the number at 500.
"The sobering results are a wake-up call that current conservation efforts are not going far enough to protect Siberian tigers," Dr. Dale Miquelle of the group's Russian Far East Program said in a statement.
The society recommends a greater effort to preserve the tiger's habitat, stronger legal protections and a crackdown on poachers who hunt the animals for hides and bones prized in traditional Chinese medicine.
Krever said deep snow in the last two years limited the tigers' ability to roam, making it harder to count them. His group agreed, however, that the tigers face a loss of habitat.
Sergei Aramilev, of Russia's World Wildlife Fund, said Chinese poachers have begun attaching explosives covered with animal fat to tree branches. When tigers and endangered Amur leopards swallow the bait, he said, it explodes in their mouths.
The World Wildlife Fund's Russian branch has estimated that 30 to 50 Amur tigers are killed every year.
Illegal deforestation in Russia's Far East and corruption among poorly paid park rangers may also be contributing to the tigers' decline, said Sergei Berezniuk of the Fenix Fund, an environmental group in the Pacific coast city of Vladivostok.
Weighing up to 600 pounds (272 kilograms), Siberian tigers - also known as Ussuri, Amur or Manchurian tigers - prey on wild boars, deer and bears.
They once roamed most of Eurasia from the Black Sea to Central Asia, but now are limited to the forests of Russia's Far East and the Chinese province of Manchuria. In China the killing of a Siberian tiger is punishable by death.
