BEIJING — Virile, canny and possessed with a boundless appetite for red meat, Kuzya, a 23-month-old Siberian tiger, would seem the perfect mascot for President Vladimir V. Putin of Russia, who had a personal hand in reintroducing Kuzya to the wild in the Russian Far East in May.  It turns out that Kuzya, like Mr. Putin, has territorial ambitions, which this week drew him across the frigid Amur River that separates Russia and China. His arrival set off a diplomatic incident of sorts when it became clear that “President Putin’s tiger,” as one Russian newspaper put it, was facing possible peril on the Chinese side of the border.  On Friday, wildlife officials in China’s far northeast were scrambling to ascertain Kuzya’s whereabouts after his Russian minders, tracking him by radio transmitter, expressed concern that he could end up in the hands of poachers — not an unlikely outcome given the steep price a rare Siberian tiger can fetch on the Chinese black market.  “There is still hope that Kuzya will be sensible and swim back before the river turns to icy slush,” the newspaper Novaya Gazeta wrote this week.  Despite a spotty record of environmental stewardship, China holds animals in high regard, both as talismans of good fortune and as ambassadors for global diplomacy (see giant panda).  Mr. Putin, too, has a soft spot for animals, and he is frequently photographed with various wild beasts, including snow leopards, polar bears and dolphins.  In one of his more notable animal-related photo ops, Mr. Putin, wearing white coveralls, strapped himself into a motorized hang glider in a failed attempt to lead a flock of endangered white Siberian cranes on a cross-country migration.  Given the increasingly close relations between Moscow and Beijing, united against what both countries see as a growing challenge from the West, it appears Chinese officials are taking no chances with Kuzya’s safety.  On Friday, the Chinese Foreign Ministry said prodigious efforts were being made to track and protect the tiger, which swam across the Amur on Tuesday after trekking about 300 miles from the spot where Mr. Putin presided over his release.  “We will make joint efforts with the Russian side to carry out protection of wild Siberian tigers which travel back and forth between China and Russia,” Hong Lei, a ministry spokesman, said in a statement.  The incident produced inevitable snickers, with some people in China warning that Kuzya might be a spy, while some Russians suggested that he was seeking to escape Mr. Putin’s authoritarian grip. “Putin’s Tiger Cub Defects — to China,” read the headline in the British tabloid The Daily Mail.  In China, many microblog users predicted an unhappy ending. “How long before this poor tiger becomes a rug in some rich official’s house?” someone posted.  Even with stepped-up enforcement on both sides of the border, wildlife advocates say about 40 tigers are illegally hunted each year. They feed China’s growing appetite for the tiger parts that are used in traditional Chinese medicine and tiger bone wine.  At $10,000 a carcass, the incentive for poachers is hard to resist.  Once abundant across the boreal forests of east Asia’s taiga but hunted to the brink of extinction, the Siberian tiger has made something of a comeback in recent years. That is partly because of efforts by the Russian government to combat the illegal logging and poaching that had reduced their numbers.  The tiger recovery effort has been one of Mr. Putin’s pet projects.  Wildlife officials say there are 370 to 450 Siberian tigers roaming the Russian Far East, up from 40 in the 1940s. Things are not as rosy on the Chinese side.  Fewer than two dozen tigers remain in China. Officials have made progress in recent years by setting aside vast tracts of potential tiger habitat, dismantling the snare traps set by Chinese villagers and imposing fines and significant jail time on those found trafficking in tiger parts.  “It’s an uphill battle, but things are getting better,” said Li Qian, who runs the Asian Big Cats program for the World Wildlife Fund in Jilin Province, China.  On Thursday, officials with the Luobei County Forestry Bureau in Heilongjiang Province said they were installing 60 infrared cameras and sending workers to find the illegal traps that local villagers often set to catch an assortment of wildlife.  Chen Zhigang, the county’s forestry chief, said the government was also prepared to release cattle to supplement a tiger’s normal diet of red deer and wild boar, which are in short supply in China’s heavily populated northeast.  Officials were also working to assuage the fears of local residents “because there has never been a wild tiger in the reserve before,” he said, according to the China News Service.  On Friday evening, the state-run Xinhua news agency reported that another one of the tigers Mr. Putin set free in May, a female named Ilona, was just a few miles from the Chinese-Russian border.  Maria Vorontsova, director of the International Fund for Animal Welfare, in Russia, is following the events closely. Ms. Vorontsova was part of the team that rescued Kuzya and four siblings who were orphaned after a poacher killed their mother nearly two years ago.  “Five tigers represent more than 1 percent of the existing population, so it’s important they survive,” she said by phone.  After spending nearly a year in an enclosure, three of the tigers were released in May in a nature preserve in Russia’s Amur Region. It was Mr. Putin, Ms. Vorontsova noted, who pulled the rope that set Kuzya free.  (She said she knew Kuzya was a fighter when, moments before dashing into the woods, he took a gratuitous swipe at the camera recording his release.)  While some of his siblings stayed in the vicinity, Kuzya was apparently taken with wanderlust and zigzagged through a sparsely settled region of Russia along the northeastern border of Heilongjiang, safely crossing highways and railroad tracks on his way to China. Wildlife rangers who have been tracking his movements by satellite said he was eating well and avoiding human activity, the key to a rehabilitated tiger’s survival.  Asked whether she thought Kuzya was looking to make some sort of political statement by sneaking into China, Ms. Vorontsova laughed.  “Every animal wants a good habitat with enough prey and the possibility to meet a nice female,” she said. “In the meantime, hopefully he won’t get into any trouble.”  Kiki Zhao and Bree Feng contributed research from Beijing, and Nikolay Khalip from Moscow.  A version of this article appears in print on October 11, 2014, on page A1 of the New York edition with the headline: Putin’s Tiger,’ in a Territory Grab All His Own, Swims to China. Order Reprints|Today's Paper|Subscribe
A Siberian tiger released into the wild in Russia in the spring crossed a river this week into China, where wildlife officials are tracking his whereabouts.