Wuhan, China (CNN) -- Professor Kou Zhangbing conducts a health check. He tenderly calls the patient over with a tap of his hand, checks tongue and teeth for injuries, eyes for mood, and skin for scratches. As a treat, he hands out a salted fish.
"The most important thing we can do is to keep them healthy," he says.
Kou is one of a handful of Chinese scientists trying to save the finless porpoise, a freshwater species found in the Yangtze River. Rarer than China's giant panda, this famed species now teeters on the brink of extinction.
Recent surveys suggest that there are a mere thousand animals left, down dramatically from similar surveys conducted just six years ago.
"If proper measures aren't taken they will be extinct in 10 years, but to be honest, we only have five years to take action," said Zhang Xinqiao of the World Wildlife Fund.
Professor Kou and his colleagues research the rare mammal in a series of deep blue pools at the Institute for Hydrobiology in Wuhan. They are trying to understand these curious creatures and possibly breed them for the wild.
"I spend more time with them than with my family," said Kou, "They have become an indispensable part of my life."
It's mating season, so they dance underwater and act a little strange. Occasionally, a porpoise swims right up to the viewing glass and all but presses its face against it. The porpoise's face is set in a permanent quizzical smile. Dark and forward-facing eyes carefully monitor the movements of its visitors.
Porpoises are smaller and stouter than their dolphin cousins; they have shorter beaks, and live in smaller groups.
Those groups could be getting even smaller in the wild. Asia's longest river is also one of its most polluted. Scientists estimate that about 800 million tons of wastewater is dumped into the Yangtze every year. Pollution, overfishing, and intensive development on the Yangtze have all combined to push the porpoise near extinction.
"All of these human activities have destroyed the natural habitat of the finless porpoise, taking away their food supply and even injuring and killing them directly," said Zhang.
He said the prospect of survival in the Yangtze is bleak, but he clings onto hope for the species.
That hope, such as there is, can be found West of Wuhan in Tian-e-Zhou oxbow lake. Once part of the Yangtze, the lake was formed from a bend in the river and then separated from the main stream.
"This is the best chance we have to keep the species alive," said Gao Daobin, an official in charge of the park. "We only have this animal in China and kids will start asking questions when they learn about it. They will ask 'why did it go extinct?'"
It's no idle fear. The Baiji dolphin, a regal animal with its trademark pointed beak, went functionally extinct in the Yangtze in 2006. Scientists believe there may be individual animals in the murky water, but it could never sustain the species.
So the finless porpoise is the last remaining freshwater cetacean left in China.
Gao shows us a breeding pen separated from the lake by just a net. A handler drops individual fish into the mouth of the captive porpoises. They have to make sure to give exactly the right nutrients. They will be released into the lake, where the fewer than 40 porpoises could represent their last stand.
"Nobody cared about them in the past, but attitudes are changing. Now, if they go extinct, all of our years of work will be meaningless," said Gao.