Bile bear
A bile bear or battery bear is the term used for Asiatic black bears kept in captivity in Vietnam and China so that bile may be extracted from them for sale as a traditional Chinese medicine (TCM). The bears are also known as moon bears because of the cream-colored crescent moon shape on their chest.  The Asiatic black bear, the one most commonly used on bear farms, is an endangered species.

# Living conditions
The bears live in extraction cages, also known as crush cages, which are little bigger than themselves for ease of "milking." Bears may live as long as twenty-five years in these cages with the confinement causing mental stress as well as severe muscle atrophy. Their bile is extracted through a bile fistula, a tube that is surgically inserted through the abdominal wall and into the gall bladder, where bile is stored after being secreted by the liver via the hepatic duct. This bile fistula is connected to a collection system. Between 10 and 20 ml of bile is tapped from each bear twice daily. The WSPA reports that, during milking, investigators saw bears moaning, banging their heads against their cages, and chewing their own paws. The mortality rate is between 50 and 60 percent. Bears in bile farms suffer from a variety of physical problems which include loss of hair, malnutrition, stunted growth, muscle mass loss and often have teeth and claws extracted. When the bears stop producing bile after a few years, they are usually killed for their meat, fur, paws and gall bladders. Bear paws are considered a delicacy.

# Numbers
There are estimated to be around 4,000 bile bears in Vietnam, where their bile can sell for 100,000 dong (~ US$6.25) a millilitre (with 37,500 dong a week regarded as the poverty line for an urban resident), and around 9,000 bile bears in China. The World Society for the Protection of Animals (WSPA) conducted a study in 1999 and 2000, and estimates that there are 247 bile-bear farms in China, holding 7,002 bears, 
 though the Chinese government has called the figures "pure speculation." 
In July 2000, Animals Asia Foundation, a Hong-Kong based charity set up by Jill Robinson MBE,  signed an agreement with the Chinese government to rescue 500 suffering and endangered Moon Bears from the worst bile farms in Sichuan province, and work towards ending the practice. Today, the China Bear Rescue has seen freedom for 219 previously farmed Moon Bears at a Sanctuary in Chengdu, and is helping to advance the concept of animal welfare in China.
The Chinese consider bear farms a way to reduce the demand on the wild bear population.  Officially 7,600 captive bears are farmed in China. According to Chinese officials, 10,000 wild bears would need to be killed each year to produce as much bile. The government sees farming as a reasonable answer to the loss of wild bears from poaching, and at the same time claim insouciance regarding the cruelty issues that concern Western animal rights activists.  However, the government's agreement with Animals Asia Foundation to allow the rescue of 500 bears from farms may represent a softening of the government's tough stance on bear suffering. 

# Bile trade
The monetary value of the bile comes from the traditional prescription of bear bile by doctors practising traditional Chinese medicine. Bear bile contains ursodeoxycholic acid (UDCA), which is believed to reduce fever, protect the liver, improve eyesight, break down gallstones, and act as an anti-inflammatory. The high demand for the bile has led to the introduction of intensive farming of bears. Because only minute amounts are used in traditional Chinese medicine, a total of 500 kg of bear bile is used by practitioners every year, but according to WSPA more than 7,000 kg is being produced, most of it being used in wines, eyedrops, and general tonics.
In January 2006, the Chinese State Council Information Office held a press conference in Beijing, during which the government said that it was enforcing a "Technical Code of Practice for Raising Black Bears," which "requires hygienic, painless practice for gall extraction and make strict regulations on the techniques and conditions for nursing, exercise and propagation."  However, a 2007 Veterinary Report published by the Animals Asia Foundation stated that the Technical Code was not being enforced and that many bears were still spending their entire lives in small extraction cages without free access to food or water. AAF also noted that the free-dripping technique promoted in the Technical Code was unsanitary as the fistula created to access the gall bladder allowed for an open portal through which bacteria could infiltrate the abdomen. The AAF Vet Report also stated that surgeries to create free-dripping fistulas caused bears great suffering as they were performed without appropriate antibiotics or pain management and the bears were repeatedly exposed to this process as the fistulas often healed over. The free-dripping method still requires the bears to be prodded with a metal rod when the wound heals over and, under veterinary examination, some bears with free-dripping fistulas were actually found to have clear perspex catheters permanently implanted into their gall bladders. In addition to the suffering caused by infection and pain at the incision site, 28% of fistulated bears also experience abdominal hernias and more than a third eventually succumb to liver cancer, believed to be associated with the bile-extraction process.

# Pharmacology
The active therapeutic substance in bear bile--and in the bile of all mammals--is ursodeoxycholic acid (UDCA). This acid has been recognized by both Asian and Western physicians for at least 40 years to have benefits for patients with diseases of the liver and biliary system. Before the manufacture of UDCA by pharmaceutical companies, bear bile was prescribed by practitioners of traditional Chinese medicine because it contained a higher percentage of UDCA than the bile of other mammals. However, modern chemistry has made this fact irrelevant. Today, pharmaceutical-grade UDCA is now collected from slaughter houses, then purified and packaged under trade names such as Ursofalk, Actigall, and UrsoForte. These products are approved by the Federal Drug Administration (FDA). Substances in mammalian bile other than UDCA, such as cholesterol, have never been demonstrated to have any healing effect in humans. Despite this observation and the availability of affordable pharmaceutical-grade UDCA, some practitioners of traditional Chinese medicine continue to prescribe whole bear bile for their patients and reject any sort of modern substitute. These individuals drive the market demand for bear bile and pressure the Chinese government to continue the practice of bear farming.

# Notes
-  Asiatic black bear
-  U.S. Embassy of China: "Bile Bear Report."
-  Morality rate
-  Parry-Jones, Rob & Vincent, Amanda. "Can we tame wild medicine?", New Scientist, vol 157 issue 2115, January 3, 1998, page 26.