Sentinel species

Many observations of animals point to toxicity in food, water or air that would or could harm humans. Canaries The classic example is the "". The idea of placing a warm-blooded animal in a mine to detect carbon monoxide was first proposed by John Scott Haldane in 1895, and canaries were used as early as 1896. Countries such as Britain, the United States, and Canada used canaries as a sentinel species. Well into the 20th century, coal miners brought canaries into coal mines as an early-warning signal for toxic gases, primarily carbon monoxide. The birds, being more sensitive, would become sick before the miners, who would then have a chance to escape or put on protective respirators. In some cases, the canaries were kept in cages with dedicated oxygen tanks so the birds could survive after their illness provided a warning. "Canary in the coal mine" is now used as an idiom for a person or thing that warns people of danger. Cats In Minamata Bay, Japan, cats developed "dancing cat fever" before humans were affected due to eating mercury-contaminated fish. Dogs Dogs were recognized as early as 1939 to be more susceptible to tonsil cancer if they were kept in crowded urban environments. Mussels In Poznań, Poland, eight mussels equipped with sensors are used to ensure the safety of the city's drinking water. These mussels act as bioindicators, meaning they provide a reliable estimation of water toxicity by responding to changes in water quality. == Characteristics ==

Animal sentinels must have measurable responses to the hazard in question, whether that is due to the animal's death, disappearance, or some other determinable aspect. == Specific applications ==

Toxic gases Canaries were iconically used in coal mines to detect the presence of carbon monoxide. The bird's rapid breathing rate, small size, and high metabolism, compared to the miners, led birds in dangerous mines to succumb before the miners, thereby giving the miners time to take action. Air and water pollution A number of animals have been used to measure varying kinds of air pollution. These include honey bees for air pollution, bivalve molluscs for online water-quality survey and pigeons for atmospheric lead. Scientists also monitor crayfish in the wild in natural bodies of water to study the levels of pollutants there. The Protivin brewery in the Czech Republic uses crayfish outfitted with sensors to detect any changes in their bodies or pulse activity in order to monitor the purity of the water used in their product. The creatures are kept in a fish tank that is fed with the same local natural source water used in their brewing. If three or more of the crayfish have changes to their pulses, employees know there is a change in the water and examine the parameters. Infectious diseases The discovery of West Nile virus in the Western Hemisphere was heralded by an outbreak of disease in crows and other wild birds. Other emerging diseases have demonstrated linkages between animal health events and human risk, including monkeypox, SARS, and avian influenza. In outbreaks of bubonic plague, rats begin dying out before humans. Household toxins Dogs may provide early warning of lead poisoning hazards in a home, and certain cancers in dogs and cats have been linked to household exposures to pesticides, cigarette smoke, and other carcinogens. ==Cultural references==

• Kurt Vonnegut in an interview compared the function of artists in human society to coal-mine canaries; see Wikiquote. • "Canary in a Coalmine" is the title of a non-single track on The Police's 1980 album Zenyatta Mondatta. • "Canary in a Coalmine" is the title of a non-single track on The Crane Wives' 2012 album The Fool in Her Wedding Gown • American professional baseball league Charleston Dirty Birds are named for canaries in coal mines. • Name of the Canary Complex music project is a reference to "canary in the coal mine". == See also ==