Instruct: Given a question, retrieve documents that can help answer the question.
Query: How long can a human survive without water?
A human being can survive an average of three to five days without the intake of water. The issues presented by the need for water dictate that unnecessary water loss by perspiration be avoided in survival situations. The need for water increases with exercise.
Drinking water, also known as potable water, is water that is safe to drink or to use for food preparation. The amount of drinking water required varies. It depends on physical activity, age, health issues, and environmental conditions. Americans, on average, drink one litre of water a day and 95% drink less than three litres per day. For those who work in a hot climate, up to 16 litres a day may be required. Water is essential for life.
Typically in developed countries, tap water meets drinking water quality standards, even though only a small proportion is actually consumed or used in food preparation. Other typical uses include washing, toilets, and irrigation. Greywater may also be used for toilets or irrigation. Its use for irrigation however may be associated with risks. Water may also be unacceptable due to levels of toxins or suspended solids.
Globally, by 2015, 89% of people had access to water from a source that is suitable for drinking – called "improved water source". In Sub-Saharan Africa, access to potable water ranged from 40% to 80% of the population. Nearly 4.2 billion people worldwide had access to tap water, while another 2.4 billion had access to wells or public taps. The World Health Organization considers access to safe drinking-water a basic human right.
"S. corneum" are sensitive to high pollution levels, particularly organic pollutants which foul the water, preventing the clams from effective feeding. As such, they are a bioindicator species whose presence may demonstrate that the water is relatively unpolluted. They are tolerant of anoxic locations however and can survive up to 400 days at and 9 days at without oxygen. This allows them to burrow down into sand, mud, gravel and other inorganic substrates where oxygen levels are low to avoid predation and to explore other food sources. Their anoxic tolerance also allows them to survive at times where low water levels lead to a quick depletion of oxygen, but as they are sensitive to desiccation, or drying out, they cannot survive for extended periods without water.
The common ostrich is a xeric animal, due to the fact that it lives in habitats that are both dry and hot. Water is scarce in dry and hot environment, and this poses a challenge to the ostrich's water consumption. Also the ostrich is a ground bird and cannot fly to find water sources, which poses a further challenge. Because of their size, common ostriches cannot easily escape the heat of their environment; however, they dehydrate less than their small bird counterparts because of their small surface area to volume ratio. Hot, arid habitats pose osmotic stress, such as dehydration, which triggers the common ostrich’s homeostatic response to osmoregulate.
As of , the oldest known living person is Kane Tanaka of Japan, aged . The oldest known living man is Gustav Gerneth of Germany, aged . Due to differences in life expectancy, the 100 oldest women have lived significantly longer than the 100 oldest men.
During the winter and early spring, horses lose about 30% of their body weight. They must regain this weight during summer and fall so as to survive another year. During particularly hard winters ("zuds"), horses may starve to death en masse or die of exposure. Herdsmen can do little to save their herds in such conditions. In the bitter winter of 2009 - 2010, 188,270 Mongol horses perished. Despite their life in semi-feral conditions, most horses live to be 20 – 40 years old.
Carbohydrates are a common source of energy in living organisms; however, no single carbohydrate is an essential nutrient in humans. Humans are able to obtain all of their energy requirement from protein and fats, though the potential for some negative health effects of extreme carbohydrate restriction remains, as the issue has not been studied extensively yet. However, in the case of dietary fiber – indigestible carbohydrates which are not a source of energy – inadequate intake can lead to significant increases in mortality.
Humans evolved to live as simple hunter-gatherers in small tribal bands. Contemporary humans now have a very different environment and way of life. This change makes present humans vulnerable to a number of health problems, termed "diseases of civilization" and "diseases of affluence". Stone-age humans evolved to live off the land, taking advantage of the resources that were readily available to them. Evolution is slow, and the rapid change from stone-age environments and practices to the world of today is problematic because we are still adapted to stone-age circumstances that no longer apply. This misfit has serious implications for our health. "Modern environments may cause many diseases such as deficiency syndromes like scurvy and rickets".)
Humans typically consume less than 100 micrograms of iodine per day. Iodine deficiency can cause intellectual disability. Organoiodine compounds occur in humans in some of the glands, especially the thyroid gland, as well as the stomach, epidermis, and immune system. Foods containing iodine include cod, oysters, shrimp, herring, lobsters, sunflower seeds, seaweed, and mushrooms. However, iodine is not known to have a biological role in plants. There are typically 0.06 milligrams per liter of iodine in human blood, 300 parts per billion of iodine in human bones, and 50 to 700 parts per billion of iodine in human tissue. There are 10 to 20 milligrams of iodine in a typical 70-kilogram human.
The length of the small intestine can vary greatly, from as short as to as long as , also depending on the measuring technique used. The typical length in a living person is 3m-5m. The length depends both on how tall the person is and how the length is measured. Taller people generally have a longer small intestine and measurements are generally longer after death and when the bowel is empty.
Adults are primarily found in estuaries and marine waters to a depth of , but mostly less than . Nevertheless, the species does appear to have a greater affinity for freshwater habitats than the smalltooth sawfish ("P. pectinata"), green sawfish ("P. zijsron"), and dwarf sawfish ("P. clavata"). Largetooth sawfish from the population in Lake Nicaragua appear to spend most, if not all, of their life in freshwater, but tagging surveys indicate that at least some do move between this lake and the sea. Captive studies show that this euryhaline species can thrive long-term in both salt and freshwater, regardless of its age, and that an acclimation from salt to freshwater is faster than the opposite. In captivity they are known to be agile (even swimming backwards), have an unusual ability to "climb" with the use of the pectoral fins and they can jump far out of the water; a individual jumped to a height of . It has been suggested that this may be adaptions for traversing medium-sized waterfalls and rapids when moving upriver. They are generally found in areas with a bottom consisting of sand, mud or silt. The preferred water temperature is between , and or colder is lethal.
The African bush elephant is the largest and heaviest land animal on Earth, being up to tall at the shoulder and in weight (a male shot in 1974, near Mucusso, southern Angola). On average, males are about tall at the shoulder and in weight, while females are much smaller at about tall at the shoulder and in weight. Elephants attain their maximum stature when they complete the fusion of long-bone epiphyses, occurring in males around the age of 40 and females around the age of 25. Their large size means that they must consume around 50 gallons of water every day in order to stay hydrated.
Water has been detected in interstellar clouds within our galaxy, the Milky Way. Water probably exists in abundance in other galaxies, too, because its components, hydrogen and oxygen, are among the most abundant elements in the universe. Based on models of the formation and evolution of the Solar System and that of other star systems, most other planetary systems are likely to have similar ingredients.
Based on the New York Times best-selling book Ice Bound: A Doctor's Incredible Battle for Survival at the South Pole, the movie tells the story of how, in 1999, 46-year-old physician Nielsen decides to leave Ohio and spend a year at the Amundsen-Scott South Pole Station on Antarctica, one of the most remote and perilous places on Earth. Conditions at the station will be far from manageable, with winter temperatures as low as 100 degrees below zero. Joining a team of researchers, construction workers and support staff, Dr. Nielsen is solely responsible for the mental and physical health of all fellow inhabitants stranded at the station through the winter. During the long Antarctic winter, Dr. Nielsen discovers a lump in her breast and is forced to self-administer a biopsy. Communicating via e-mail with doctors in the United States, she learns that the cancer is aggressive and rapid-growing. In order for her to survive several months until conditions will allow planes to land and rescue her from the continent, the doctors concur that she will need to begin chemotherapy treatments immediately.
200,000 years ago, "Homo sapiens" evolves in East Africa. At the time, "Homo sapiens" was one of many human species, such as Neanderthals. Since 13,000 years ago, "Homo sapiens" has been the only surviving human species. Harari suggests that one of the key reasons why Sapiens is able to take control of the world is Sapiens' advanced language.
In the second half of the epic, distress over Enkidu's death causes Gilgamesh to undertake a long and perilous journey to discover the secret of eternal life. He eventually learns that "Life, which you look for, you will never find. For when the gods created man, they let death be his share, and life withheld in their own hands". However, because of his great building projects, his account of Siduri's advice, and what the immortal man Utnapishtim told him about the Great Flood, Gilgamesh's fame survived well after his death with expanding interest in the "Gilgamesh" story which has been translated into many languages and is featured in works of popular fiction.
Some wildlife centers housing captive wolves prohibit handlers from entering wolf enclosures if they happen to have a cold or other vulnerability which the wolves can detect. Captive wolves are generally shy and avoid eye contact with humans other than their owner, as well as not listening to any commands made by any other humans. They usually vacate rooms or hide when a new person enters the establishment. Even seemingly friendly wolves need to be treated with caution, as captive wolves tend to view and treat people as other wolves, and will thus bite or dominate people in the same situation in which they would other wolves. Ordinary pet food is inadequate, as an adult wolf needs 1–2.5 kg (2–5 lbs) of meat daily along with bones, skin and fur to meet its nutritional requirements. Wolves may defend their food against people, and react violently to people trying to remove it. The exercise needs of a wolf exceed the average dog's demand. Because of this, captive wolves typically do not cope well in urban areas. Due to their talent at observational learning, adult captive wolves can quickly work out how to escape confinement, and require constant reinforcement by caretakers or owners, which makes raising wolves difficult for people who raise their pets in an even, rather than subordinate, environment.
Unlike kangaroos and eucalyptus-eating possums, koalas are hindgut fermenters, and their digestive retention can last for up to 100 hours in the wild, or up to 200 hours in captivity. This is made possible by the extraordinary length of their caecum— long and in diameter—the largest proportionally of any animal. Koalas can select which food particles to retain for longer fermentation and which to pass through. Large particles typically pass through more quickly, as they would take more time to digest. While the hindgut is proportionally larger in the koala than in other herbivores, only 10% of the animal's energy is obtained from fermentation. Since the koala gains a low amount of energy from its diet, its metabolic rate is half that of a typical mammal, although this can vary between seasons and sexes. The koala conserves water by passing relatively dry faecal pellets high in undigested fibre, and by storing water in the caecum.
Blue wildebeest are mainly found in short-grass plains bordering bush-covered acacia savannas in southern and eastern Africa, thriving in areas that are neither too wet nor too arid. They can be found in habitats that vary from overgrazed areas with dense bush to open woodland floodplains. Trees such as "Brachystegia" and "Combretum" spp. are common in these areas. Blue wildebeest can tolerate arid regions as long as a potable water supply is available, normally within about distance. The southern limit of the blue wildebeest stops at the Orange River, while the western limit is bounded by Lake Victoria and Mount Kenya. The range does not include montane or temperate grasslands. These wildebeest are rarely found at altitudes over . With the exception of a small population of Cookson's wildebeest that occurs in the Luangwa Valley (Zambia), the wildebeest is absent in the wetter parts of the southern savanna country, and particularly is not present in miombo woodlands.
Depending on breed, management and environment, the modern domestic horse has a life expectancy of 25 to 30 years. Uncommonly, a few animals live into their 40s and, occasionally, beyond. The oldest verifiable record was "Old Billy", a 19th-century horse that lived to the age of 62. In modern times, Sugar Puff, who had been listed in "Guinness World Records" as the world's oldest living pony, died in 2007 at age 56.
When newts are inactive or in oxygen-rich environments, respiration can be done through their skin which accounts for 74% of the cutaneous respiration. However, oxygen-poor environments, such as stagnant ponds, pose a threat to the survival of larval newts. This is because oxygen molecules do not readily dissolve in water, and as "T. carnifex" is an immobile animal, extracting oxygen from water is difficult. Newts consequently have external gills at birth that persist until metamorphosis, which assists survival in low-oxygen conditions.
Tortoises acquire most of their moisture from the dew and sap in vegetation (particularly the "Opuntia" cactus); therefore, they can survive longer than 6 months without water. They can endure up to a year when deprived of all food and water, surviving by breaking down their body fat to produce water as a byproduct. Tortoises also have very slow metabolisms. When thirsty, they may drink large quantities of water very quickly, storing it in their bladders and the "root of the neck" (the pericardium), both of which served to make them useful water sources on ships. On arid islands, tortoises lick morning dew from boulders, and the repeated action over many generations has formed half-sphere depressions in the rock.
Regardless of origin, climate and culture ultimately created the Arabian. The desert environment required a domesticated horse to cooperate with humans to survive; humans were the only providers of food and water in certain areas, and even hardy Arabian horses needed far more water than camels in order to survive (most horses can only live about 72 hours without water). Where there was no pasture or water, the Bedouin fed their horses dates and camel's milk. The desert horse needed the ability to thrive on very little food, and to have anatomical traits to compensate for life in a dry climate with wide temperature extremes from day to night. Weak individuals were weeded out of the breeding pool, and the animals that remained were also honed by centuries of human warfare.
Mudsnails are impressively resilient. A snail can live for 24 hours without water. They can however survive for up to 50 days on a damp surface, giving them ample time to be transferred from one body of water to another on fishing gear. The snails may even survive passing through the digestive systems of fish and birds.
"Giardia lamblia" cysts usually do not tolerate freezing although some cysts can survive a single freeze-thaw cycle. Cysts can remain viable for nearly three months in river water when the temperature is 10 °C and about one month at 15–20 °C in lake water. "Cryptosporidium" may survive in cold waters (4 °C) for up to 18 months, and can even withstand freezing, although its viability is thereby greatly reduced. Many other varieties of diarrhea-causing organisms, including "Shigella" and "Salmonella typhi", and hepatitis A virus, can survive freezing for weeks to months. Virologists believe all surface water in the United States and Canada has the potential to contain human viruses, which cause a wide range of illnesses including diarrhea, polio and meningitis.