As is clear in Life of Pi, surviving for long periods of time at sea is extremely difficult, even without an adult tiger in the mix. Many experts consider survival at sea to be the most difficult survival situation. The three essentials of survival are protection from the elements, food, and water. Pi makes it clear that lack of abundant fresh water was his greatest stress at all times, and this is realistic: Pi was in a fairly hospitable climate and so faced little danger of freezing to death, and humans will die of dehydration long before they die from starvation. In fact, dehydration is such a danger that in a situation without abundant fresh water, survival experts recommend eating nothing rather than eating protein, which requires water from the body’s store to be digested.
In situations like Pi’s, where there is limited protection from the sun, experts recommend wetting skin and clothes with salt water, which helps prevent loss of body water through sweating. They also recommend being as still as possible during the heat of the day, and doing essential activities at dawn and dusk to minimize sweating. Although Pi finds that his seasickness is never as severe as Orange Juice’s or Richard Parker’s, seasickness can be dangerous in trying to survive at sea, for the vomiting it can cause will further dehydration and weakening.
Pi is also correct not to try to survive in the water in order to distance himself from Richard Parker—life expectancy in a survival at sea situation is much worse for those who do not have a boat or raft. Even in the warmest waters, life expectancy is only twelve hours, and it quickly drops the colder the water is.
Drinking seawater and urine are both, Pi is correct to believe, dangerous, and hurry the process of death by dehydration. Even drinking seawater diluted with fresh water is dangerous and not helpful. Pi is also correct that turtle blood is a safe method of hydration, and there is also potable liquid in fish eyes and fish spinal fluid. Although some fish can be poisonous, generally fish that are available when you cannot see land are safe. Solar stills are known to be theoretically helpful, but often do not work well in practice.
The side-effects of dehydration can include headache, irritability, dizziness, faintness, rapid pulse, shallow breathing, pins and needles, and after that, hallucinations and delirium, preceding death. Blindness, however, is not a common side-effect.