Water is quite precious here in the desert because of its relative scarcity. Tucson only gets about 12 inches (30 cm) of rain per year. Because water is so scarce in the desert, an excellent way to attract a wide variety of wildlife to your yard here is to provide them with a reliable, clean water source. Birds and animals are especially attracted to the sound of moving water, such as from this bubbling fountain.

Fountain water frozen in time

Many desert animals have specialized physiological and behavioral adaptations that allow them to survive with very little water, but they will still happily use any water sources that happen to be available.

Humans, unlike desert animals, require plenty of water here in the desert, especially during our hot summers when dehydration is a serious concern for those engaging in outdoor activities. Dehydration occurs when the body does not have sufficient water and fluids. The symptoms can include dry mouth, dry eyes, no urine or only a little dark urine, lethargy, and even coma or death in extreme cases. Dehydration can also lead to heat exhaustion and heat stroke. The best way to prevent this is to drink plenty of water when out in hot weather… But not too much.

While too little water can cause dehydration, too much water is also quite dangerous and can cause hyponatremia (water intoxication). This can be a problem not only for marathon runners and other long distance athletes, but for anyone engaged in prolonged, strenuous outdoor activities in hot weather.

Sweat is salty because it contains sodium and other salts, and with prolonged heavy sweating, a great deal of sodium and water can be lost from the body. With so much sodium lost, drinking large amounts of water to replace what was lost can then dilute the sodium concentrations in the body to dangerously low levels. The process of osmosis can then cause the cells in the brain to suddenly swell with water as the cells' fluid-filled interiors containing normal, higher sodium concentrations (thus lower water concentrations) equalize with the now dangerously lower sodium concentration (thus higher water concentration) outside of the cells.

This brain swelling, known as cerebral edema, is what makes water intoxication so dangerous, and it can cause nausea, vomiting, tiredness, confusion, seizures, depressed reflexes, Cheyne-Stokes respiration, and even coma or death in severe cases. The best ways to prevent water intoxication during prolonged sweaty activities are to use sports drinks containing electrolytes (sodium) and not drink excessive amounts of water.

Update: A reader with a keen artistic eye has spotted the form of a kissing couple in the water in the above image. Can you see it? The long-haired woman is on the right.