In Death Valley Heat, Salt Creek Pupfish Find a Way to Survive

It's springtime, Earth Day, which means that one of nature's weirdest events is in high gear. But you have to take the heat to experience it. And you sort of have to live in a place called Devil's Hole.

That's Devil's Hole in Death Valley, Calif. For starters, it's one of the hottest locations on Earth (summertime average temperatures hover around 115 Fahrenheit, and once reached 134 F).

It features the lowest point in the Western Hemisphere, a golf course that's more than 200 feet below sea level and trees that must extend their roots up to 60 feet down to find water.

For all of its parched, stark beauty, it doesn't sound like an environment that could sustain much of any kind of life, let alone fish life.

But it does, in the form of these strange little swimmers called the Death Valley pupfish.

Thousands of years ago in the Pleistocene era, there were large lakes (including Lake Manly) in Death Valley. As the bodies of water dried up, small streams and pools managed to survive. The pupfish (named for the way they frolic in the water) were trapped in these shrinking pools, selected by evolution to survive and eventually becoming the species we know today.

There are a number of types of pupfish in Death Valley, each stranger and more rare than the next. These species include:

• The Saratoga pupfish, located at the south end of Death Valley.
• The highly endangered Devil's Hole pupfish, found 37 miles east of Furnace Creek, in western Nevada.
• The Cottonball Marsh pupfish, found in Cottonball Marsh on the west side of central Death Valley.
• And the famed Salt Creek pupfish, located in Salt Creek in the central part of Death Valley.

The Salt Creek pupfish have become renowned each spring in Death Valley because they are the easiest to locate, observe and study during their frisky mating season. The male pupfish are easiest to spot because they turn bright blue and put on an aggressive display to drive off potentially rival suitors.

Easily visible for just a few months each year, the inch-long fish can survive in water temperatures that exceed 112 degrees F.

In fact, the tiny fish are so adapted to warm water that they must burrow into the mud and become dormant when the shallow stream becomes cold in the winter. Another hurdle these fish face is high salinity. Pupfish can actually live in water that's up to three times saltier than ocean water.

In the summer, when Salt Creek evaporates, the dissolved salts become even more concentrated. For fish that live in freshwater, it's easy for them to absorb water through their body by osmosis. But pupfish have to drink to get their necessary water, and the excess salts are then excreted through their gills and kidneys.

Pupfish feed on green and brown algae and reach full maturity in two to three months. The average lifespan of a pupfish is six to nine months, although in rare cases some can survive for more than a year.

During the spring mating season, the highly adaptive Salt Creek pupfish are extremely active, thus making them one of the most popular stops for tourists visiting Death Valley. A recently installed boardwalk at Salt Creek makes it easier for the general public and scientists alike to study the quick-darting prehistoric swimmers.

Pupfish are one of the most researched animals in Death Valley and are considered a barometer of the overall health of the Death Valley ecosystem.

And for visitors to Death Valley National Park during spring break, they provide one of the weirdest, great fish stories of all time.

More Earth Day Coverage:

The Earth From Above [PHOTOS]

Earth Day: The Planet's Most Extreme Places [PHOTOS]

Earth Day: Endangered Species [PHOTOS]

Earth Day: A Look Back [PHOTOS]

On Earth Day, Oil Cleanup Continues in the Gulf [PHOTOS]

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