The desert pupfish, a fish on the verge of extinction due to the simple misfortune of living in Death Valley, has managed to survive by learning to hold its breath for up to five hours at a time.
Having spent the bulk of its evolutionary history in cool waters, the last 10,000 have been rough on the fish due to the valley’s ever-receding Lake Manley. The limited water and sheer heat have forced them to survive in temperatures as high as 95 degrees fahrenheit – and they’re not exactly flourishing because of it.
The pupfish survive by randomly switching between aerobic and anaerobic breathing techniques – an example of “physiological plasticity”, adjustments organisms are forced to make due to seismic shifts in their environment. Usually, such adaptations result in stunted dietary habits or hibernation, but the desperate pupfish has managed to cease breathing altogether. Unfortunately for the pupfish, life without oxygen takes 15 times the metabolic energy of regular breathing and the fish has a very short life span because of it. But desperate times call for desperate measures, and the pupfish is doing the best he can under the circumstances. Says researcher Frank Van Breukelen of the University of Nevada, “Sometimes organisms have to take the lesser of two evils, but it doesn't necessarily mean this alternative is a great option. We think this process is really tough on the fish.”
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