Staying Alive

Approximately 65 million years ago, a meteor crashing down to Earth resulted in 80% of all animal species going extinct—a loss so cosmic it’s hard to even fathom. The Cretaceous–Tertiary extinction event is most widely known for wiping out the dinosaurs, but not all ancient reptiles were annihilated. One order in particular has proven especially resilient—and unusual—in its ability to stand the test of time: crocodilians, which includes true crocodiles, alligators, and caymans. These animals have much to teach us about how to survive swimming in strange water.

H.G. Wells once wrote that “Adapt or perish, now as ever, is nature’s inexorable imperative.” And yet, crocodilians have proven to be an exception to this rule. They are among the most resilient animals on Earth, but not because of any extraordinary adaptations or leaps in evolution. Rather, a study published in Nature Communications Biology journal found that a lack of change has actually afforded these reptiles the ability to stay thriving. They found an ideal form that has served them so well that they have hardly had the need to evolve over the millennia. 

So what are the traits that have allowed these creatures to endure across the ages? Well, part of why this form has served crocodilians for so long is because it’s inherently versatile: they are ideally suited for an amphibious lifestyle on both land and water. That’s why the majority of these reptiles make their homes along swampy shores and rivers. A long physique and muscular tail make them excellent swimmers. Meanwhile, nostrils and eyes situated atop the highest parts of their head allow them to see and breathe while mostly submerged—even at night.

Part of crocodilians’ resiliency also resides in their sheer strength; they have one of the strongest bites in the animal kingdom, with powerful jaw muscles that allow them to clamp down with as much as 250,000 pounds of pressure per square inch at the tips of their teeth. This actually exceeds what their teeth are capable of withstanding, which is why they go through so many; beneath each tooth is a column of ones ready to grow in and replace it. Crocodilians may go through as many 3,000 teeth in their lifetime. 

And then there are the mysteries of the blood, which is resilient in its own right. Despite often accruing wounds from war with both prey and predators—including other crocodilians—these reptiles rarely get infections. Research has found that their blood possesses proteins that provide some innate immunity against harmful bacteria, viruses, and fungi, which often run rampant in swampy waters. Its potential for helping humans has been the subject of much medical research, some of which has even found it capable of suppressing HIV.

Of course, a species’ survival also depends on its ability to safeguard the next generation. As for crocodilians, despite being such ferocious predators, most species are also gentle and nurturing with their young. A mother will dig a hole to place her eggs in and keep them warm, standing guard against any potential foe. When they are ready to hatch, her young start to chirp—and she uses her same deadly jaw to delicately help them break through their eggs. She will then care for them for months after they hatch, even keeping them safe by placing them directly in her mouth.

Over the last few years, I have written odes to evolution and waxed poetic on the importance of adaptation for our survival, which I believe wholeheartedly. At the same time, crocodilians remind us that when the waters around us are murky and dripping with danger, there is also resilience to be found in staying true to ourselves. We can trust the tools we already have within us to navigate our swampy surroundings, the endurance that flows through our very veins—our ability to show strength and nurturance in equal measure.