Kings of Longevity
A look at the amazing variety of animal lifespans
By James Dziezynski
Life is tough at the bottom of the food chain; just ask the mayfly. Put yourself in their wings for a moment--sure, you get a few months in the larval stage enjoying carefree days of molting and dining on diatoms. Then there’s a brief and turbulent time where you enter a state called subimago, a sort of insect adolescence where wings are developed but you aren’t sexually mature. Teenage years are short lived as the subimago phase generally lasts about 3 hours, during which time a majority your friends are eaten by fish or frogs. When the big day comes and adulthood is around the corner you have at the very most 24 hours to reproduce and die, assuming you don’t get eaten first. That’s 24 hours at the very most. The bulk of mayflies are lucky to spend more than 45 minutes in the adult stage, meaning you should plan your mid-life crisis 15 minutes into your adult existence.
The whole process seems rushed but when your method of reproduction prefers quantity over quality, there’s not a whole lot of time to be nostalgic. Most insects, especially those living in climates that seasonally change, are lucky if they can make it to the end of a year. So what’s the best bug to be if you want to have a long life? The cockroach has a reputation as being a hearty, if disgusting, bug due to the fact they can live for quite a while with no head and rumors of being nuclear-bomb-proof but alas, the creepiest crawly only has a lifespan of roughly 10 months. If surviving nuclear holocausts is your game, the fruit fly is actually much more resistant to radiation than cockroaches but you better hope the bombs start dropping during your brief 30 day lifespan.
Luckily, you have roughly 30 million other insects to pick from, many of whom are fortunate enough to see more than one sunset. A species of woolly bear caterpillar living in the high Arctic on Ellesmere Islands has an average lifespan of 14 years (luckily, polar bear don’t care much for bugs). Cicadas have clever survival strategies that allow them to live up to 15 years on average. And if you’re born into royalty in an ant or termite colony, there’s a chance (as queen of the colony) you can live up to 50 years or more.
Of course, insects are just one of the many complicated life-forms that fall under the category of “animals” on Earth. The general rule of thumb for mammals is the smaller you are, the quicker you die with the inverse being true for the big boys (and girls). Reptiles are the champs of long lives, thanks to a slightly different cellular structure than mammals; some species of tortoise don’t reach sexually maturity until they are 90 years old or older! The oldest animal in captivity with a known age is a tortoise that lived to be a ripe old 177 years old. Birds, a sort of mammal-reptile hybrid, have some strong contenders such as the turkey vulture clocking in at 120 years and the African grey parrot at 80 years. The fish family makes a case too, with whale sharks and certain catfish species estimated to live over 100 years or more. And amphibians offer the giant salamander, which is estimated to live up to 70 years.
Let’s put all this into human terms: depending on where in the world we are, our lifespan is between 40-80 years. If we’re lucky and avoid disease and accidents we can get upwards of 100 years, whereupon we look like we’re made out of liver-spotted sheets of dried leather and our memories get a bit fuzzy, which is why you can excuse our centenarians if they brush their teeth with their keys and use their toothbrush to try and unlock the front door. Of our mammal brethren, we are certainly at the high end of the potential life range. Mice average about a year and half; dogs 11 years (15 if they are mixed breeds), housecats 18 years, bison 30 years, hippos 55 years, elephants 70 years. The largest whales are nearly impossible to guess lifespans but Right Whales in the Arctic have been found alive with 150-year old spear tips embedded in their skin. Blue and fin whales are both estimated to live over 120 years if they can avoid their primary predator, man.
Recently a new player in the age game has come to light: the giant squid. Of all the huge and mysterious leviathans patrolling the depths of the ocean, none is as elusive as the giant squid. Besides being notoriously reclusive in the wild they also have the somewhat unfashionable habit of dying when raised in captivity. If ever there was an animal that could keep a secret, it’s the giant squid. This is an animal that is so secretive it has only been captured on grainy film images alive twice: once in still pictures 2004 and once on moving film in 2006. Data from those images plus samples of washed up remains have given some clues to the lifespan of the giant squid. If they follow a growth pattern similar their smaller (and easier to research) cousins, giant squid may live up to 300 years or more. They have very few predators, mainly the sperm whale and possibly pilot whales and pacific sleeper sharks. It stands to reason there may be other old-timers hiding in the darkest depths of the ocean as well, possible prehistoric survivors who rack up the years while staying out of the limelight—and the sunlight.
Aging is perhaps the greatest biological mystery of all time. Scientists speculate mankind is on the threshold of a golden age of age-related research, thanks to advances in stem cell experiments and the ever controversial issue of cloning. Until we know more, the reigning champion of the natural world remains an enigma. The facts seem to point towards the reptile family as kings of the living, though given the vastly unexplored oceans there may be more surprise contenders than just the giant squid. There are even theories that entire ant colonies should be counted as a single consciousness rather than thousands of individual entities. A tiny water born creature known as the hydra seems to avoid the aging process altogether and this absence of senescence hints at biological immortality.
No matter how your days (or hours) are numbered, one thing is true in the animal kingdom: all living things are the direct biological result of those whom came before it. Life is one long chain of heartbeats and nerve impulses, brains and brawn that continue to adapt to our ever-changing world. And while the keys to the mystery of life may not be unlocked in our lifetimes, chances are there’s a baby tortoise in the Galapagos who will be sunning himself on some future equatorial beach when the first genetically modified human hits the 150-year-old mark—or as the tortoises might call him, a greenhorn whippersnapper.
