There is a huge body of evidence showing that size really does matter, both in terms of body mass and cerebral tissue. Researchers in Barcelona studied 493 mammal species and found that a larger brain leads to a longer life.
A smarter animal is better equipped to deal with environmental challenges and less likely to take silly chances, like picking a fight with a much bigger animal. That may seem obvious, but it's less clear why body size should contribute to longer lifespan. Among mammals, the top four are humans, followed by elephants, horses and hippopotamuses, but most likely the hippo wouldn't score all that high on an IQ test.
The turkey buzzard tops the list for birds at 118 years, maybe because it's smart enough to wait for road kill instead of attacking a live animal.
But the giant tortoise is the real champ. The world mourned the passing of Lonesome George in the Galapagos Islands earlier this year. The actual age of old George is unknown, although it's clear he made it well past the century mark. Among the superachievers was Tu'I Malila, who was presented to the royal family of Tonga by Capt. James Cook in 1777. He was thought to be 188 when he died in 1965. That still leaves the question of why size matters. Adrian Bejan, a mechanical engineering professor at Duke University, has spent years studying the relationship between size and lifespan, and he is out with a new idea.
Bejan argues in a paper published this week in Nature Scientific Reports that big animals live longer because they travel farther, thus giving them access to more resources. Mobility is the key. Get off the couch.
If he's right, then that leaves longevity largely in our own hands. Do the right thing and you'll live longer. Physicians tell us that all the time. Don't smoke. Get plenty of exercise. Eat right. Researchers at Newcastle University in England think they have figured out why something like eating a low calorie diet can increase lifespan. Aging is strongly influenced by senescence, the end of a cell's ability to replicate itself. They fed mice a low calorie diet and the accumulation of senescent cells plummeted, thus defeating much of the aging process.
It worked even for older mice, suggesting that eating less – or at least fewer calories – may be our best defense against aging and an early death.
No more ice cream? I'm waiting for a magic pill.