Chances are, a mouse in the wild will live less than a year before stumbling upon a hungry falcon or feline.
Even if that mouse manages to avoid its natural predators for a couple of years, it will likely develop cancerous tumors before long, bringing an end to its characteristically short life cycle.
Humans stand a much better chance of a living a long life before encountering an unlucky circumstance or illness. But some species seem to defy the odds altogether.
Mark Haussmann, an assistant professor of biology at Bucknell University, was interested in aging and why some animals live longer, healthier lives while others survive only a few years. Haussmann studied cacti and turtles before zeroing in on a small, marine bird that contradicts traditional assumptions about aging.
"Leach's storm-petrels should die young but live a long life and break the conventional rules," he said. "First of all, they're small, and there tends to be a relationship between body size and life span. Elephants live longer than humans. Humans live longer than mice. So this bird shouldn't live long, but it does."
Haussmann, 33, stumbled upon some groundbreaking information in his work. His studies of storm-petrels have shown that certain characteristics of DNA - specifically lengths of the protective telomeres at the tips of DNA - are associated with species that live longer lives and possibly with how susceptible they are to cancer-causing tumors.
His work could be used as a springboard for drug companies studying cell division and cancer-treating drugs.
Protective 'caps' on DNA figure into age
Haussmann, who joined Bucknell this year, is continuing research he began at Kenyon College in Ohio with the help of a $535,000 National Science Foundation grant. He studied the birds on Kent Island in the Bay of Fundy in Canada, where a colony of storm-petrels comes to nest each spring.
Leach's storm-petrels, which are about the size of a robin, spend the majority of their lives on the open sea and come to land only to breed. They have a fast metabolism, high body temperature and high glucose level, all of which should shorten their lifespan, but storm-petrels can live to be up to 40 years old.
A colony of the birds has been studied on Kent Island since the mid-1930s, and comprehensive records have been kept since the 1950s.
Previously, Haussmann measured telomere length in five species of birds with life spans ranging from five to 40 years. The studies found that those with shorter life spans, such as zebra finches, lost their protective telomere caps quickly over time. Species such as the common tern, which lives to be about 30 years old, had less shortening over time.
Storm- petrels were in a class of their own.
"Storm-petrels were the only species where the telomeres actually seemed to be getting longer over time," Haussmann said.
An enzyme in cells called telomerase has the job of building telomeres. When telomeres get too short, cells can no longer divide, and this contributes to the aging process. But, unregulated telomerase can result in runaway cell division.
"Turning on telomerase comes with a cost, and the cost is tumor formation," Haussmann said. "So, telomerase activity has to be closely regulated."
Even though telomerase levels are high in storm-petrels, the incidence of cancer in storm-petrels and other marine birds appears to be quite low.