When the tiny worm Caenorhabditis elegans cannot sense what is going on in its immediate surroundings, there is a surprising payoff.
It lives up to twice as long as normal, according to Javier Apted and Cynthia Kenyon of the University of California at San Francisco.
They have found that 'nematode' worms that have defective sensory organs can double their lifespan, without any apparent change in behaviour.
This suggests that, in nematodes at least, longevity is not simply programmed into the genes but can be altered by feedback through the nervous system.
The role of nervous system in aging could not be remarked upon*.
The naked mole rat (Heterocephalus glaber) may help scientists to understand longevity.
Although it is just the size of a gerbil, it lives over six times as long: it can survive 26 years or more.
A creature's maximum lifespan is dictated by how well its cells and organs cope with prolonged use.
Mole rats live in large, social colonies in underground burrows.
Occasionally attacked by snakes, they cooperate to defend their homes, allowing many to live long, comfortable lives.
Other animals with protection from predators, such as spines, shells or the ability to fly, also tend to outlive others of the same size.
The queen of a mole-rat colony can produce as many as 100 pups per year well into her twenties.
Evolution should favour longevity if a species continues to reproduce into old age ‐ living one more year would be advantageous if it meant that new offspring would be likely.
A low metabolic rate, for example, might reduce oxygen damage to cells.
It could be one of the common explanations of their longevity.
The mechanism of slow metabolic rate in these rodents is still unknown**.
Diet during the days immediately following conception can be crucial for health in later life, new research suggests.
A low protein diet in the few days before the embryo implants in the uterus wall can cause high blood pressure in rats.
It could have some influence on the age related disease onset too***.