April 26, 2011 By
A 255-year-old giant tortoise named Adwaitya died at the Calcutta Zoo. The animal had been brought to India from the Seychelles Islands in the mid-18th century as a present to the English colonial ruler Robert Clive.
Why do giant tortoises live for such a considerable time? So they can reproduce more successfully. Long life spans offer an evolutionary advantage for particular sorts of animals.
It is smart to paste around if you live in an unforeseeable or unpleasant environment where it’s tough to reproduce on regularly. ( Desert animals, for instance, have a tendency to get quite old before they die. ) You’d also wish to have a long life if you could only give birth occasionally for some other reason, or if you spent a load of time caring for every one of your offspring. Each species has its own “life history,” or schedule depending on which it passes on its genes to the new generation. Some animals invest their resources in having plenty of babies while they are young ; others use their resources to live longer.
An animal might live fast if there are a considerable number of predators aroundif you are going to die young, you may as well get the baby-making over with as early as is possible. ( this plan works only in a foreseeable environment, where you know there’ll be adequate food around to feed all of your babies. ) The long-lived animals, alternatively, have frequently developed some way to guard themselves from predators. That’s the reason why armored beastslike turtles, armadillos, and beetlestend to paste around for a bit compared with similarly sized animals. Flying animals also appear to have an advantage ; bats last longer than rodents, maybe because they will be able to escape predators easier. Extraordinarily deadly animals can last a very long time, as wellany powerful protection against predation will do the job. The giant tortoise has an armored shell for protection, but it’s also got 2 other features that correlate with long life.
As an island species, it has enjoyed natural protection from predators over the course of its history. It is also very big, and bigger animals have a tendency to live for longer than tiny ones. ( there are a good deal of exceptions to the bigger-lives-longer ruletake the tiny bat, for instance. Big body size also goes together with living on an island ; click now for an Explainer on island gigantism and dwarfism. ) all these factors interact over the course of an animal’s evolutionary history, so you cannot say one feature causes another. We won’t realize that a tortoise lives to 255 because it has got a shell or because it’s gigantic ; nor are we able to say the tortoise developed a shell or its giant size as it has a long life.
Other sorts of animals especially those with larger brains seem to have developed long life spans for a number of different reasons completely : generally, the more social the animal, the longer it lives. Social insects have more longevity than the lonesome variations : Some flies last only a day or two, while a termite queen can survive for 30 years.