DARWIN was right! Animals living on islands may be tamer compared to their relatives on the mainland, according to the new study. The study confirms an idea presented by Charles Darwin while drafting theories of evolution. You may have studied about Darwin and evolution in your higher secondary classes, so you may be interested in knowing this.
A corollary of Darwin's revolutionary idea was that organisms would also evolve to lose structures, functions, and behaviors they mo longer needed when environmental circumstances changed, researchers said.
Darwin noted that island animals often acted tame, and presumed that they had evolved to be so after coming to inhabit islands that lacked most predators.
But more than 150 years later that almost casual observations remained to come under scientific scrutiny.
A team of researchers have now showed that island lizards are indeed "tame" as compared with their mainland relatives. The researchers were able to approach island lizard more closely than they could approach mainland lizards.
"Our study confirms Darwin's observations and numerous anecdotal reports of island tameness, " said Theodore Garland, a professor of biology at University of California, Riverside and one of the paper's co-authors.
The researcher conducted analyses of relationships of flight initiation distance (the predator-prey distance when the prey starts to flee) to distance to mainland, island area, and occupation of an island for 66 lizards species, taking into account differences in prey size and predator approach speed.
They analysed island and mainland lizard species from five continents and islands in the Atlantic and pacific Oceans and the Caribbean and the Mediterranean Seas. Their results showed that island tameness exists and that flight initiation distance decreases as distance from mainland increases.
In other words, island lizards were more accessible the farther the islands were from the mainland, researchers said.
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