New Delhi: A new study has revealed that the end of elephant, rhino and polar bear on the Earth has already begun, thanks to the humans for their act of unbalancing the coordination between humanity and nature.
Experts say the Earth is experiencing a sixth mass extinction and human behaviour killed over 320 species and many more are set to follow.
Large animals including elephants, rhinoceroses, polar bears and other species face the highest rate of decline.
According to a new review of scientific literature and analysis of data published in Science, scientists said that previous extinctions were driven by natural planetary transformations or catastrophic asteroid strikes but the current die-off can be associated to human activity.
Rodolfo Dirzo, lead author and a professor of biology at Stanford, designates an era of 'Anthropocene defaunation.'
Since 1500, more than 320 terrestrial vertebrates have become extinct. The current populations of the remaining species show a 25 per cent average decline and the situation is worsening daily.
Across vertebrates, 16 to 33 per cent of all species are estimated to be globally endangered.
Experts further say that larger animals tend to have lower population growth rates than others. Humans hunt for large animals because of their size and meat mass.
FIVE GREAT EXTINCTION EVENTS
End-Ordovician mass extinction
Around 440 million years ago, virtually, all life was in the sea and around 85 per cent of these species vanished.
Late Devonian mass extinction
About 375-359 million years ago, major fish groups were wiped out due to severe environmental changes.
End-Permian mass extinction
This took place 252 million years ago. Around 97 per cent of species that leave a fossil record disappeared forever from the Earth.
End-Triassic mass extinction
Dinosaurs first appeared in the Early Triassic that occurred 201 million years ago.
End-Cretaceous mass extinction
Nearly 66 million years ago, the reign of the dinosaurs came to an end in the End-Cretaceous.
The scientists, while detailing a trouble trend in invertebrate defaunation, said that human population doubled in the past 35 years where as in the same period, the number of invertebrate animals decreased by 45 per cent.
Dirzo said that when human density is high, you get high rates of defaunation, high incidence of rodents and thus high levels of pathogens, which increases the risks of disease transmission.
In case of larger animals, the loss is driven primarily by loss of habitat and global climate disruption, Dirzo added.
