JERUSALEM, Oct. 27 (Xinhua) -- An international research team has discovered that the total movement of humans is about 40 times greater than that of all wild land mammals, birds, and insects together, the Weizmann Institute of Science (WIS) said in a statement on Monday.
The study, published in Nature Ecology & Evolution, showed that human movement has increased by 4,000 percent since the Industrial Revolution, some 170 years ago. In the same period, the movement of marine animals has dropped by about 60 percent.
As movement is essential for life, and animals traveling to find food, escape danger, and connect different ecosystems, the scientists warned that the global drop in animal movement is a clear sign that nature is under pressure.
To compare humans and animals, the researchers created a new measure that combines the total weight of a species with the distance it travels in a year.
Using this, they found that the total movement of humans on foot is six times greater than the combined movement of all wild land mammals, birds, and arthropods.
According to the study, most human movement happens by car or motorbike, followed by air travel, walking, and cycling, with each person traveling an average of 30 km a day.
The researchers noted that a single airline's energy use equals the total energy all wild birds on Earth expend in flight over a year.
An accompanying study headed by WIS and published in Nature Communications has found that since 1850, the combined weight of wild land and marine mammals has dropped by about 70 percent, falling from around 200 million tonnes to just 60 million tonnes.
During the same period, the weight of humans increased by about 700 percent, and that of farm animals by 400 percent.
Together, people and their livestock now make up about 1.1 billion tonnes, showing how much humanity has grown while wildlife has declined.
This study revealed the extent of humanity's dominance over wildlife and how difficult it is to undo the damage humans inflict on nature, according to the researchers.
In particular, marine mammal biomass has collapsed to about 30 percent of 1850 levels due to industrial hunting. ■
