Wild mammals only weigh 10 percent of human weight in total.

About the episode

You can map out how things are going with living beings on earth in various ways. Researchers from Israel chose to calculate how many of different groups are walking around by looking at their total weight.

All of humanity, they calculated, accounts for 390 million tons. When they next looked at the proportion of wild mammals living on land, they were shocked. All wild mammals together weigh 22 million tons. Less than 10 percent of the total weight of humanity.

They also looked at the animals we keep as pets and livestock. These turn out to be good for another 630 million tons. Pigs alone weigh almost twice as much as all wild mammals combined. The mammals in the sea are also doing badly. Together they weigh only 40 million tons, according to the calculations.

According to the researchers, it is a painful wake-up call. The umpteenth perhaps, but one that perhaps shows better than ever how little of the wild nature on our planet is left.

Of course, these animals have not all stood on a scale and they have had to use estimates here and there in the research, but even according to scientists who were not involved, it is a good start.

Follow-up research will examine whether they can use comparable calculations to say something about the decline in wild mammals over the past 100 years.

Read more about the research here: ‘A wake-up call’: total weight of wild mammals less than 10% of humanity’s or here: Who rules Earth? Wild mammals far outweighed by humans and domestic animals.