What species has the greatest combined mass? All the world’s African elephants, or the oceans’ stock of blue whales (respectively the largest land and sea mammals)? Neither. It is the Antartic krill, weighing in at just two grams and growing to six centimetres long.
What the Antartic krill lacks in individual size it more than makes up in collective heft. It has a combined biomass of between 300 and 700 million tonnes, with many scientists agreeing on c. 500 million tonnes.
This is roughly twice the combined biomass of humans.