Power law for animal abundances oddly matches '¾ rule' in physiology
On land or sea, when the zebras, gazelles or even plankton fruitfully multiply, their predators’ abundance doesn’t increase quite as much, a new analysis proposes.
This predator-prey relationship— predators increasing at a particular rate that’s less than that of their prey — turned up in studies of the total mass of the top carnivores in Africa’s parks, says study coauthor Ian Hatton of McGill University in Montreal. And the same relationship seems to apply in lakes, oceans and on other continents for top hunters as different as lions and zooplankton, Hatton and colleagues report in the Sept. 4 Science.
The math describing such relationships, known as a power law, incorporates an exponent (power) to relate the change in one factor (predator biomass) to another (prey biomass). In this case, the exponent is about 0.75, indicating that the predator