The struggle for existence occurs not in fights, but in the competition for limited feeding areas and for the occupancy of areas free from meat-eating animals.
The researchers conclude that smaller carnivores would have had an advantage in environments with predominantly fast prey, and bigger ones where prey was slower and larger.
As a consequence, the animals of the Antarctic continental shelf have been free for millions of years from the attentions of predators, such as crabs and sharks, that cannot cope with the cold.
The carnivore, nicknamed Banjo, which was found near two giant herbivores in a waterhole in Winton, is the most complete meat-eater ever found in the country.
The poor soil of bogs, for example, offers little nitrogen and phosphorus, so carnivorous plants enjoy an advantage over plants that obtain these nutrients by more conventional means.
Carnivorous plants are so finely tuned to low levels of nitrogen that this extra fertilizer is overloading their systems, and they eventually burn themselves out and die.