Early researchers suggested that humans transition from walking to running in order to minimize energetic costs.

It is common to express the energetic cost of running as the energy cost to travel a given distance.

Meaning that there are speeds at which the energetic cost to run a given distance is minimized.

Interestingly, there is no detectable difference in energetic cost between stances.

"For a mammal, the major energetic cost to the female is gestation and lactation, not the eggs themselves," he said.

Each response pathway is modeled to have a high energetic cost.

Such costs include increased visibility to predators and energetic costs to maintain them.

While successful predation results in a gain of energy, hunting invariably involves energetic costs as well.

The energetic costs of each activity the sunbirds exhibit during the day has been calculated.