During the winter, humpbacks fast and live off their fat reserves.
They lay down fat reserves in preparation for the dry season.
His body had eaten all its fat reserves, or so it felt, and was now feeding on the muscles themselves.
Breeding is in the fall and depends on the female having built up sufficient fat reserves.
His body generated its own heat by slowly burning the fat reserves he had stored up during the summer.
Any movement would have burned up the fat reserves whose primary use was keeping him alive.
The monarch requires significant energy to make such a long flight, which is provided by fat reserves.
As the adults cannot take food, they depend on their fat reserves, and usually live for only 12 days.
The young stay in the nest, living off their fat reserves, until the adults return.
During this time the animals live off stored fat reserves.