The outcome of adaptation is not necessarily a physical change in an organism. It may instead be innate intelligence, such as adjusting reproduction according to environmental conditions.
Female wild pigs adjust their litters based upon resource availability. When food is scarce, mothers birth about 5 piglets, all the same size. The little ones fight it out for the most productive teats. Not all thrive. Survival becomes a matter of spirit.
When times are less lean, a mother instead produces a litter with piglets of various sizes. This limits sibling rivalry. The bigger piggies get the choice teats, while the little ones get by on teats that give less milk. All have a better shot at survival.