The aftermath of the Flood marks a dramatic turning point in human history and the relationship between humanity and the natural world. At the dawn of creation, human sustenance was strictly limited to plant life, a tradition of early vegetarianism remembered even in the ancient lore of various nations [אם למקרא]. Now, a fundamental shift occurs. Humanity is granted explicit permission to consume the flesh of all living creatures, encompassing livestock, wild beasts, birds, and even the fish of the sea [רמב״ן, אבן עזרא, הטור הארוך, הכתב והקבלה, ביאור יש״ר, קאסוטו, רד״ק].
The reasons for this profound historical change are multifaceted. A primary approach attributes this new right directly to Noah's personal merit. Because he built the ark, labored tirelessly to care for the animals, and saved them from extinction, he essentially became a partner with the Creator in their survival. Consequently, he earned the right to utilize them as he saw fit [אור החיים, בכור שור, חזקוני, קאסוטו]. Furthermore, before the Flood, humans and animals stood on relatively equal footing as God's creations. However, because the animal kingdom had also corrupted its ways and was ultimately spared only due to Noah's righteousness and subsequent sacrifice, humanity's moral superiority was firmly established, justifying human dominion over the animal world [יריעות שלמה, שפתי חכמים, אור החיים]. From a spiritual perspective, humanity had now ascended to a higher level of existence. Just as a plant achieves a higher purpose when consumed by an animal, an animal is elevated when it provides sustenance for a human being [מלבי״ם].
Beyond moral and spiritual justifications, the shift was driven by immediate practical and physical necessities. Upon emerging from the ark, Noah and his family faced a desolate world devoid of ready crops or fruits. Had they not been allowed to consume meat, they would have starved before new fields could be cultivated [מחוקקי יהודה]. Moreover, the post-Flood world brought severe physical and climatic transformations. Human bodies weakened, lifespans were significantly shortened, and the earth was newly exposed to harsh extremes of cold and heat. Plant life lost its original nutritional vitality, making meat an absolute necessity for maintaining human health and survival [מלבי״ם, רש״ר הירש, ביאור יש״ר].
The newfound allowance to eat meat is conceptually equated to the original permission to consume green herbs. This comparison establishes several crucial principles. First, it clarifies that meat is an addition to the human diet, not a replacement for vegetation [דברי דוד]. More importantly, just as the first humans were permitted to uproot plants from their source of life without restriction, humanity is now authorized to actively take an animal's life for food, rather than being restricted to eating animals that died of natural causes [רש״י, מזרחי, גור אריה, משכיל לדוד, פענח רזא, לבוש האורה]. The parallel to vegetation also contains subtle hints about future legislation. Just as the plant kingdom contains both nourishing herbs and toxic weeds, the comparison implies that a future distinction will be made between pure animals permitted for consumption and impure animals that will be strictly forbidden [רבנו בחיי, חזקוני].
Finally, comparing the permitted animals to wild, uncultivated grass yields important legal insights regarding property and theft. Just as anyone may freely pluck wild grass from an open field without committing theft, a wild animal passing through private property is not considered the possession of the landowner and may be freely hunted [העמק דבר]. This stands in contrast to cultivated garden vegetables, the taking of which constitutes theft [רד״ק, תורה תמימה]. Furthermore, since vegetation was originally designated as food for the animal kingdom as well, the comparison teaches that humans are not only permitted to consume meat themselves but may also feed it to their animals and pets [מחוקקי יהודה].