The answer is: Whale

Gen 1:21 - The NIV renders this as 'great sea creatures'.

In the grand narrative of creation, the mention of the whale isn’t just a casual note; it signifies a pivotal moment in the emergence of marine life. When Genesis 1:21 speaks of "great sea creatures," it underscores God’s attention to the majestic and awe-inspiring complexity of life itself. The word "great" evokes a sense of wonder, reminding us of the whales' monumental presence in the vast oceans.

There’s a linguistic richness in the term "great sea creatures." In Hebrew, the word is "tanin," which can refer to large and often mythical creatures, hinting at a time when people believed that the sea was filled with marvellous beings. This text potentially reflects the imaginations and fears of ancient peoples who ventured near deep and unexplored waters. On another note, when God's creation is detailed over six days, we see a rhythmic pattern—acute observations being crafted; it emphasizes order and beauty in creation, suggesting the intentionality behind myriad life forms.

Interestingly, tidal folklore often unravels in the life cycles of whales, linking them to concepts of migration, change, and renewal. These silent giants evoke majesty whenever they breach the ocean surface, echoing Genesis's truth that creation reflects divinity—dynamic and ever-evolving. Each time we hear a story about these magnificent mammals, we engage with the echoes of this ancient creation text, sensing the same awe our ancestors felt by the sea's edge.