Why must whales have blood that is tolerent to carbon dioxide?

Whales must have blood that is tolerant to carbon dioxide because they spend extended periods underwater, where they hold their breath and engage in deep dives. During these dives, their bodies produce significant amounts of carbon dioxide due to metabolic processes, and their blood needs to effectively manage and buffer these levels to prevent acidosis. Additionally, a higher tolerance allows them to utilize oxygen more efficiently, improving their ability to survive in low-oxygen environments. This adaptation is crucial for their survival in the marine ecosystem.