That explains our use for K-9s and our apparent build for sucking the marrow out of bones. How does this explain a habit of red meats?
"...red meat..."
I would suspect that red meat eating would be a later development of a more "cultural" type than physical that an already meat digesting, longer living, and intelligent primate would turn to.
The creature that can eat fish that wash up or are grabbed from tidal pools has a wider food selection than the one who can just eat shellfish and are therefor less susceptible to food shortages and competition. The ones capable of properly digesting the fatty fish have even less competition and a wider range of places to live. One of them finds a crippled mouse and gives it a try. Soon its offspring are moving inland to "hunt" by intentionally reach into rodent dens the same way previous generations reached into crab holes. The progression of food sources, habitats, and intelligence levels just continue but the critical meat eating and fat digesting ability of this proto-humanoid is already present from earlier forms.
FTR. Lest some reader think Im trying to pass myself off as some sort of paleoanthropologist, Im not, nor did I sleep in a particular hotel last night, Im just trying to use logical commoners SWAG.