Well the rest of this is my own thinking. What this effectively does is free up calories. What happens with those extra calories depends on the evolutionary pressure. The species could just hunt/eat less and continue on just as they were, or they could switch to more secure or less dangerous foods. For most animals hunting is dangerous, so less hunting would be simply better. For humans, better (more intelligent) use of hunting tools lead to better survival, so the evolutionary pressure is bigger brain to better use tools. For a tiger, more calories could lead to bigger claws or something, or less hunting.

I also think that intelligence depends on the ability to manipulate the environment around you. We have hands and fingers to make things, tools, houses, etc. However intelligent an elephant is, they can never really manipulate the environment around them to great extent. So their evolutionary pressure for bigger brains maxes out. There’s just no need. You see those cartoons about the super intelligent dolphin? Well I don’t think that would ever happen because they can never manipulate the environment round them.