>>25926339A Rosebuta can survive for about the same time without sunlight as he can without food, if given normal rations. But it would require an obscene amount of food for a Rosebuta to live off of only food. About three times the normal rations for a Rosebuta (I believe I mentioned the amount of food they usually consume in the prompt answers or biology notes). That’s why Rosestones are so valuable to them. It’s part of the reason why they can normally live.
Tunnelhogs do have established communications with Sunwalkers, noted in a little bit of detail in the .5 chapter of the /risu/-/rose/ story, and have cooperated more and more in recent times. They simply live separately due to a difference in culture that’s formed over ages of separation. It’s just not very normal for them to mingle together since Sunwalkers prefer being above land while Tunnelhogs prefer being below. But there have been plenty of cases where a Tunnelhog has gone above land or a Sunwalker has gone below, usually getting along with the other kind.