"Running" is a very difficult trick. Only a small subset of the Animalia, which is itself a small subset of the Eukaryotes, which is only a small subset of life

"Running" is a very difficult trick. Only a small subset of the Animalia, which is itself a small subset of the Eukaryotes, which is only a small subset of life, has managed to do it. "Photosynthesis" is another difficult trick. It's believed that (with the exception of the amoeboid Paulinella chromatophora), all chloroplasts in eukaryotes derive from a single endosymbiotic event that took place over a billion years ago, though after the last common ancestor to animals and plants. What you want requires both tricks to have occurred in the evolutionary history of a single animal. As evolution doesn't go towards a global optimization, but only acts on what's available, the lack of directly solar powered animals does not place a low intrinsic limit on solar technology. An alternate evolutionary history, perhaps where something like Paulinella chromatophora acquired a chloroplast 1 billion years ago instead of 60 million years ago, may have resulted in the world you envision.