For night rides I often use two headlights on the bike, a taillight, and lightweight to-be-seen lights front and rear on my helmet. Due to a neck injury I can't take too much weight on the helmet so my lights are mostly to help drivers see me.
However the white front helmet light is just bright enough to pick up the glow of most animals' eyes at a reasonable distance, so I'll have a little warning. This does seem to keep deer from darting in front of me. Generally they go the opposite direction. Unfortunately that doesn't work with skunks, squirrels or most small critters.
There are some fairly bright headlights that can be worn on the helmet, while the battery packs can be worn lower on the helmet or elsewhere to minimize the weight. I haven't tried those yet.