[Improvement on Spiky Body]

Maybe when a baby nichling is born with the spikey body the spikes could be "soft" and ineffective kind of like how baby hedgehogs and porcupines are born. Maybe after they age a couple of days the spikes will harden and become useful.

[Feature Suggestion: Nocturnal animals]

I love the idea of having a nighttime/nocturnal mode. A good replacement for the day time predators like the blue birds could be some sort of owl like creature which could perch in/on trees and otherwise works the same way stealing baby niches if they have one gem and are left unattended. For the bearyena replacement I'm not sure... I would suggest a fox like creature kind of like the arctic ram foxes but a bit different. It could attack adult nichlings kind of like a bearyena, but if it were to attack a baby nichling it would try to run away with it and you would have to chase it and kill it to try to save the baby. If it got away into a fox den or something then it would then "eat" the baby nichling. I know this would be extremely difficult if not impossible and would probably take a very, very long time being that you would basically be remaking the entire game to work at night time and replacing all the predators, but if it were to happen these would be my suggestions for possible predators that could work in a nocturnal environment.

[Ram Fox Bug]

I've noticed that in sandbox mode in the snowy biomes that the arctic ram foxes will sometimes if not always have infinite lives. The lifespan bar will fill up but they will never "die" unless you physically attack them. If you click on them and the lifespan bar is full and you pass the day they will just live forever. I haven't actually tested this in story mode yet, but my guess is that its bugged too. Its not to big of a bug, but it might be something to look into.