system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 How come horses and ponies and such have evolved with hooves, but now they need human to tend to them or they'll grow out too much ?

Just saw an ad about abandoned ponies with super long hooves, and asking for money to help them. Sure it's another scam, just got me thinking why wild horses or ponies wouldn't be able to kinda grind off their own hooves, right?
gpt
Wild horses travelled extremely long distances over rough terrain, so their hooves would get worn down naturally.  

Domestic horses are kept in stables so they don't grind them down enough and need human care.

Same thing applies to human fingernails/toenails, animal claws, etc.