I think children (human) who aren't taught to walk do learn for themselves - I know from what my sister said that my niece learned to climb at an age when mum and dad didn't even know she could stand up! Went missing one day - my sister had gone into the kitchen and when she came back, no kid! finally discovered her on a shelf among the records!
I agree, my brother's firstborn never escaped the crib and though he had tons of people trying to teach him to walk, he didn't bother till he was darn good and ready,
his brother (who nobody had spent that time on) was climbing out of his crib and walking around coffee tables at 9-10 months old. They'll figure it out when they're ready (as soon as something interesting enough motivates them to)