can't speak for mountain tortoises, but i think redfoots are a little more shy as babies than they are when they get bigger -- this was the case with mine. though she'd eat from our hands from the first day i got her, she'd bury herself into her substrate a lot, and if you picked her up, it was like she was on a timer -- t-minus any second 'til you got pooped and/or peed on. once she was maybe 5 or 6 inches or so in length, she hid herself less and sought us out more, and is completely mellow about being picked up -- she just dangles out of her shell and looks at you, rather than doing the old put-me-down dance.