it's a dangerous world to live in. just the other day i built a well over an underground lake in a cavern layer. every now and then a giant bat would fly up the well and into the room, flap around a bit, and then leave back down the well. but then one time one of the children was in the room and in a panic running away from the giant bat ended up falling down the well and drowning.
To my knowledge mounts are currently only available to the player in Adventure Mode. I could be wrong though. As far as I understand it mounts aren't working in Fortress mode for the player but do work for enemies who enter the map riding them.
They should be trainable though. Also those things are massive, like several times the size of an adult dwarf so the child falling down the well in fear shouldn't be too surprising. Max giant bat size is 200k cm^3 while max dwarf size is 60k cm^3. Max size figures are pretty good for getting a general idea of the size of these things lol.
well the cavern is full of hostile ant people and they've been killing everything that comes near including a series of forgotten beasts, i need the help