Giant bats live in caves and chasms. They are one size bigger than a minotaur. Giant bats are dangerous opponents and can easily kill unskilled adventurers and dwarves. In fortress mode they generally keep their distance, but they will attack your dwarves if they come too close, and are quite able to kill your average civilian dwarf.
[CREATURE:BAT_GIANT] [NAME:giant bat:giant bats:giant bat] [TILE:'B'][COLOR:0:0:1] [MODVALUE:5] [LARGE_CHASM][DIFFICULTY:2] [FLIER] [GENPOWER:3][NATURAL][PET_EXOTIC][MOUNT_EXOTIC] [PETVALUE:750] [PREFSTRING:terrifying features] [BODY:QUADRUPED:2EYES:2EARS:NOSE:2LUNGS:HEART:GUTS:ORGANS:THROAT:NECK:SPINE:BRAIN:MOUTH] [SIZE:10] [MAXAGE:10:20] [ATTACK:MAIN:BYTYPE:MOUTH:bite:bites:1:6:GORE][ATTACKFLAG_CANLATCH] [CHILD:1][CHILDNAME:giant bat pup:giant bat pups] [RIVERATTACK:1:1:1:1:1:1] [FAT:3] [ALL_ACTIVE] [BIOME_SUBTERRANEAN_CHASM] [STANDARD_FLESH] [HOMEOTHERM:10067] [LAYERING:100]