A gorilla is a huge ape that lives in herds. They can easily tear apart your military dwarves. Also, hunters are only risking their lives when hunting them. In other words, try to avoid them or use a ballista at a fortified position, or use ranged weapons from walls if they get too close.
Due to a typo in the raws ("5FINGER" instead of "5FINGERS"), they don't have any fingers on their hands. Since their only means of attacking is their teeth, this does not make them any less dangerous.Verify
[CREATURE:GORILLA] [NAME:gorilla:gorillas:gorilla] [TILE:'G'][COLOR:0:0:1] [LARGE_ROAMING][FREQUENCY:5] [POPULATION_NUMBER:20:50] [CLUSTER_NUMBER:5:10] [PETVALUE:500] [GRASSTRAMPLE:0][NATURAL][PET] [BENIGN][MEANDERER] [PREFSTRING:strength] [BODY:QUADRUPED:2EYES:2EARS:NOSE:2LUNGS:HEART:GUTS:ORGANS:THROAT:NECK:SPINE:BRAIN:MOUTH:5FINGER:5TOES] [SIZE:8] [MAXAGE:30:50] [ATTACK:MAIN:BYTYPE:MOUTH:bite:bites:1:6:GORE][ATTACKFLAG_CANLATCH] [CHILD:10] [FAT:4] [DIURNAL] [BIOME_FOREST_TROPICAL_MOIST_BROADLEAF] [BIOME_SWAMP_TROPICAL_FRESHWATER] [BIOME_SWAMP_TROPICAL_SALTWATER] [BIOME_SWAMP_MANGROVE] [STANDARD_FLESH] [HOMEOTHERM:10067] [LAYERING:100]