As I said, replace their corpse with some evaporating item through the ITEMCORPSE token. Problem solved.
Ok... let me give it a shot. I'm a noob, and have not modded in the past. Let me know if this is correct...
[ITEMCORPSE:NOSMELLYROT]
... and I just add that anywhere under the creature I want? See below and let me know if this is correct...
[CREATURE:SQUIRREL_GRAY]
[DESCRIPTION:A small grey rodent found chirping in the trees of temperate woodlands.]
[NAME:gray squirrel:gray squirrels:gray squirrel]
[CASTE_NAME:gray squirrel:gray squirrels:gray squirrel]
[CREATURE_TILE:170][COLOR:7:15:0]
[PETVALUE:10]
[FREQUENCY:100][VERMIN_GROUNDER]
[SMALL_REMAINS][NATURAL][PET_EXOTIC][NO_WINTER]
[NOT_BUTCHERABLE]
[BIOME:ANY_TEMPERATE_FOREST]
[POPULATION_NUMBER:250:500]
[PREFSTRING:tails]
[BODY:QUADRUPED:TAIL:2EYES:2EARS:NOSE:2LUNGS:HEART:GUTS:ORGANS:THROAT:NECK:SPINE:BRAIN:SKULL:4TOES_FQ:5TOES_RQ:MOUTH:RODENT_TEETH:RIBCAGE]
[BODYGLOSS:PAW]
[BODY_DETAIL_PLAN:STANDARD_MATERIALS]
[BODY_DETAIL_PLAN:STANDARD_TISSUES]
[BODY_DETAIL_PLAN:VERTEBRATE_TISSUE_LAYERS:SKIN:FAT:MUSCLE:BONE:CARTILAGE]
[BODY_DETAIL_PLAN:BODY_HAIR_TISSUE_LAYERS:HAIR]
[USE_MATERIAL_TEMPLATE:NAIL:NAIL_TEMPLATE]
[USE_TISSUE_TEMPLATE:NAIL:NAIL_TEMPLATE]
[TISSUE_LAYER:BY_CATEGORY:TOE:NAIL:FRONT]
[SELECT_TISSUE_LAYER:HEART:BY_CATEGORY:HEART]
[PLUS_TISSUE_LAYER:SKIN:BY_CATEGORY:THROAT]
[TL_MAJOR_ARTERIES]
[BODY_DETAIL_PLAN:STANDARD_HEAD_POSITIONS]
[BODY_DETAIL_PLAN:HUMANOID_RIBCAGE_POSITIONS]
[USE_MATERIAL_TEMPLATE:SINEW:SINEW_TEMPLATE]
[TENDONS:LOCAL_CREATURE_MAT:SINEW:200]
[LIGAMENTS:LOCAL_CREATURE_MAT:SINEW:200]
[HAS_NERVES]
[SPEED:900]
[USE_MATERIAL_TEMPLATE:BLOOD:BLOOD_TEMPLATE]
[BLOOD:LOCAL_CREATURE_MAT:BLOOD:LIQUID]
[CREATURE_CLASS:GENERAL_POISON]
[GETS_WOUND_INFECTIONS]
[GETS_INFECTIONS_FROM_ROT]
[USE_MATERIAL_TEMPLATE:PUS:PUS_TEMPLATE]
[PUS:LOCAL_CREATURE_MAT:PUS:LIQUID]
[BODY_SIZE:0:0:300]
[BODY_APPEARANCE_MODIFIER:LENGTH:90:95:98:100:102:105:110]
[BODY_APPEARANCE_MODIFIER:HEIGHT:90:95:98:100:102:105:110]
[BODY_APPEARANCE_MODIFIER:BROADNESS:90:95:98:100:102:105:110]
[MAXAGE:2:3]
[ATTACK:BITE:CHILD_BODYPART_GROUP:BY_CATEGORY:HEAD:BY_CATEGORY:TOOTH]
[ATTACK_SKILL:BITE]
[ATTACK_VERB:bite:bites]
[ATTACK_CONTACT_PERC:100]
[ATTACK_PENETRATION_PERC:100]
[ATTACK_FLAG_EDGE]
[ATTACK_PRIORITY:MAIN]
[ATTACK_FLAG_CANLATCH]
[ATTACK:SCRATCH:CHILD_TISSUE_LAYER_GROUP:BY_TYPE:STANCE:BY_CATEGORY:ALL:NAIL]
[ATTACK_SKILL:GRASP_STRIKE]
[ATTACK_VERB:scratch:scratches]
[ATTACK_CONTACT_PERC:100]
[ATTACK_PENETRATION_PERC:100]
[ATTACK_FLAG_EDGE]
[ATTACK_PRIORITY:SECOND]
[ITEMCORPSE:NOSMELLYROT] [DIURNAL]
[HOMEOTHERM:10067]
[SWIMS_INNATE][SWIM_SPEED:2500]
[MUNDANE]
[CASTE:FEMALE]
[FEMALE]
[CASTE:MALE]
[MALE]
[SELECT_CASTE:ALL]
[SET_TL_GROUP:BY_CATEGORY:ALL:HAIR]
[TL_COLOR_MODIFIER:GRAY:1]
[TLCM_NOUN:hair:SINGULAR]
[SET_TL_GROUP:BY_CATEGORY:ALL:SKIN]
[TL_COLOR_MODIFIER:BROWN:1:BURNT_UMBER:1:CINNAMON:1:COPPER:1:DARK_BROWN:1:DARK_PEACH:1:DARK_TAN:1:ECRU:1:PALE_BROWN:1:PALE_CHESTNUT:1:PALE_PINK:1:PEACH:1:PINK:1:RAW_UMBER:1:SEPIA:1:TAN:1:TAUPE_PALE:1:TAUPE_SANDY:1]
[TLCM_NOUN:skin:SINGULAR]
[SET_TL_GROUP:BY_CATEGORY:EYE:EYE]
[TL_COLOR_MODIFIER:BLACK:1]
[TLCM_NOUN:eyes:PLURAL]