Allowing animals to leave footprints.

code/modules/mob/living/carbon/human/human.dm

@@ -1662,3 +1662,6 @@
 		else
 			take_damage(rand(10, 20))
 		return organ
+
+/mob/living/carbon/human/leaves_tracks_type()
+	return species.get_move_trail(src)

code/modules/mob/living/living.dm

@@ -1165,3 +1165,6 @@
 			. = new .(src)
 		if(!skip_wounding)
 			take_damage(rand(10,20))
+
+/mob/living/proc/leaves_tracks_type()
+	return

code/modules/mob/living/simple_mob/subtypes/animal/animal.dm

@@ -27,10 +27,14 @@
 	var/scavenger = FALSE // Can eat from corpses.
 	var/burrower = FALSE  // Can dig dens.
 	var/bitesize = 3      // How many reagents to take per nibble
+	var/tracks_type = /obj/effect/decal/cleanable/blood/tracks/paw
 
 /decl/mob_organ_names/quadruped //Most subtypes have this basic body layout.
 	hit_zones = list("head", "torso", "left foreleg", "right foreleg", "left hind leg", "right hind leg", "tail")
 
+/mob/living/simple_mob/animal/leaves_tracks_type()
+	return tracks_type
+
 /mob/living/simple_mob/animal/proc/has_appetite()
 	return TRUE