diff --git a/code/modules/mob/living/carbon/human/species/species.dm b/code/modules/mob/living/carbon/human/species/species.dm
index 74e9b637a7b..885d045e191 100644
--- a/code/modules/mob/living/carbon/human/species/species.dm
+++ b/code/modules/mob/living/carbon/human/species/species.dm
@@ -150,6 +150,8 @@
 	var/push_flags = ~HEAVY	// What can we push?
 	var/swap_flags = ~HEAVY	// What can we swap place with?
 
+	var/pass_flags = 0
+
 /datum/species/New()
 	if(hud_type)
 		hud = new hud_type()
@@ -282,6 +284,7 @@
 	H.mob_bump_flag = bump_flag
 	H.mob_swap_flags = swap_flags
 	H.mob_push_flags = push_flags
+	H.pass_flags = pass_flags
 
 /datum/species/proc/handle_death(var/mob/living/carbon/human/H) //Handles any species-specific death events (such as dionaea nymph spawns).
 	return
diff --git a/code/modules/mob/living/carbon/human/species/station/monkey.dm b/code/modules/mob/living/carbon/human/species/station/monkey.dm
index 74293d11768..29082cd27c2 100644
--- a/code/modules/mob/living/carbon/human/species/station/monkey.dm
+++ b/code/modules/mob/living/carbon/human/species/station/monkey.dm
@@ -38,6 +38,8 @@
 	swap_flags = MONKEY|SLIME|SIMPLE_ANIMAL
 	push_flags = MONKEY|SLIME|SIMPLE_ANIMAL|ALIEN
 
+	pass_flags = PASSTABLE
+
 /datum/species/monkey/handle_npc(var/mob/living/carbon/human/H)
 	if(H.stat != CONSCIOUS)
 		return