diff --git a/code/modules/mob/living/carbon/human/life.dm b/code/modules/mob/living/carbon/human/life.dm
index a5f3fae6a6b..97d9b786a0c 100644
--- a/code/modules/mob/living/carbon/human/life.dm
+++ b/code/modules/mob/living/carbon/human/life.dm
@@ -1322,31 +1322,36 @@
 					if(260 to 280)			bodytemp.icon_state = "temp-3"
 					else					bodytemp.icon_state = "temp-4"
 			else
+				//TODO: precalculate all of this stuff when the species datum is created
+				var/base_temperature = species.body_temperature
+				if(base_temperature == null) //some species don't have a set metabolic temperature
+					base_temperature = (species.heat_level_1 + species.cold_level_1)/2
+				
 				var/temp_step
-				if (bodytemperature >= species.body_temperature)
-					temp_step = (species.heat_level_1 - species.body_temperature)/4
+				if (bodytemperature >= base_temperature)
+					temp_step = (species.heat_level_1 - base_temperature)/4
 
 					if (bodytemperature >= species.heat_level_1)
 						bodytemp.icon_state = "temp4"
-					else if (bodytemperature >= species.body_temperature + temp_step*3)
+					else if (bodytemperature >= base_temperature + temp_step*3)
 						bodytemp.icon_state = "temp3"
-					else if (bodytemperature >= species.body_temperature + temp_step*2)
+					else if (bodytemperature >= base_temperature + temp_step*2)
 						bodytemp.icon_state = "temp2"
-					else if (bodytemperature >= species.body_temperature + temp_step*1)
+					else if (bodytemperature >= base_temperature + temp_step*1)
 						bodytemp.icon_state = "temp1"
 					else
 						bodytemp.icon_state = "temp0"
 
-				else if (bodytemperature < species.body_temperature)
-					temp_step = (species.body_temperature - species.cold_level_1)/4
+				else if (bodytemperature < base_temperature)
+					temp_step = (base_temperature - species.cold_level_1)/4
 
 					if (bodytemperature <= species.cold_level_1)
 						bodytemp.icon_state = "temp-4"
-					else if (bodytemperature <= species.body_temperature - temp_step*3)
+					else if (bodytemperature <= base_temperature - temp_step*3)
 						bodytemp.icon_state = "temp-3"
-					else if (bodytemperature <= species.body_temperature - temp_step*2)
+					else if (bodytemperature <= base_temperature - temp_step*2)
 						bodytemp.icon_state = "temp-2"
-					else if (bodytemperature <= species.body_temperature - temp_step*1)
+					else if (bodytemperature <= base_temperature - temp_step*1)
 						bodytemp.icon_state = "temp-1"
 					else
 						bodytemp.icon_state = "temp0"