diff --git a/Resources/Prototypes/Floof/Traits/physical.yml b/Resources/Prototypes/Floof/Traits/physical.yml
index d8e88556dd..f69a3c1c6c 100644
--- a/Resources/Prototypes/Floof/Traits/physical.yml
+++ b/Resources/Prototypes/Floof/Traits/physical.yml
@@ -95,6 +95,10 @@
     species:
     - Felinid # They don't need to be lighter
     - Rodentia
+  - !type:CharacterTraitRequirement
+    inverted: true
+    traits:
+    - Heavyweight
   functions:
     - !type:TraitAddComponent
       components:
diff --git a/Resources/Prototypes/_DEN/Traits/physical.yml b/Resources/Prototypes/_DEN/Traits/physical.yml
index 9732f0f625..06daf19e81 100644
--- a/Resources/Prototypes/_DEN/Traits/physical.yml
+++ b/Resources/Prototypes/_DEN/Traits/physical.yml
@@ -12,6 +12,10 @@
     inverted: true
     species:
     - Oni
+  - !type:CharacterTraitRequirement
+    inverted: true
+    traits:
+    - Lightweight
   functions:
     - !type:TraitAddComponent
       components: