diff --git a/dlib/dnn/curand_dlibapi.h b/dlib/dnn/curand_dlibapi.h
index 133d6f33a..60a2c67ea 100644
--- a/dlib/dnn/curand_dlibapi.h
+++ b/dlib/dnn/curand_dlibapi.h
@@ -28,8 +28,8 @@ namespace dlib
 
             void fill_gaussian (
                 tensor& data,
-                float mean,
-                float stddev
+                float mean = 0,
+                float stddev = 1
             );
             /*!
                 requires
diff --git a/dlib/dnn/tensor_tools.h b/dlib/dnn/tensor_tools.h
index 865cfe864..b6ab952c4 100644
--- a/dlib/dnn/tensor_tools.h
+++ b/dlib/dnn/tensor_tools.h
@@ -72,8 +72,8 @@ namespace dlib { namespace tt
 
         void fill_gaussian (
             tensor& data,
-            float mean,
-            float stddev
+            float mean = 0,
+            float stddev = 1
         );
         /*!
             requires