diff --git a/lib/kaminari/hooks.rb b/lib/kaminari/hooks.rb
index <HASH>..<HASH> 100644
--- a/lib/kaminari/hooks.rb
+++ b/lib/kaminari/hooks.rb
@@ -18,10 +18,16 @@ module Kaminari
         end
       end
 
+      ## mongo_mapper
       ActiveSupport.on_load(:mongo_mapper) do
-        require 'kaminari/models/mongo_mapper_extension'
-        ::MongoMapper::Document.send :include, Kaminari::MongoMapperExtension::Document
-        ::Plucky::Query.send :include, Kaminari::PluckyCriteriaMethods
+        begin
+          require 'kaminari/mongo_mapper'
+        rescue LoadError
+          ActiveSupport::Deprecation.warn p('Kaminari MongoMapper support has been extracted to a separate gem, and will be removed in the next 1.0 release. Please bundle kaminari-mongo_mapper gem.')
+          require 'kaminari/models/mongo_mapper_extension'
+          ::MongoMapper::Document.send :include, Kaminari::MongoMapperExtension::Document
+          ::Plucky::Query.send :include, Kaminari::PluckyCriteriaMethods
+        end
       end
       require 'kaminari/models/array_extension'
Extract kaminari-mongo_mapper gem, and warn users to use the gemified adapter

The built-in MongoMapper support will be removed from this gem in the <I> release