diff --git a/lib/galaxy/datatypes/binary.py b/lib/galaxy/datatypes/binary.py
index 63512aa5991..170516f4633 100644
--- a/lib/galaxy/datatypes/binary.py
+++ b/lib/galaxy/datatypes/binary.py
@@ -880,7 +880,7 @@ class RData( Binary ):
     file_ext = 'RData'
 
     def sniff( self, filename ):
-        rdata_header = binascii.hexlify('RDX2\nX\n')
+        rdata_header = binascii.hexlify('\x1f\x8b\x08\x00\x00\x00\x00')
         try:
             header = open(filename).read(7)
             if binascii.b2a_hex(header) == rdata_header: