diff --git a/dump-bytes.rkt b/dump-bytes.rkt
index 85b8398..750abc6 100644
--- a/dump-bytes.rkt
+++ b/dump-bytes.rkt
@@ -15,7 +15,7 @@
 
 ;; Bytes Exact -> Void
 ;; Prints a pretty hex/ASCII dump of bs on (current-output-port).
-(define (dump-bytes! bs requested-count)
+(define (dump-bytes! bs [requested-count (bytes-length bs)])
   (define count (min requested-count (bytes-length bs)))
   (define clipped (subbytes bs 0 count))
   (define (dump-hex i)