diff --git a/src/dogmove.c b/src/dogmove.c
index 0cfa6f23d..1218c305e 100644
--- a/src/dogmove.c
+++ b/src/dogmove.c
@@ -318,7 +318,7 @@ dog_eat(struct monst *mtmp,
             edog->apport += (int) (200L / ((long) edog->dropdist + svm.moves
                                            - edog->droptime));
             if (edog->apport <= 0) {
-                impossible("dog_eat: pet apport <= 0 (%d, %d, %ld, %ld, %d, %ud, %ud)",
+                impossible("dog_eat: pet apport <= 0 (%d, %d, %ld, %ld, %d, %u, %u)",
                             edog->apport, edog->dropdist, edog->droptime,
                             svm.moves,
                             prior_apport,