diff --git a/doc/fixes35.0 b/doc/fixes35.0
index ae084f321..c18e548ae 100644
--- a/doc/fixes35.0
+++ b/doc/fixes35.0
@@ -899,6 +899,7 @@ pudding corpses behave somewhat differently than before
 mithril armor should have silver color
 lichen corpse is an acid indicator
 camera may contain a picture-painting demon
+some monsters can eat through iron bars
 
 
 Platform- and/or Interface-Specific Fixes
diff --git a/include/extern.h b/include/extern.h
index 227396f54..f5600661d 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1367,6 +1367,7 @@ E boolean FDECL(onscary, (int,int,struct monst *));
 E void FDECL(monflee, (struct monst *, int, BOOLEAN_P, BOOLEAN_P));
 E int FDECL(dochug, (struct monst *));
 E int FDECL(m_move, (struct monst *,int));
+E void FDECL(dissolve_bars, (int,int));
 E boolean FDECL(closed_door, (int,int));
 E boolean FDECL(accessible, (int,int));
 E void FDECL(set_apparxy, (struct monst *));
diff --git a/src/hack.c b/src/hack.c
index ebf1ce891..e8e095da5 100644
--- a/src/hack.c
+++ b/src/hack.c
@@ -347,7 +347,7 @@ still_chewing(x,y)
 
     if (!boulder && IS_ROCK(lev->typ) && !may_dig(x,y)) {
     You("hurt your teeth on the %s.",
-        IS_TREE(lev->typ) ? "tree" : "hard stone");
+        lev->typ == IRONBARS ? "bars" : (IS_TREE(lev->typ) ? "tree" : "hard stone"));
     nomul(0);
     return 1;
     } else if (context.digging.pos.x != x || context.digging.pos.y != y ||
@@ -362,9 +362,10 @@ still_chewing(x,y)
     context.digging.effort =
         (IS_ROCK(lev->typ) && !IS_TREE(lev->typ) ? 30 : 60) + u.udaminc;
     You("start chewing %s %s.",
-        (boulder || IS_TREE(lev->typ)) ? "on a" : "a hole in the",
+        (boulder || IS_TREE(lev->typ) || lev->typ == IRONBARS) ? "on a" : "a hole in the",
         boulder ? "boulder" :
-        IS_TREE(lev->typ) ? "tree" : IS_ROCK(lev->typ) ? "rock" : "door");
+        IS_TREE(lev->typ) ? "tree" : IS_ROCK(lev->typ) ? "rock" :
+	lev->typ == IRONBARS ? "bar" : "door");
     watch_dig((struct monst *)0, x, y, FALSE);
     return 1;
     } else if ((context.digging.effort += (30 + u.udaminc)) <= 100)  {
@@ -373,7 +374,8 @@ still_chewing(x,y)
         context.digging.chew ? "continue" : "begin",
         boulder ? "boulder" :
         IS_TREE(lev->typ) ? "tree" :
-        IS_ROCK(lev->typ) ? "rock" : "door");
+        IS_ROCK(lev->typ) ? "rock" :
+	    lev->typ == IRONBARS ? "bars" : "door");
     context.digging.chew = TRUE;
     watch_dig((struct monst *)0, x, y, FALSE);
     return 1;
@@ -418,6 +420,9 @@ still_chewing(x,y)
     } else if (IS_TREE(lev->typ)) {
     digtxt = "chew through the tree.";
     lev->typ = ROOM;
+    } else if (lev->typ == IRONBARS) {
+	digtxt = "eat through the bars.";
+	dissolve_bars(x,y);
     } else if (lev->typ == SDOOR) {
     if (lev->doormask & D_TRAPPED) {
         lev->doormask = D_NODOOR;
@@ -630,10 +635,15 @@ int mode;
     if (Passes_walls && may_passwall(x,y)) {
         ;	/* do nothing */
     } else if (tmpr->typ == IRONBARS) {
+	    if ((dmgtype(youmonst.data, AD_RUST) ||
+		 dmgtype(youmonst.data, AD_CORR)) &&
+		mode == DO_MOVE && still_chewing(x,y)) {
+		return FALSE;
+	    }
 	    if (!(Passes_walls || passes_bars(youmonst.data))) {
 		if (iflags.mention_walls)
 		    You("cannot pass through the bars.");
-        return FALSE;
+		return FALSE;
 	    }
     } else if (tunnels(youmonst.data) && !needspick(youmonst.data)) {
         /* Eat the rock. */
diff --git a/src/mondata.c b/src/mondata.c
index 98c3244f5..0c26a6005 100644
--- a/src/mondata.c
+++ b/src/mondata.c
@@ -285,6 +285,7 @@ struct permonst *mptr;
 {
     return (boolean) (passes_walls(mptr) || amorphous(mptr) ||
 		      unsolid(mptr) || is_whirly(mptr) || verysmall(mptr) ||
+		      dmgtype(mptr, AD_CORR) || dmgtype(mptr, AD_RUST) ||
 		      (slithy(mptr) && !bigmonst(mptr)));
 }
 
diff --git a/src/monmove.c b/src/monmove.c
index 81eb563d3..a7a3ca46f 100644
--- a/src/monmove.c
+++ b/src/monmove.c
@@ -1180,7 +1180,14 @@ postmov:
 			    add_damage(mtmp->mx, mtmp->my, 0L);
 		    }
 		} else if (levl[mtmp->mx][mtmp->my].typ == IRONBARS) {
-			if (flags.verbose && canseemon(mtmp))
+		    if (may_dig(mtmp->mx,mtmp->my) &&
+			(dmgtype(ptr, AD_RUST) || dmgtype(ptr, AD_CORR))) {
+			if (canseemon(mtmp))
+			    pline("%s eats through the iron bars.",
+				  Monnam(mtmp));
+			dissolve_bars(mtmp->mx, mtmp->my);
+			return(3);
+		    } else if (flags.verbose && canseemon(mtmp))
 			    Norep("%s %s %s the iron bars.", Monnam(mtmp),
 				  /* pluralization fakes verb conjugation */
 				  makeplural(locomotion(ptr, "pass")),
@@ -1266,6 +1273,14 @@ postmov:
 	return(mmoved);
 }
 
+void
+dissolve_bars(x, y)
+register int x, y;
+{
+    levl[x][y].typ = (Is_special(&u.uz) || *in_rooms(x,y,0)) ? ROOM : CORR;
+    newsym(x, y);
+}
+
 boolean
 closed_door(x, y)
 register int x, y;