diff --git a/src/core.js b/src/core.js
index 323349e8..b882f9b4 100644
--- a/src/core.js
+++ b/src/core.js
@@ -710,15 +710,30 @@ jQuery.extend({
 
 	// arg is for internal usage only
 	map: function( elems, callback, arg ) {
-		var ret = [], value;
+		var value, key, ret = [],
+			i = 0,
+			length = elems.length,
+			// jquery objects are treated as arrays
+			isArray = elems instanceof jQuery || length !== undefined && typeof length === "number" && ( ( length > 0 && elems[ 0 ] && elems[ length -1 ] ) || jQuery.isArray( elems ) ) ;
 
 		// Go through the array, translating each of the items to their
-		// new value (or values).
-		for ( var i = 0, length = elems.length; i < length; i++ ) {
-			value = callback( elems[ i ], i, arg );
+		if ( isArray ) {
+			for ( ; i < length; i++ ) {
+				value = callback( elems[ i ], i, arg );
 
-			if ( value != null ) {
-				ret[ ret.length ] = value;
+				if ( value != null ) {
+					ret[ ret.length ] = value;
+				}
+			}
+
+		// Go thorugh every key on the object,
+		} else {
+			for ( key in elems ) {
+				value = callback( elems[ key ], key, arg );
+
+				if ( value != null ) {
+					ret[ ret.length ] = value;
+				}
 			}
 		}
 
diff --git a/test/unit/core.js b/test/unit/core.js
index 79710025..ed1fb591 100644
--- a/test/unit/core.js
+++ b/test/unit/core.js
@@ -642,7 +642,7 @@ test("first()/last()", function() {
 });
 
 test("map()", function() {
-	expect(2);//expect(6);
+	expect(7);
 
 	same(
 		jQuery("#ap").map(function(){
@@ -660,32 +660,32 @@ test("map()", function() {
 		"Single Map"
 	);
 
-	return;//these haven't been accepted yet
-
 	//for #2616
 	var keys = jQuery.map( {a:1,b:2}, function( v, k ){
 		return k;
-	}, [ ] );
-
+	});
 	equals( keys.join(""), "ab", "Map the keys from a hash to an array" );
 
 	var values = jQuery.map( {a:1,b:2}, function( v, k ){
 		return v;
-	}, [ ] );
-
+	});
 	equals( values.join(""), "12", "Map the values from a hash to an array" );
 
+	// object with length prop
+	var values = jQuery.map( {a:1,b:2, length:3}, function( v, k ){
+		return v;
+	});
+	equals( values.join(""), "123", "Map the values from a hash with a length property to an array" );
+
 	var scripts = document.getElementsByTagName("script");
 	var mapped = jQuery.map( scripts, function( v, k ){
 		return v;
-	}, {length:0} );
-
+	});
 	equals( mapped.length, scripts.length, "Map an array(-like) to a hash" );
 
 	var flat = jQuery.map( Array(4), function( v, k ){
 		return k % 2 ? k : [k,k,k];//try mixing array and regular returns
 	});
-
 	equals( flat.join(""), "00012223", "try the new flatten technique(#2616)" );
 });