diff --git a/requests/api.py b/requests/api.py
index 9cea79af..f192b8f5 100644
--- a/requests/api.py
+++ b/requests/api.py
@@ -38,10 +38,19 @@ def request(method, url, **kwargs):
     :param cert: (optional) if String, path to ssl client cert file (.pem). If Tuple, ('cert', 'key') pair.
     """
 
-    s = kwargs.pop('session') if 'session' in kwargs else sessions.session()
-    return s.request(method=method, url=url, **kwargs)
-
+    # if this session was passed in, leave it open (and retain pooled connections);
+    # if we're making it just for this call, then close it when we're done.
+    adhoc_session = False
+    session = kwargs.pop('session', None)
+    if session is None:
+        session = sessions.session()
+        adhoc_session = True
 
+    try:
+        return session.request(method=method, url=url, **kwargs)
+    finally:
+        if adhoc_session:
+            session.close()
 
 def get(url, **kwargs):
     """Sends a GET request. Returns :class:`Response` object.
diff --git a/requests/models.py b/requests/models.py
index 2c0c7bdd..e42ab366 100644
--- a/requests/models.py
+++ b/requests/models.py
@@ -57,7 +57,7 @@ class Request(object):
         proxies=None,
         hooks=None,
         config=None,
-        prefetch=False,
+        prefetch=True,
         _poolmanager=None,
         verify=None,
         session=None,
@@ -458,7 +458,7 @@ class Request(object):
         except ValueError:
             return False
 
-    def send(self, anyway=False, prefetch=False):
+    def send(self, anyway=False, prefetch=True):
         """Sends the request. Returns True if successful, False if not.
         If there was an HTTPError during transmission,
         self.response.status_code will contain the HTTPError code.
@@ -774,6 +774,8 @@ class Response(object):
                 self._content = None
 
         self._content_consumed = True
+        # don't need to release the connection; that's been handled by urllib3
+        # since we exhausted the data.
         return self._content
 
     @property
diff --git a/requests/sessions.py b/requests/sessions.py
index 3113c787..73c7b17b 100644
--- a/requests/sessions.py
+++ b/requests/sessions.py
@@ -66,7 +66,7 @@ class Session(object):
         hooks=None,
         params=None,
         config=None,
-        prefetch=False,
+        prefetch=True,
         verify=True,
         cert=None):
 
@@ -105,7 +105,15 @@ class Session(object):
         return self
 
     def __exit__(self, *args):
-        pass
+        self.close()
+
+    def close(self):
+        """Dispose of any internal state.
+
+        Currently, this just closes the PoolManager, which closes pooled
+        connections.
+        """
+        self.poolmanager.clear()
 
     def request(self, method, url,
         params=None,
@@ -120,7 +128,7 @@ class Session(object):
         hooks=None,
         return_response=True,
         config=None,
-        prefetch=False,
+        prefetch=None,
         verify=None,
         cert=None):
 
@@ -140,7 +148,7 @@ class Session(object):
         :param proxies: (optional) Dictionary mapping protocol to the URL of the proxy.
         :param return_response: (optional) If False, an un-sent Request object will returned.
         :param config: (optional) A configuration dictionary. See ``request.defaults`` for allowed keys and their default values.
-        :param prefetch: (optional) if ``True``, the response content will be immediately downloaded.
+        :param prefetch: (optional) whether to immediately download the response content. Defaults to ``True``.
         :param verify: (optional) if ``True``, the SSL cert will be verified. A CA_BUNDLE path can also be provided.
         :param cert: (optional) if String, path to ssl client cert file (.pem). If Tuple, ('cert', 'key') pair.
         """
@@ -153,7 +161,7 @@ class Session(object):
         headers = {} if headers is None else headers
         params = {} if params is None else params
         hooks = {} if hooks is None else hooks
-        prefetch = self.prefetch or prefetch
+        prefetch = prefetch if prefetch is not None else self.prefetch
 
         # use session's hooks as defaults
         for key, cb in list(self.hooks.items()):
diff --git a/tests/informal/test_leaked_connections.py b/tests/informal/test_leaked_connections.py
new file mode 100644
index 00000000..5357bf2f
--- /dev/null
+++ b/tests/informal/test_leaked_connections.py
@@ -0,0 +1,26 @@
+"""
+This is an informal test originally written by Bluehorn;
+it verifies that Requests does not leak connections when
+the body of the request is not read.
+"""
+
+import gc, os, subprocess, requests, sys
+
+def main():
+    gc.disable()
+
+    for x in range(20):
+        requests.head("http://www.google.com/")
+
+    print("Open sockets after 20 head requests:")
+    pid = os.getpid()
+    subprocess.call("lsof -p%d -a -iTCP" % (pid,), shell=True)
+
+    gcresult = gc.collect()
+    print("Garbage collection result: %s" % (gcresult,))
+
+    print("Open sockets after garbage collection:")
+    subprocess.call("lsof -p%d -a -iTCP" % (pid,), shell=True)
+
+if __name__ == '__main__':
+    sys.exit(main())
diff --git a/tests/test_requests.py b/tests/test_requests.py
index 9ddc58b4..6b7b57a3 100755
--- a/tests/test_requests.py
+++ b/tests/test_requests.py
@@ -807,9 +807,9 @@ class RequestsTestSuite(TestSetup, TestBaseMixin, unittest.TestCase):
         assert 'k' in c
 
         ds1 = pickle.loads(pickle.dumps(requests.session()))
-        ds2 = pickle.loads(pickle.dumps(requests.session(prefetch=True)))
-        assert not ds1.prefetch
-        assert ds2.prefetch
+        ds2 = pickle.loads(pickle.dumps(requests.session(prefetch=False)))
+        assert ds1.prefetch
+        assert not ds2.prefetch
 
     # def test_invalid_content(self):
     #     # WARNING: if you're using a terrible DNS provider (comcast),
@@ -858,7 +858,7 @@ class RequestsTestSuite(TestSetup, TestBaseMixin, unittest.TestCase):
         )
 
         # Make a request and monkey-patch its contents
-        r = get(httpbin('get'))
+        r = get(httpbin('get'), prefetch=False)
         r.raw = StringIO(quote)
 
         lines = list(r.iter_lines())