The Collaborative International Dictionary of English v.0.48:

Hooded \Hood"ed\, a.
   1. Covered with a hood.
      [1913 Webster]

   2. Furnished with a hood or something like a hood.
      [1913 Webster]

   3. Hood-shaped; esp. (Bot.), rolled up like a cornet of
      paper; cuculate, as the spethe of the Indian turnip.
      [1913 Webster]

   4. (Zool.)
      (a) Having the head conspicuously different in color from
          the rest of the plumage; -- said of birds.
      (b) Having a hoodlike crest or prominence on the head or
          neck; as, the hooded seal; a hooded snake.
          [1913 Webster]

   Hooded crow, a European crow (Corvus cornix); -- called
      also hoody, dun crow, and royston crow.

   Hooded gull, the European black-headed pewit or gull.

   Hooded merganser. See Merganser.

   Hooded seal, a large North Atlantic seal (Cystophora
      cristata). The male has a large, inflatible, hoodlike sac
      upon the head. Called also hoodcap.

   Hooded sheldrake, the hooded merganser. See Merganser.

   Hooded snake. See Cobra de capello, Asp, Haje, etc.


   Hooded warbler, a small American warbler (Sylvania
      mitrata).
      [1913 Webster]

WordNet (r) 3.0 (2006):

hooded seal
    n 1: medium-sized blackish-grey seal with large inflatable sac
         on the head; of Arctic and northern Atlantic waters [syn:
         hooded seal, bladdernose, Cystophora cristata]