pronk
    v 1: jump straight up; "kangaroos pronk"

pronk \pronk\ v. i.
   To jump straight up or almost straight up; -- used of
   kangaroos and gazelles.
   [WordNet 1.5]

   Note: Some less common gaits used only by few animals are the
         ricochet, the pronk and the bound. The ricochet is the
         gait principally employed by a class of animals such as
         the kangaroo. The pronk is a gait used by quadrupeds
         such as gazelle and it is equivalent to the ricochet
         except that both the front and back sets of of feet
         perform the same action. The bound is used by a few
         small quadrupeds such as squirrels and dogs. In the
         bound support alternates between pairs of legs, with
         the fore and hind acting to push the body forward.
                                                  --Ionnas
                                                  Poulakakis

                                                  (http://www.cim.mcgill.ca/~poulakas/legged_locomotion/gaits.html)
         [PJC]