1.  seahorse(n = noun.animal) sea horse, walrus - either of two large northern marine mammals having ivory tusks and tough hide over thick blubber;
is a kind of pinnatiped, pinniped, pinniped mammal
is a member of genus odobenus, odobenus
has particulars: atlantic walrus, odobenus rosmarus, odobenus divergens, pacific walrus

2.  seahorse(n = noun.animal) sea horse - small fish with horse-like heads bent sharply downward and curled tails; swim in upright position;
is a kind of needlefish, pipefish
is a member of genus hippocampus, hippocampus