The Collaborative International Dictionary of English v.0.48:

Jararaca \Jar`a*ra"ca\, n. [Pg., from the native name.] (Zool.)
   A poisonous serpent of Brazil (Bothrops jararaca), about
   eighteen inches long, and of a dusky, brownish color,
   variegated with red and black spots.
   [1913 Webster]