Well, I don't care if they do or not, I'm just going to assume they do
I need that for the fanfiction. The person transporting the Ralts egg (the main character's father) gets... um... attacked (so as not to say thorn appart and devoured) by a pack of Mighyena. Ralts mentions latter on that he remembers laughter, but no one appeared to be happy.
LATER in the story the main character and Ralts (now a Gardevoir) come accross that same Mightyena pack and the first thing that warns them of their presence is the cruel, humorless laughter they produce.