“The gular pouch is used for prey capture in the pelicans, courtship displays in the frigatebirds, and thermoregulation in most species.² Blood flow to the pouch of the pelican is supplied through midline vessels that send branches laterally and through subramal vessels that send branches medially into the gular sac.¹¹ The inner and outer surfaces of the gular sac are covered with squamous epithelium, with a highly vascular muscular layer between.^11,20” (Fowler and Miller 2003: 118)