 Salamanders are not vocal and in most species the sexes look alike , so they use olfactory and tactile cues to identify potential mates , and sexual selection does occur . Pheromones play an important part in the process and may be produced by the abdominal gland in males and by the cloacal glands and skin in both sexes . Males are sometimes to be seen investigating potential mates with their snouts . In Old World newts , Triturus spp . , the males are sexually dimorphic and display in front of the females . Visual cues are also thought to be important in some <unk> species . 
