The large, highly sensitive ears of the Ferengi, which give them acute hearing, serve as an erogenous zone and act as a cultural measure of business sense and masculinity.
Ferengi ears, always called lobes, are the most prominent feature of the species. They provide hearing far sharper than a human's and are so sensitive that stroking them, a practice known as oo-mox, is a principal form of intimacy. Males have much larger lobes than females, and Ferengi society links their size to commercial talent: to say that someone has the lobes for business is high praise, and to lose them would be disgrace.
Deep Space Nine makes constant use of the idea through Quark, Rom and Nog. In Bar Association Rom suffers a painful ear infection that Doctor Bashir treats, an episode that helps push him towards founding a union, and Ferengi are shown guarding their ears from loud noise and cold.
The Ferengi brain is equally unusual. Its four-lobed structure makes Ferengi minds unreadable to Betazoids, a point first raised in The Next Generation.