Talking Defensively, a Dual Use for the Brachial Gland Exudate of Slow and Pygmy Lorises

Abstract

On the ventral side of the elbow of the both the slow (Nycticebus bengalensis, N. coucang) and pygmy (N. pygmaeus) lorises, one can perceive a slightly raised, fairly hair-free but barely visible swelling, termed the brachial gland (Figure 12.1). Observers of captive lorises have found that when the animal is disturbed during capture and handling, the gland secretes about 10 microliters (µl) of a clear, strong-smelling liquid in the form of an apocrine sweat. Typically, male and female lorises assumed a defensive position with head bent downward between uplifted forelegs, like a miniature prize fighter in a clinch, while imparting gland exudate to the head and neck (Fitch-Snyder, 1996). The lorises frequently licked their own brachial gland regions, and also wiped these glands against their heads. The gland is active in lorises as young as 6 weeks (Fitch-Snyder, unpubl. data).