The extremely enlarged cochlea (Figure 5) indicates that Tanzanycteris had developed sophisticated echolocation abilities (Habersetzer and Storch 1987, 1992; Novacek 1987; Fenton et al. 1995; Simmons and Geisler 1998). Among extant forms only rhinolophids and Pteronotus parnellii have comparable cochlear enlargement - no other Eocene bat had a cochlea in this size range. Extant bats characterized by similar relative cochlear dimensions uniformly use a highly derived type of sonar navigation known as high-duty-cycle constant-frequency echolocation. This system employs the Doppler shift to avoid self-deafening -- the echolocation call pulse and echo are separated in frequency (Fenton et al. 1995). The majority of extant microbats use low-duty-cycle echolocation in which emitted pulses and returning echoes are separated in time. Bats that use the high-duty-cycle system can forage for fluttering insects in dense forest close to vegetation or the ground (Fenton et al. 1995; Simmons and Geisler 1998), behavior beyond the capability of most low-duty-cycle bats (Fenton et al. 1995). This type of echolocation is consistent with the presence of vegetation that is structurally similar to modern-day miombo woodlands as indicated by Mahenge plant fossils (Herendeen and Jacobs 2000).

The apparent presence of high-duty-cycle echolocation in Tanzanycteris indicates that this specialized form of echolocation originated by the middle Eocene. Echolocation apparently evolved in the common ancestor of all bats and was subsequently lost in megachiropterans (Springer et al. 2001). However, it is likely that rhinolophids and mormoopids acquired high-duty-cycle echolocation independently (Teeling et al. 2002).