California Leaf-nosed Bat - Physical Description

Physical Description

The California leaf-nosed bat weighs between 12 and 20 grams, has a wingspan of over 30 centimeters and a body length of over 6 centimeters, and is brown in color. As its name implies, it has a triangular fleshy growth of skin, called a noseleaf, protruding above the nose. This bat is the only bat of the family Phyllostomidae in the United States to have large ears, usually over 2.5 centimeters. It is also one of the most maneuverable in flight. M. californicus seems to spread its uropatagium widely only when hovering or performing other maneuvers requiring a departure from straight level flight, but the extreme maneuverability observed in M. californicus is probably due to the specializations of its sensory equipment. With short, broad wings, it can fly at low speeds using minimal energy. Because of this adaptation, it is not suited for long-distance travel, and is non-migratory.

This bat has an unusual reproductive pattern. After breeding occurs in the fall, the embryos develop very slowly until March, when growth continues at a more normal rate before birth in May or June. Twins are common.

In Macrotus the position of the hind limbs during level flight differs even more form that in most other mammals. The hind limbs are held behind the bat in a spider-leg- like posture, with the femur extending dorsad and caudad, and with the shank partially flexed and extending caudad and more or less downward.

The number of post cervical vertebrae in Macrotus are as follows: twelve thoracic, six lumbar, five sacral, seven caudal.