MorphologyRead full entry
Natalus stamineus is a very small, delicate, long-winged bat, ranging in weight from 3 to 5 g. Head and body length of Mexican funnel-eared bats is 38 to 46 mm; the tail length is from 47 to 52 mm; the length of hind foot is 8 to 9 mm; the length of the ear is 14 to 16 mm; the length of forearm is 36 to 39 mm. The sexes are similar in size.
The upper parts of this species are pale orange-brown or yellowish, with their under parts being yellow. The funnel-shaped ears are broad and cream colored, with black edges. The ears are angled forward. The species possesses very small eyes. Their faces are triangular, with pale pink skin and a mustache over the sides of their mouth.
Adult male Mexican funnel-eared bats have a gland-like structure in the center of their foreheads known as the natalid organ. This gland is thought to be found only in the Natalidae, but there is not much known about its function.
The tail is long and completely enclosed in the interfemoral membrane. The tail is longer than the head and body length. This characteristic is unique to N. stramineus. The membrane is pale brown in color, with the edge fringed with short hair. The legs, tail, and arm bones are pink, contrasting with the brown membrane. The thumb is short and is almost enveloped in the antebrachial membrane, and the third phalanx of the third finger remains cartilaginous even in the adult. The wings are long and narrow.
The dental formula is 2/3 1/1 3/3 3/3=38.
Range mass: 3 to 5 g.
Range length: 38 to 46 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike