Western Small-footed Myotis (Myotis ciliolabrum) lives in desert rocky areas across Western North America. Its conservation status is Least Concern.
Fascinating facts about the Western Small-footed Myotis
- The western small-footed bat's feet are remarkably tiny, measuring only about half the length of its tibia. This proportion is striking given the bat's overall body size of just 8 to 10 cm in total length. Such diminutive feet are a distinctive feature that helps differentiate it from larger-footed relatives. Their small size is reflected in the species' common name, which directly references this trait.
- Male western small-footed bats usually spend daylight hours alone, seeking solitary roosts in caves, crevices, artificial structures or under loose bark. In contrast, nursing females gather in small colonies that can contain up to nineteen individuals, providing warmth and protection for their young. These daytime roosting habits reflect a clear sexual difference in social behaviour, with females forming temporary groups only during the breeding season.
- The echolocation calls of the western small-footed bat are brief, lasting only 1 to 3 milliseconds, and they differ across the species' range. In Washington state, recordings show each call sweeps from a high of 60 kHz down to 40 kHz. This rapid frequency modulation enables the bat to detect and capture insects while flying slowly and maneuverably near water or rocky bluffs.
- Western small-footed bats are tiny, weighing just 4 to 5 g, with females a little larger than males. Their compact body measures only 8 to 10 cm in total length and they sport a modest 24 cm wingspan, giving them a low wing loading of 6.7 N/m².
- A distinctive black facial mask covers the muzzle and chin of the western small-footed bat, a feature absent in the otherwise similar California myotis. This mask, together with the species' 11 to 16 mm long black ears, provides a reliable field mark for identification across their overlapping range. The mask contrasts with their yellowish-brown fur and paler underparts, highlighting the bat's unique colour pattern.
Sources
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At a glance
RangeWestern North America
HabitatDesert rocky areas
DietInsects and spiders
About the Western Small-footed Myotis
In the velvety darkness of a desert evening, the Western Small-footed Myotis unfurls its delicate wings, a whispered promise of aerial acrobatics to come. As it dances through the air, its high-pitched calls weaving an intricate tapestry of sound, this tiny bat navigates the arid landscape with an uncanny precision, homing in on the faint rustle of insect wings with an unerring instinct. With each fluttering heartbeat, it embodies the essence of nocturnal magic, a fleeting, ethereal presence that vanishes as suddenly as it appears.
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