Our Central California Bats

Our Central California Bats

Nineteen species of bats occur within California’s Central Region. Several species are rare in the area including the Western Small-footed Myotis, a xeric habitat specialist; the Little Brown Bat, a mesic habitat specialist; and the Western Mastiff Bat, a cliff-dwelling, riparian corridor super-bat.

The most exciting results of the survey so far are the confirmation of regular occurrence of two “free-tailed” bats, the Pocketed and Big Free-tailed Bats and discovery of a “new” species (the former known range of which was northern Los Angeles County), the Western Yellow Bat.

Here’s a list of all of our 20 Central California bats with a few notes about each including their key features:

Y – Indicates species detected during Central California Bat Survey*
N – Indicates our Central Coast bats expected but not yet detected at any of our study sites*
*Data primarily from Fresno, Inyo, Kern, San Luis Obispo, Santa Barbara, Monterey, San Bernardino, and Tulare counties, CA

Vespertilionid Bats

Smaller Vespertilionid Bats

Y – Canyon Bat (Parastrellus hesperus)
Key features: Smallest North American bat (body length: 60-70mm); forearm 25-30mm; dark facial mask; unique (blunt) tragus (unlike Myotis); keeled calcar; one tiny premolar – Myotis have two – however, this is an in-hand only identification trait.

Y – Townsend’s Big-eared Bat (Corynorhinus townsendii pallescens)
Key features: Just slightly larger than large Myotis species (body length 90-115mm); forearm 39-44mm; large ears (30-40mm); distinct horseshoe-shaped lump on nose.

Y – California Myotis (Myotis californicus)
Key features: All-around small bat – body length 65-90mm; forearm 32-38mm; base of hairs typically much darker than tips; foot is very small (5-8mm); forearm is small (< 35mm); calcar is keeled.

Y – Small-footed Myotis (Myotis ciliolabrum; IUCN considers the western race a distinct species, M.  melanorhinus (the “dark-nosed small-footed myotis”). There is little consensus for this designation)
Key features: Rare or absent along coast. Similar to California myotis: Small size (body length 65-85mm); forearm 30-35mm; foot similarly small (5-8 mm), calcar is keeled; dorsal surface of interfemoral membrane furred on anterior half; skull flattened; ears black; typically has distinctive black facial mask.

Y – Long-eared Myotis (Myotis evotis)
Key features: Body length 75-95mm; forearm 36-41mm; extremely long ears for a Myotis (18-25mm); also, ears black, shiny, and hairless.

Y – Little Brown Bat (Myotis lucifugus)
Key features: Rare in SLO, MON, and SBA counties. Small bat; body length 80-95mm; forearm length 36-40mm; wingspan 220-270mm; fur darker on dorsum than ventrum; feet w/long toe hairs that extend to tips of toes.

Y – Fringed (fringe-tailed) Myotis (Myotis thysanodes)
Key features: Body length 75-105mm; relatively long ears (16-20mm); often with notable facial mask; only Myotis w/fringe of (stiff) hairs along edge of interfemoral membrane.

Y – Long-legged Myotis (Myotis volans)
Key features: Body length 95-103mm; forearm 36-42mm; underwing furred near body from knee to elbow; obvious keel on calcar.

Y – Long-eared Myotis (Myotis evotis)
Key features: Body length 75-95mm; forearm 36-41mm; extremely long ears for a Myotis (18-25mm); also, ears black, shiny, and hairless.

Y – Yuma Myotis (Myotis yumanensis)
Key features: Noticeably two-toned (darker on back, lighter on underside); small bat (body length 85-90mm); forearm 32-36mm; large feet (≈10 mm); short ears (13-15mm), lacks keel on the calcar.

Y- Spotted Bat (Euderma maculatum)

Larger Vespertilionid Bats

Y – Pallid Bat (Antrozous pallidus)
Key features: Medium-sized (length 92-135mm); forearm 48-60mm; large eyes; often feeds on the ground; can run on folded wings and hind feet; can hop from ground to catch insects

Y – Big Brown Bat (Eptesicus fuscus)
Key features: Largest locally-occurring bat with uniform brown fur (body length 105-120mm); forearm 45-52mm; tragus blunt (as opposed to pointed in all Myotis species)

Y – Silver-Haired Bat (Lasionycteris noctivagans)
Key features: Medium-sized bat (body length 90-115mm); forearm 39-43mm; interfemoral membrane lightly furred; fur color typically black with silver tips – similar to hoary bat but face NOT distinctly lighter than back

Y – Western Red Bat aka Peter’s Red Bat (Lasiurus frantzii)
Key features: Medium-sized (body length 90-120mm); forearm 38-42mm; males typically brick-red, females are rusty (i.e., browner); body hairs often tipped with white; interfemoral membrane heavily (densely) furred

Y – Western Yellow Bat (Dasypterus xanthinus)

Description being developed for this recently discovered (on the Central Coast) species.

Key features:

Y – Hoary Bat (Aeorestes cinereus)
Key features: Large bat (body length 130-145mm); forearm 50-55mm; face lighter than dorsum (often yellowish); ears distinctively rounded, glossy black in color with naked edges; all-over densely furred.


Molossid (free-tailed) Bats

Y – Mexican (Brazilian) Free-tailed Bat (Tadarida brasiliensis)
Key features: A small bat (body length 90-105mm) with long narrow wings (extremely fast flier); forearm 36-46mm; tail extends out from the interfemoral membrane; long hairs extend from toes; unlike mastiff bat, ears don’t meet in the middle of forehead; notably wrinkled lips.

Y – Western Mastiff Bat (Eumops perotis)
Key features: Rare in SLO, MON, and SBA counties. Largest U.S. bat; body length 140-185mm; forearm 72-82mm; long, narrow wings; approx. half of tail is free from the membrane between hind legs; large ears join at the midline of forehead, noticeable underbite.

Y – Pocketed Free-tailed Bat (Nyctinomops femorosaccus)

Description being developed for this recently discovered (on the Central Coast) species.

Key features: TBA

Y – Big Free-tailed Bat (Nyctinomops macrotis

Description being developed for this recently discovered (on the Central Coast) species.

Key features: TBA

Here’s a link to our Key to California’s Central Coast Bats