NOTES ON THE LEAST BROWN BAT: MYOTIS SUBULATUS LEIBII
Au ho (s): Cha les E. Moh
Sou ce:
P oceedings o he Pennsyl ania Academy o Science
, 1936, Vol. 10 (1936), pp.
62-65
Published by: Penn S a e Uni e si y P ess
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62 PENNSYLVANIA ACADEMY OF SCIENCE
NOTES ON THE LEAST BROWN BAT MYOTIS
SUBULATUS LEIBII
By Cha les E. Moh
Reading Public Museum
In Janua y, 1931, I checked h ough Mille and Allen's bulle in on
"The Ame ican Ba s o he Genus Myo is and Pizonyx" in an e o o
lea n jus wha ba s migh be expec ed o occu in Pennsyl ania. I was
su p ised o ind ha a newly-desc ibed species, Myo is sodalis, had been
" aken in Feb ua y om a ca e in Cen e Coun y, Pa." Communica-
ion wi h Ve non Bailey, he collec o , led me o belie e he locali y was
Woodwa d Ca e.
Acco dingly, on Janua y 28, 1931, I isi ed ha ca e, collec ed a
dozen o so ba s and b ough hem back o he zoology labo a o y a
Bucknell Uni e si y. Has y examina ion indica ed ha he e we e no
Myo is sodalis among hem. In he p ess o wo k he ba s we e neglec ed,
se e al died, and la e he mummi ied skins we e ca ied along o he
Heading Museum. The e Ea l L. Poole, assis an di ec o , in looking
o e hem ecognized one o hem as Myo is subula us leibii, he Leas
B own Ba , which, wi h he excep ion o a wes e n Pipis ellus, is he
smalles ba in No h Ame ica.
This was he i s eco d o Pennsyl ania, añd a he ime o he
epo on i s disco e y,1 he nin h specimen eco ded in he li e a u e.2
In 1933, I made a ca e ul check on museum and p i a e collec ions, and
al hough his species has been known since 1842, I lea ned o he exis-
ence o only 18 specimens.3 Since hen Ve non Bailey has epo ed ind-
ing i in Colossal Ca e, in he Mammo h Ca e a ea,4 bu has only a single
specimen.
This appa en sca ci y o e he a he ex ensi e ange shown in
Map 1 is in ma ked con as wi h i s abundance in a small a ea in
Cen e and Mi lin coun ies, in cen al Pennsyl ania, whe e du ing he
las i e win e s I ha e collec ed, o ma ked and eleased, 124 specimens.
As can be seen om he map, his a ea lies close o he geog aphical
cen e o he Leas B own Ba 's known ange.
1 Moh , Cha les E., Myo is subula us leibii and Myo is sodalis in Pennsyl ania.
Jou , o Mamm., XIII, 2, pp. 160-161, 1932. ,
2 Mille , Ge i S., J ., and Allen, Glo e M., The Ame ican ba s o he gene a
1 Myo is and Pizonyx, U. S. Na . Bull. 144, p. 172, 1928.
3 Moh , Cha les E., Pennsyl ania ba s o he genus Myo is. P oc. Pa. Acad. Sci.,
VII, p. 42, 1933.
4 Bailey, Ve non, Ca e li e o Ken ucky. Ame ican Midland Na u alis , XIV, 5,
p. 462, 1933.
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PENNSYLVANIA ACADEMY OF SCIENCE 63
Map 1. Dis ibu ion o Myo is s. leibii in U. S.
Map 2. Dis ibu ion o Myo is s. leibii in Pa.
As soon as i became appa en ha he Leas ba migh be ound
wi h some egula i y, I de e mined o ma k indi idual ba s. I used
bi d bands and ea ags* he i s yea ; bu inding ags supe io I ha e
used hem exclusi ely since hen.5 In he pas i e win e s I ha e ma ked
84 ba s, o which I ha e e aken 17, and o hese, se en we e obse ed
mo e han once, one o hem ou imes.
Obse a ions made a he ime o collec ing o ma king ba s, and
upon eco e ing ma ked ba s, lead o some in e es ing conclusions ega d-
ing he Leas B own Ba . In he i s place, i s ange in Pennsyl ania
seems ema kably es ic ed. Al hough I ha e isi ed almos 100 ca es
in Pennsyl ania and Wes Vi ginia in win e , e u ning o mos o hem
a leas once, I ha e ound he Leas B own Ba in only se en ca es.
Wi h he excep ion o Dulaney Ca e, whe e a single specimen has been
aken, all hese ca es a e loca ed in Cen e and Mi lin coun ies. Map 2
shows he p oximi y o i e o hem, Woodwa d, S o e , Rossman,
Ai kin, and Li le Ai kin ca es. Indeed a ci cle wi h a diame e o abou
22 miles would include he i e. These ca es ha bo ed 120 specimens.
The wo Ai kin ca es and S o e Ca e, which oge he con ained
o e 100 Leas ba s, a e loca ed in hea y hemlock o es s in he oo hills
o moun ains which ise o 2000 ee . The o he ca es occupied a e e y
s Moh , Cha les E., Ma king ba s o la e ecogni ion. P oc. Pa. Acad. Sci.,
VIII, pp. 26-30, 1934.
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64 PENNSYLVANIA ACADEMY OF SCIENCE
close o such a eas. The ca es a e usually small, and in he mo e ex en-
si e ca es he Leas ba s a e ound close o he en ances.
The Leas B own Ba is i alled only by he Big B own Ba , Ep esi-
cus . uscus, in i s abili y o wi hs and se e e wea he , and by i s almos
con inuous ac i i y h oughou he win e . Al hough my ca e isi s in
la e all ha e been compa a i ely in equen , I am con inced ha ew
Leas ba s en e ca es be o e he end o No embe , while o he ba s ha e
been he e o a mon h o mo e. Decembe 1, 1935, is my ea lies
eco d. In he same way hey ha e depa ed om he ca es while he
colonies o Myo is sodalis and M, I. luci ugus a e s ill qui e o pid.
Ap il 9, 1936, is my la es eco d o he Leas B own Ba ; o he species
emain in he ca es o se e al mo e weeks.
Thei a i y a ce ain imes in midwin e , and hei abundance a
o he imes only wo o h ee weeks apa sugges s ha hey may wande
ou side o he ca es du ing mode a ely wa m win e wea he , e u ning
when i becomes colde . Fo ins ance, on Ma ch 8, 1936, a e six weeks
o unusually se e e wea he , I ound abou 25 Leas ba s in S o e
Ca e, concen a ed la gely in he mos shel e ed po ions o his a he
open ca e. In Ai kin Ca e also, he Leas ba s we e a he back han
usual, i being su p ising o ind hem much mo e han 100 ee om he
en ance.
The Leas B own Ba , along wi h o he ba s/ shows a de ini e homing
sense. Ma ked ba s occu in he same ca e in di e en seasons, o i
emo ed o ano he , hey e u n o hei o iginal ca e. Fo ins ance,
#293 was cap u ed and banded a Ai kin Ca e on Ma ch 19, 1933, bu
eleased in Li le Ai kin Ca e, a qua e mile away. Du ing he ollow-
ing win e I eco e ed i h ee imes, each ime back in Ai éin Ca e.
The his o y o #310 is somewha di e en . I was cap u ed and agged
in Li le Ai kin Ca e on Feb ua y 25, 1934, and e aken he e in Ma ch
and Ap il. On Decembe 30, 1934, I isi ed Ai kin Ca e on a hu ied
nigh ip and o my su p ise ound #310 he e. I was no un il
Feb ua y, a e I had ound i again, ha I lea ned ha he en ance
o Li le Ai kin Ca e had been comple ely closed by a ock slide which
occu ed du ing he p e ious No embe . Dep i ed o i s win e oos ,
#310 hibe na ed in he nea es accessible ca e, which happened o be
Ai kin Ca e.
Li le has been lea ned ega ding he b eeding habi s o his species.
I is a soli a y species, only once ha e I obse ed a clus e , and ha
con ained only h ee indi iduals. The sexes a e equally di ided. O he
ba s examined 60 ha e been males, 64 emales; o hose agged, 33 we e
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PENNSYLVANIA ACADEMY OF SCIENCE 65
malés, 31 emales. The ac ha six males, bu ele en emales ha e been
eco e ed migh be in e p e ed as an indica ion ha he emales a e less
ac i e and possibly s ay nea e o he ca es in summe . The only known
summe eco ds a e om Sing Sing, N. Y., Plumme Island, Ma yland,
he Mammo h Ca e a ea, Ken ucky, and M . B idges, On a io. Only
he las was a emale.
Exac ly hal o he Leas ba s ound in Pennsyl ania, 62, ha e been
ound in S o e Ca e. This ca e is unique in he espec ha in i he
Leas ba s usually ou numbe all o he species. Soli a y Ep esicus /.
uscus, Pipis ellus s. sub la us, Myo is sodalis, M. I. luci ugus, and
a ely M. keenii sep en ionalis occu , bu seldom as many as hal a
dozen o any one species. In o he ca es whe e he Leas B own Ba
occu s egula ly he e a e la ge colonies o Myo is I. luci ugus o M.
sodalis . A s udy o S o e Ca e6 leads one o he belie ha he ca e
does no o e su icien shel e o he social species, bu p o ides enough
p o ec ion o he ha dy Leas B own Ba e en in he coldes wea he .
The ca e is jus abou 100 ee in ex en , 15 o 30 ee wide, 6 o 20 ee
high, and descends a abou a 45° angle. I is umo ed ha he ca e
was once qui e ex ensi e bu he ac ha he ba s a e mos nume ous in
se e e wea he indica es ha hey canno e ea beyond he known
passages.
The obse a ions he e p esen ed pe mi he ollowing en a i e con-
clusions :
1. The Leas B own Ba is limi ed in i s win e ange o e y de ini e
ecological si ua ions.
2. Ecological condi ions being a o able, his ba may occu in con-
side able numbe s.
3. This species sp eads ou du ing summe , down om he moun-
ains and he ca es in which i hibe na es.
4. E en in win e he Leas B own Ba shows conside able ac i i y,
besides showing i s ha diness by en e ing he ca es la e and
lea ing hem ea ly.
5. Indi iduals o his species win e in he same ca e yea a e
yea , as shown by he eco e y o ma ked specimens.
e S one, Ralph W., Pennsyl ania ca es, 2nd edi ion. Topog aphic and Geologic
Su ey, Ha isbu g, 1932. pp. 46-47.
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