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PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
nearby water resources, installation of bat friendly gates at sites within abandoned mines, and 
restricting human activity such as rock climbing or operation of noisy equipment near known rock 
roosts during the maternity season (Hayes and Adams, 2015). Fringed myotis will accept protec¬ 
tive gating at summer roosts in caves and mines (Currie, 2000b; Sherwin et al., 2002). In an analy¬ 
sis of the effects of bat gates on multiple species, Tobin (2016) concluded that fringed myotis con¬ 
tinued using gated mines over the long-term, tolerated various gate designs, and that the landscape 
location and structural complexity of a mine were better predictors than gate characteristics of 
whether this species would continue using a site after gating. Evidence also indicated that colonies 
of fringed myotis respond more positively to culvert gates than other mine-roosting species of con¬ 
cern that have been studied (Tobin, 2016). 
Lactating females were found to drink at water sources near their day roosts much more often 
than non-reproductive females, suggesting that loss of watering areas near roosts (as anticipated 
with global climate change) may have negative implications for population persistence (Adams and 
Hayes, 2008). Additional analysis involving mathematical models of how populations of fringed 
myotis might respond to changing climate, in both Colorado and across western North America, 
suggested that warming and drying climate conditions will cause declines (Hayes and Adams, 
2017). 
Myotis velifer — Cave myotis (Family Vespertilionidae) 
Conservation Status. — National and International Designations: U.S. Fish and Wildlife 
Service (1994, 1996a,b): Species of Concern (inactive, former Category 2 candidate for listing 
under the U.S. Endangered Species Act). Bureau of Land Management (2010a, 2011b, 2017): Sen¬ 
sitive Species (Arizona, California, Nevada state offices). International Union for the Conservation 
of Nature (2017): Least Concern. NatureServe (2017): Global Ranking G4 - Apparently Secure. 
State Designations: Arizona Game and Fish Department (2012): Species of Greatest Conser¬ 
vation Need Tier IB. California Department of Fish and Wildlife (2015b, 2017): Special Animals 
List, Species of Special Concern. Nevada Department of Wildlife (2013): Species of Conservation 
Priority. Nevada Department of 
Conservation and Natural 
Resources (2015a): Critically 
Imperiled in Breeding Range. 
Texas Parks and Wildlife (2012): 
Species of Greatest Conservation 
Need. 
Description. — The cave 
myotis (Fig. 33) is the largest 
myotis in the U.S. The forearm 
length averages about 42 mil¬ 
limeters, range 37 to 47 (Hay¬ 
ward, 1970; Hoffmeister, 1986; 
Ammerman et al., 2012a). Body 
mass of females can measure as 
high as 18.5 grams prior to hiber¬ 
nation, with a mean mass for 
males of 14.4 grams and females 
15.4 grams (Caire and Loucks, 
2010); masses at the end of 
Figure 33. Cave myotis, Myotis velifer (photo by J. Scott Altenbach). 
