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Factors influencing human hostility to King Cobras (Ophiophagus hannah) in the Western Ghats of India

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  • Kalinga Foundation
  • Centre for Herpetology/Madras Crocodile Bank Trust, India, Mahabalipuram

Abstract and Figures

This paper investigates people’s perceptions toward King Cobras in the tropical rainforests of the Western Ghats ecoregion of southern India. We built logistic regression models to test if people’s perceptions (to kill/not to kill the snake) were influenced by factors such as the snake’s size and defensiveness, whether the snake was found near human habitation, the time of encounter and season. The model correctly classified over 80% of instances when people expressed an inclination to kill the snake. Results support our expectation that the snake’s defensiveness escalates the probability that the snake will be killed, but are contrary in that smaller snakes are more likely to be killed than larger ones, especially when encountered away from human habitation. Findings suggest a need for slight refocusing of King Cobra conservation outreach efforts towards smaller snakes, especially in regions where sizeable human habitations exist near fragmented King Cobra habitat.
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Introduction
There is consensus that a variety of direct and
indirect anthropogenic stressors may be linked
to biodiversity loss worldwide (Ehrlich 1994;
Pimm et al. 1995). Although direct persecu-
tion and habitat destruction contributes more
to extinction risks in the majority of the species
(Dodd 1987; Caughley & Sinclair 1994; Bon-
net et al. 1999), intentional but non-exploitative
killing of wildlife (i.e., retaliatory killing) could
be an important but overlooked stressor (Mishra
1997; Kissui 2008; Liu et al. 2011). It is clear
that formulating conservation strategies for spe-
cies that are perceived as dangerous to humans
can be difcult given the need to balance human
and wildlife welfare. This is especially true for
snakes, against which humans harbor deep-seat-
ed prejudices (Ohman & Mineka 2003; Prokop
et al. 2009; Fita et al. 2010; Prokop & Fancovi-
cova 2010).
From a biological standpoint, studies have
identied combinations of behavioral and life-
history traits and seasonal factors that affect
mortality patterns in snakes. Reed & Shine
(2002) found extinction risk in Australian elapid
snakes to be related to foraging habit and com-
bat behavior wherein ambush predators and
snakes that do not engage in male-male combat
were at a higher risk of extinction. Bonnet et
al. (1999) found that snakes that dispersed over
long distances were more at risk than their more
sedentary conspecics, and were more likely to
be killed during the mating season. Although a
number of studies have investigated patterns of
Hamadryad Vol. 36, No. 2, pp. 91 – 100, 2013.
Copyright 2013 Centre for Herpetology, Madras Crocodile Bank Trust.
Factors inuencing human hostility
to King Cobras (Ophiophagus hannah)
in the Western Ghats of India.
P. Gowri Shankar1*, Aditya Singh2, S. R. Ganesh3 and Romulus Whitaker4
1 No. 14/60, Shakthinagar, Behind TTK, Dooravaninagar Post,
Bangalore, Karnataka 560 016, India
2 Department of Forest and Wildlife Ecology, University of Wisconsin-Madison,
1630 Linden Dr., Madison, Wisconsin 53706, USA
3 Chennai Snake Park, Rajbhavan post, Chennai, Tamil Nadu, India
4 Agumbe Rainforest Research Station, Suralihalla, Agumbe, Thirthahalli Taluk,
Shivamogga District - 577411, Karnataka, India
*Corresponding author, Email: gowrishankar.pogiri@gmail.com
ABSTRACT.– This paper investigates people’s perceptions toward King Cobras in the tropical
rainforests of the Western Ghats ecoregion of southern India. We built logistic regression
models to test if people’s perceptions (to kill/not to kill the snake) were inuenced by
factors such as the snake’s size and defensiveness, whether the snake was found near
human habitation, the time of encounter and season. The model correctly classied over
80% of instances when people expressed an inclination to kill the snake. Results support
our expectation that the snake’s defensiveness escalates the probability that the snake
will be killed, but are contrary in that smaller snakes are more likely to be killed than
larger ones, especially when encountered away from human habitation. Findings suggest
a need for slight refocusing of King Cobra conservation outreach efforts towards smaller
snakes, especially in regions where sizeable human habitations exist near fragmented
King Cobra habitat.
KEYWORDS.– Agumbe, ARRS, King Cobra, logistic regression, mortality risk.
Shankar.indd 91 03-07-2013 05:57:27
92 Hamadryad [Vol. 36, No. 2
human-caused mortality in snakes (Bonnet et
al. 1999; Lode 2000; Whitaker & Shine 2000;
Akani et al. 2002; Ciesiolkiewicz et al. 2006),
most have focused on factors inuencing indi-
rect or accidental mortality, such as via vehicu-
lar accidents. For example, Row et al. (2007)
estimated road mortality to cause an increase in
extinction probability from 7.3% to 99% over
500 years for black rattlesnakes in Ontario, Can-
ada. Whereas estimates for intentional anthro-
pogenic mortality are generally rare (Bonnet et
al. 1999), Akani et al. (2002) could attribute ca.
50% of cases of snake mortality to intentional
killing by humans in the Niger Delta. Akani
et al. (2002) also found a signicant seasonal
pattern to snake encounters in human habitat
wherein most events were related with rainfall
events that forced snakes from their natural ref-
uge to places inhabited by humans.
From the human standpoint, negative percep-
tions of snakes are believed to have evolution-
ary roots (Ohman & Mineka 2003) and have
been observed as behavioral manifestations
across countries and cultures (Prokop et al.
2009; Fita et al. 2010). As a result, conservation
programs focused on snakes have to deal with
two distinct issues: 1) patterns of snake behav-
ior that put snakes in direct contact with humans
and, 2) overcoming inherent human responses
to encounters with snakes that make outreach
and sensitization difcult. Sensitization is es-
pecially difcult when the species involved are
venomous and easily identied as such. The is-
sue is further compounded in developing coun-
tries where large human populations exist in
close proximity to wildlife habitat and where
the largest number of cases of envenomation
occur (Harrison et al. 2009). Factors that affect
the ability of snakes and humans to cohabitate
are therefore important both from snake conser-
vation and human welfare standpoints. This is
especially important for a mega diverse country
like India that reports a disproportionate number
of snake envenomation cases globally (mortal-
ity estimates ranging widely from about 1300 to
50 000; Mohapatra et al. 2011)
Figure 1. Location of Agumbe (○) in the Western Ghats of South India overlaid on a terrain-shaded map. Loca-
tions where encounters were reported from are shown as lled circles (●).
Shankar.indd 92 03-07-2013 05:57:27
June, 2013] Human Hostility to King Cobras 93
The focus of this study, the King Cobra
(Ophiophagus hannah, Cantor 1836) is the larg-
est venomous snake in the world (Tin-Myint et
al. 1991; Das 1996; Whitaker & Captain 2004;
Inger et al. 2009). Largely diurnal, the snake
can reach up to 5.5 m in length, feeds mainly on
snakes, is oviparous, and is the only snake that
builds a nest (Aagaard 1924; Smith 1943; Whi-
taker 1978; Daniel 2002; Whitaker & Captain
2004). Classied ‘Vulnerable’ by the IUCN (In-
ger et al. 2009), King Cobras are mostly found
in and around the tropical rainforests of India,
southern China and southeast Asia. They also
inhabit a variety of microhabitats such as man-
grove swamps, agricultural elds, and have been
reported from degraded semi-evergreen and de-
ciduous forest fragments in India. Although data
on population trends of King Cobras in India are
insufcient, it is thought that continuing habitat
destruction and degradation may be negatively
inuencing their numbers (Inger et al. 2009).
Although many communities in India consid-
er snakes (especially cobras, Naja spp.) sacred
due to religious beliefs (Joshi & Joshi 2010),
King Cobras are often killed when they come
in contact with humans. Although the exact rea-
sons are unknown, King Cobras in the region
likely enter human habitations to seek other
snakes (their major prey), which in turn, are
probably attracted to a higher relative density
of rodents around agricultural elds and house-
hold granaries. Human reactions to King Cobra
encounters in India and elsewhere may be a
complex combination of societal and situational
factors. Such factors could include the behavior
of the snake (i.e., level of defensiveness), the
location where the snake is encountered (e.g.,
inside sleeping quarters of a dwelling), seasonal
factors (such as during monsoons when burrows
used as refuge by snakes are ooded, and during
the mating season) or socio-cultural factors (re-
ligious beliefs, levels of formal education, prior
exposure to sensitization).
This study investigates factors inuencing
people’s perceptions (intention to kill, or leave a
snake alone) in events of encounters with King
Cobras in and around villages situated in tropi-
cal rainforests in southern India. We hypoth-
esize that 1) people would be more hostile to
highly defensive snakes, as a highly defensive
snake may pose a greater immediate danger to
people in the vicinity; 2) people would be more
hostile to larger and healthier snakes, as a large
(and healthy) snake could be perceived as more
dangerous with respect to quickness, strength
and perceived venom delivery than a smaller (or
sicker) one; 3) people would be more inclined to
kill a snake when encountered inside or near hu-
man habitation because of the perceived direct
danger posed to humans and 4) people would be
more inclined to kill a snake when encountered
in the dark, as darkness could be perceived to
confer an elevated opportunity to the snake to
either escape or evade detection. Although so-
cietal and/or educational factors may strongly
inuence people’s perceptions, we do not cur-
rently have data on socio-economic or cultural
factors.
We believe that information on what shapes
people’s reactions to King Cobra encounters
could be invaluable from both public welfare
and management standpoints. Such information
could aid King Cobra conservation by improv-
ing management of snake-human encounters,
as well as for retooling conservation, education
and rst-response strategies. To the extent of our
knowledge, this is the rst study of its kind in
the Indian subcontinent.
Material and Methods
Study area.– Agumbe is situated in a reserve
forest in the Western Ghats Ecoregion of In-
dia (13°30’15” E, 75°5’25” N, Fig.1). The re-
gion harbors high levels of biodiversity, much
of which is endemic. Not only is the Western
Ghats ecoregion a global biodiversity hotspot
(Mittermeier et al. 1998; Myers et al. 2000; My-
ers 2003) it was also recently designated a UN-
ESCO World Heritage Site (UNESCO 2012).
The physiography consists of forested hills,
tropical evergreen rainforest (Champion & Seth
1968; Ramaswamy et al. 2001) and oodplains
characterized by a mosaic of agriculture (paddy)
and plantations (areca, coconut, plantain, aca-
cia). The region is one of the wettest regions in
southern India and receives an annual rainfall
of ca. 8000 mm during the southwest monsoon
(June–September). Terrain elevation ranges
from 150 m to 800 m.
Data collection.– A research program initiated
by the Agumbe Rainforest Research Station
(hereafter ARRS) has been monitoring human-
Shankar.indd 93 03-07-2013 05:57:27
94 Hamadryad [Vol. 36, No. 2
King Cobra encounters since 2005. Data for
this study were collected over a ve-year period
from 2005–2009. The ARRS conducts long-
term ecological research into the biology of
the King Cobra as well as provides educational
and outreach programs to village communities
in the region. The outreach program at ARRS
has ensured that most, if not all, King Cobra-
human encounters are immediately reported and
responded to. For each ‘rescue’ call received at
the ARRS, a team comprised of a trained snake
catcher and community outreach specialists
were immediately dispatched. On arrival, the
team evacuated all people from the immediate
location and outreach specialists conducted a
semi-structured interview of the rst responders
and the owners of the property. Outreach spe-
cialists also delivered a comprehensive “snake-
talk” to people present at the location. In the
meantime, the snake rescue specialist safely
captured the snake using hooked sticks and cloth
bags (Fig. 2, following the protocol by Whitak-
er 1970). The rescue specialist took length and
weight measurements to the nearest centimeter
and gram respectively, determined its gender,
deposited it in custom-made bags, and prepared
it to be safely released in a forested region at
least a kilometer away from the capture locality.
A brief health assessment of the snake was also
carried out. We termed the health
‘good’ when the snake had a more
or less circular body cross section
and the vertebral column not visible
through the skin, ‘moderate’ when
the snake had a more or less round
body with slightly evident vertebral
column and ‘poor’ when the snake
had a tented body with the vertebral
column and rib bones easily visible.
For each such call, details of the
physical environment and the (pre-
capture) opinion of the responders
towards either killing or not killing
the snake were also recorded.
The behavior of the snake was
assessed by taking into considera-
tion the objective opinion of the
rst responders, and by observa-
tions made by the team before the
rescue commenced. The behavior
was judged ‘very defensive’ when
the snake reared up hooded, hissed and charged
when rst approached; ‘defensive’ when the
snake reared up hooded, hissed and charged
once disturbed during capture; ‘moderate’ when
the snake showed moderate resistance to han-
dling and ‘docile’ when the snake did not ex-
hibit any signs of vigorous resistance during the
course of rescue.
Statistical analysis.– As the response of re-
sponders (intention to kill/ not kill) was best
modeled as a binary (1/0) choice, we built logis-
tic regression models to model the response as
a function of the variables: snake defensiveness
(categorical: ve levels: very defensive to very
Table 1. Number of total King Cobra rescue calls (2005–2009) received
at ARRS, cross-tabulated by location where snake was encountered.
Rescue calls in the breeding season are shown in bold typeface.
Month Field House Forest Plan-
tation Settle-
ment Total
Jan 4 7 11
Feb 3 6 1 10
Mar 12 9 3 3 2 29
Apr 3 2 1 6
May 1 6 1 1 9
Jun 1 3 1 5
Jul 1 5 6
Aug 2 1 4 1 8
Sep 1 4 1 2 8
Oct 2 1 1 1 5
Nov 3 3 6
Dec 1 2 3
Total 30 48 12 9 7 106
Figure 2. An adult King Cobra being rescued from a
well near Agumbe. Photo P. Gowri Shankar.
Shankar.indd 94 03-07-2013 05:57:27
June, 2013] Human Hostility to King Cobras 95
Figure 3. Surface plots showing the probability that a snake would be killed (on the z-axis) as a function of snake
length (y-axis: min = 55cm, max = 400cm.) and time-of-day (x-axis; extremes denote midnight, axis midpoint
denotes midday). Note: the z-axis is scaled from 0 to 1 in all subplots, probabilities are symmetric about the
midpoint of the time (x) axis. Subplots grouped by combinations of whether a snake was defensive (subplot a,
c) or docile (subplot b, d); if it was found in human habitation (subplot a, b) or in an open area (subplot c, d).
the snake was excluded as a predictor as none of
the interviewees could give consistent guesses
on the gender of the snake, and it likely did not
inuence their eventual perception. We sequen-
tially tested all main and all possible two-way
interaction effects between all variables for sig-
nicance. We sequentially dropped all non-sig-
nicant effects until only signicant interaction
effects and associated main effects remained.
Preliminary analyses revealed that defensive-
ness was better modeled as a binary variable
docile), health (categorical: three levels; bad,
moderate, good), month (categorical), snake
size (length in cm.), location (binary, near or
inside house, well, shed or granary = 1, 0 else-
where) and time of encounter (sine-transformed
to scale midday to 1.0 and midnight to -1.0). We
did not use the snake’s mass as a proxy for size
because 1) mass is highly correlated with length
and 2) people would most likely nd it easier to
estimate length as opposed to mass as a proxy
for size. Being a perception study, the gender of
Shankar.indd 95 03-07-2013 05:57:28
96 Hamadryad [Vol. 36, No. 2
and was thus recoded as such (very defensive or
defensive = 1, moderate or docile = 0). Because
the snake’s defensiveness could be a major fac-
tor determining public perception, we separate-
ly modeled the snake’s defensiveness as a func-
tion of size, month (or March = 1 as a binary
variable denoting the end of breeding season),
time of day and location. Finally, we used Mo-
ran’s I (Moran 1950) to test for spatial autocor-
relation in standardized residuals from the nal
model. All statistical analysis was conducted
using SAS software, Version 9.2 (SAS System
for Windows © 2002–2008, SAS Institute, Inc.
Cary, North Carolina, USA).
Results
A total of 107 rescue calls were attended to be-
tween 2005 and 2009 (mean: 21 ± 7SD Year-1).
The maximum number of rescues were conduct-
ed in 2006 (N = 29) and 2009 (N = 28). Report-
ing patterns did not follow any predictable trend
across years (P > 0.1). Across months however,
rescue calls increased signicantly in post-win-
ter months (Jan–March mean: 16.66 ± 10.69
SD) in comparison to the rest of the year (Apr-
Dec: mean: 6.33 ± 1.87 SD, P < 0.001). Rescue
calls peaked in March, when
there were approximately
seven times as many rescues
as the annual average (mean
excluding March: 7.09 ± 2.3
SD). It should be noted that
the breeding season for King
Cobras starts around Janu-
ary, peaks in March, and culminates with
hatching of the young near late July or
early August. As expected, the majority
of snakes were reported from around hu-
man habitation (88.68% in any human
use area, 45.28% of total inside houses,
Table 1). Although no trend was apparent
for non-breeding months, a large major-
ity of the calls during the early breeding
season (Jan–Feb) involved snakes en-
countered in houses (>60%) and in ag-
ricultural elds or plantations in March
(~40%). Around 80% of the snakes were
found in good health, and on average
measured 297.05 ± 6.38 cm in length
(N = 107, range: 55.5–396.24 cm) and
weighed 4464.54 ± 286.03 g (N = 63,
range: 22–12 000 g). Responders expressed an
inclination to kill the snake in only 14% of the
cases.
We used a complementary log-log link func-
tion to t the logistic regression model as re-
sponse proportions were skewed (14% kill, 86%
not kill). One observation did not have sufcient
information on covariates and was dropped from
all subsequent analyses. After removing all non-
signicant effects, the logistic regression model
retained only four variables (Table 2), and cor-
rectly classied 83.8% of all instances where
people wanted the snake killed. The main effect
of the variable coding for human habitation was
signicant (P = 0.002) as were the interaction
effects of length of snake and defensiveness (P
= 0.001), and the time of day and defensiveness
(P = 0.02). Tests for spatial autocorrelation in re-
siduals were not signicant (Moran’s I, P > 0.1)
indicating no signicant spatial clustering in
public perceptions and encounter reporting pat-
terns. As independent examination of individual
variables was difcult due to the presence of
two interaction effects, we built ‘kill-probabil-
ity’ response surfaces by segmenting the model
by the categorical variables ‘habitation’ and ‘de-
Table 2. Results from a logistic regression model investigating
factors affecting people’s opinions (kill = 1, not kill = 0) on
encounters with King Cobras in the Western Ghats of India (n
= 106, Wald χ2 = 19.28, df = 6, P < 0.0037). The model used
a complementary log-log link function. The model correctly
classied 83.8% of all cases where people wanted to kill Co-
bras (AUC = 0.839).
Parameter df βS.E. P
Intercept 1 0.607 1.670 0.7160
Defensive 1 6.129 2.056 0.0029
Length (cm) 1 -0.008 0.005 0.1672
Length*defensive 1 -0.026 0.007 0.0004
Habitation 1 -1.890 0.535 0.0004
Time 1 1.227 0.983 0.2122
Time*defensive 1 2.613 1.006 0.0094
Table 3. Results from logistic regression investigating factors affecting
King Cobra defensiveness (Wald χ2 = 10.63, df = 1, P < 0.01). The model
correctly classied only 37.7% of all cases where King Cobras displayed
defensive behavior (AUC = 0.656).
Parameter df βS.E. P
Intercept 1 -0.715 0.255 0.005
Breeding season 1 1.757 0.539 0.001
Shankar.indd 96 03-07-2013 05:57:28
June, 2013] Human Hostility to King Cobras 97
fensiveness’ and by varying continuous predic-
tors (length of snake and time of day) across the
range of the respective measurements.
Results indicate that defensive snakes (Fig
3a, 3c) are at a disproportionately higher risk
of being killed than their relatively docile coun-
terparts (Fig 3b, 3d) regardless of whether they
are encountered around habitation or in open ar-
eas. Also, smaller snakes are more likely to be
killed than larger ones regardless of the snake’s
level of defensiveness or the location where the
snake is encountered. Results also indicate that
the probability a snake will be killed is generally
higher during the day than in the night (Fig 3). A
logistic regression model built to explain snake
defensiveness retained only ‘month = March’ as
a signicant explanatory variable but explained
only 37.7% of all cases where the snake was
found defensive (Table 3).
Discussion
Our intent was to investigate factors that inu-
ence people’s opinions on harming King Cobras
when encountered in and around human habita-
tion. A logistic regression model relating situa-
tional factors with people’s opinions successful-
ly predicted over 80% of all cases where people
wanted the snake killed rather than left alone.
In spite of the apparent good t of the model,
it should be noted that this study is limited to
situations when rescue calls are actually made,
it may well be that a larger number of snakes
are killed (often of the genus Naja) and never
reported back to the conservation team.
While our expectation that defensive snakes
would attract more hostile reactions was sup-
ported by the data we collected, none of the
other hypotheses were supported. Specically,
when controlling for the size of the snake and
the location of encounter, the model conrmed
that defensive snakes were far more likely to be
killed than ones that were relatively docile. In
contrast, for the second hypothesis (larger snakes
would be more at risk) the model suggested the
opposite. We found that smaller snakes were far
more likely to be killed than larger ones across
all levels of defensiveness and location of the
encounter. While this nding is counterintuitive,
we suspect that elevated hostility of people to-
wards smaller King Cobras may be related to
the higher apparent likelihood of successfully
subduing an ‘aggressive’ but smaller-sized and
identiably dangerous snake. We speculate that
it is likely traditional knowledge in the region
that the young of the King Cobra hatch with
enough venom to cause mortality in humans.
Elevated defensiveness in younger King Cobras
has been observed in the eld, and has also been
widely reported for a number of other species
(for example, see Brodie & Russell 1999; Shine
et al. 2002). Our expectation that people would
be more hostile towards snakes found in and
around habitation was also not supported by the
data. We found that snakes encountered in the
open were signicantly more likely to be killed
than left alone. This nding indicates a poten-
tially elevated mortality risk for King Cobras
around forest edges and fragments. Whereas
the model showed a signicant time-of-day ef-
fect, in that people would likely want to have
the snake killed when encountered during day-
time, we suspect this may be an artifact of the
confounding effects of the diurnal nature of the
King Cobra coinciding with general activity
patterns of humans. In combination, discounting
time-of-day as a confounding factor, the model
suggests the possibility of the ‘ease of subduing’
hypothesis to be the leading factor shaping peo-
ple’s perceptions in typical King Cobra encoun-
ters. It is likely that smaller snakes are more
likely to be killed when encountered in areas
where they can be tracked and pursued easily,
especially when they display elevated defensive
behavior.
The only factor that was a signicant pre-
dictor for snake defensiveness was the binary
variable coding for the month of March. This
may indicate a seasonal pattern to snake defen-
siveness related to breeding and nesting phe-
nology of King Cobras. In general, defensive-
ness in snakes has been related to antipredator
behavior (in this case, likely a response to hu-
mans, also see: Bonnet et al. 2005; Aubret et
al. 2011), seasonal weather patterns (Schieffe-
lin & Dequeiroz 1991; Brodie & Russell 1999;
Mori & Burghardt 2004), reproductive status
(Brodie & Russell 1999; Brown & Shine 2004)
and body condition (Shine et al. 2000; Shine et
al. 2002). Although we currently do not have
data to test these theories specically for the
King Cobra, they are a subject of ongoing re-
search at ARRS.
Shankar.indd 97 03-07-2013 05:57:28
98 Hamadryad [Vol. 36, No. 2
From a conservation standpoint, the nding
that smaller snakes are more likely to be killed
could lead to the possibility of a population bot-
tleneck occurring, especially if increasing habi-
tat degradation and fragmentation drives more
snakes into human habitation. Increased inten-
tional anthropogenic mortality may pose an
additional stressor to King Cobra populations
when compounded with persecution from do-
mesticated mesopredators (such as dogs, pigs)
around forest edges. Further, such direct anthro-
pogenic stressors may aggravate reproductive
losses King Cobras suffer from nest-raiding
mesopredators such as monitor lizards (Varanus
spp.) and mongooses (Herpestes spp.).
From a human welfare and conservation
standpoint, the ndings point to a need for a
slight retuning of outreach focus. Although the
current outreach program has focused on edu-
cating people on the ecological importance of
snakes in general, the focus on protecting small-
er snakes could probably be emphasized. There
is also the possibility of implementing sensitiza-
tion programs and classes to train affected peo-
ple in the safe handling of smaller snakes for
removal from houses. Overall, these ndings
could be utilized to design better conservation
and outreach strategies in India; and perhaps in
other regions with extant King Cobra popula-
tions.
Acknowledgements
We thank Brijesh Kumar, Conservator of For-
ests, N.B. Manjunath, Assistant Conservator of
Forests, N.H. Jaganath and H.S. Suresha, Range
Forest Ofcers for their support and B.K. Sin-
gh, Principal Chief Conservator of Forests and
Chief Wildlife Warden (Wildlife) Karnataka
State Forest Department for research permits.
We are thankful to Prashanth, Sharmila Rajase-
garan and all other staff of Agumbe Rainforest
Research Station (ARRS) for their kind cooper-
ation. We are grateful to the public who cooper-
ated with us whenever King Cobras entered into
their properties. Thanks are also due to Nikhil
Whitaker, Gowri Mallapur and all other staff of
Madras Crocodile Bank/Centre for Herpetol-
ogy for their help in literature collection. We
thank Matt Goode and an anonymous reviewer
for comments that greatly improved the manu-
script. AS was supported by a graduate assistant
fellowship from the Department of Forest and
Wildlife Ecology at the University of Wiscon-
sin-Madison, and would like to thank Philip
Townsend for his help and support for this re-
search. We thank the National Geographic So-
ciety (King Cobra Telemetry Project), National
Geographic Television (ARRS) and the Whitley
Fund for Nature (ARRS) for their generous -
nancial support of the Agumbe Rainforest Re-
search Station.
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... Despite this fear, some respondents indicated that snakes are important to the environment (Pandey et al. 2016;Marshall et al. 2018;KD, manuscript). Shankar et al. (2013) reported that people were more likely to kill snakes when encountered during the day. In this study, we also found that the majority of King Cobras were killed during daytime, which likely reflects the diurnal nature of both humans and King Cobras . ...
... Landscape fragmentation results in smaller, more isolated patches, which can result in population-level changes to native flora and fauna. King Cobras are considered an apex predator Marshall et al. 2018) that feeds mainly on a variety of snakes (Bhaisare et al. 2010;Barve et al. 2013;Shankar et al. 2013;Marshall et al. 2018) and occasionally on monitor lizards (Varanus spp.; Shankar et al. 2013;Marshall et al. 2018). Existing protected areas are likely not adequate to mitigate against anthropogenic mortality Marshall et al. 2018) because King Cobras can move long distances leaving protected areas, which places them at higher risk of encountering humans (Thapa et al. 2019). ...
... Landscape fragmentation results in smaller, more isolated patches, which can result in population-level changes to native flora and fauna. King Cobras are considered an apex predator Marshall et al. 2018) that feeds mainly on a variety of snakes (Bhaisare et al. 2010;Barve et al. 2013;Shankar et al. 2013;Marshall et al. 2018) and occasionally on monitor lizards (Varanus spp.; Shankar et al. 2013;Marshall et al. 2018). Existing protected areas are likely not adequate to mitigate against anthropogenic mortality Marshall et al. 2018) because King Cobras can move long distances leaving protected areas, which places them at higher risk of encountering humans (Thapa et al. 2019). ...
Article
Full-text available
Snake research tends to have a low priority in Nepal and very little information, mostly confined to populations in small areas, addresses the biology and threats to the King Cobra (Ophiophagus hannah). Herein we provide data that could facilitate an assessment of the species’ status in Nepal and begin to address its conservation needs. We recorded data on King Cobras from 2015–2020, cross-checking with previous studies to avoid any duplication of records. A King Cobra from Siddhara, Arghakhachi District, was the first record of the species in the district. We recorded a total of 50 King Cobra mortalities from 20 districts, with most of them killed near human settlements adjacent to forested areas. We mapped the locations of all mortalities and recorded land-use changes within a 500-m buffer around each site over a 30-year period (1990–2020), revealing extensive landscape fragmentation in previously connected natural areas. Our data suggest that the major threats to King Cobras are deliberate killing by humans and large-scale habitat loss due to an increasing human population. We recommend increased research to better understand the biology of this charismatic species and continued conservation education and community outreach programs to facilitate the development of effective conservation strategies.
... Vulnerability in anthropogenic landscapes can be augmented by traits such as large body size, parental investment in offspring, habitat specialisation, and low population densities, all of which have been connected to increased extinction risk [19][20][21][22][23]. Species frequently involved in human-wildlife conflict are also more vulnerable to direct mortality in anthropogenic landscapes [24][25][26]. ...
... For example, road crossing structures in combination with fencing would likely help to mitigate the threat posed by roads [112]. Whereas reducing persecution of King Cobras will require a change in current negative perceptions [24,25] and improvements in humane snake removal services, although the cost-effectiveness of snake removal services needs further quantitative study [113]. ...
Article
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Background Studying animal movement provides insights into how animals react to land-use changes. As agriculture expands, we can use animal movement to examine how animals change their behaviour in response. Recent reviews show a tendency for mammalian species to reduce movements in response to increased human landscape modification, but reptile movements have not been as extensively studied. Methods We examined movements of a large reptilian predator, the King Cobra (Ophiophagus hannah), in Northeast Thailand. We used a consistent regime of radio telemetry tracking to document movements across protected forest and adjacent agricultural areas. Using dynamic Brownian Bridge Movement Model derived motion variance, Integrated Step-Selection Functions, and metrics of site reuse, we examined how King Cobra movements changed in agricultural areas. Results Motion variance values indicated that King Cobra movements increased in forested areas and tended to decrease in agricultural areas. Our Integrated Step-Selection Functions revealed that when moving in agricultural areas King Cobras restricted their movements to remain within vegetated semi-natural areas, often located along the banks of irrigation canals. Site reuse metrics of residency time and number of revisits appeared unaffected by distance to landscape features (forests, semi-natural areas, settlements, water bodies, and roads). Neither motion variance nor reuse metrics were consistently affected by the presence of threatening landscape features (e.g. roads, human settlements), suggesting that King Cobras will remain in close proximity to threats, provided habitat patches are available. Conclusions Although King Cobras displayed individual heterogeneity in their response to agricultural landscapes, the overall trend suggested reduced movements when faced with fragmented habitat patches embedded in an otherwise inhospitable land-use matrix. Movement reductions are consistent with findings for mammals and forest specialist species.
... It has already been suggested that public education and human welfare may be the best approach for successfully achieving conservation goals (Shankar et al., 2013). In 2020, however, the Sustainable Development Goals (SDG) meeting of the United Nations summarized the failure of all 20 SDGs (United Nations, 2020). ...
Thesis
Im Fokus dieser Dissertation steht die Zerstörung des Lebensraumes von Schlangen durch anthropogene Einflüsse im Zusammenhang mit dem Auftreten von Schlangenbissen bei Menschen. Zum Schutz der Schlangen und dem Problem der Schlangenbisse wurden vier wesentliche Anforderungen erarbeitet. Mit Hilfe eines Artenverteilungsmodells wurden die ökologischen Nischen von 29 Giftschlangenarten aus Bangladesch und von zehn Kobraarten (Naja) aus Asien ermittelt. Auf lokaler Ebene wurde festgestellt, dass Überschwemmungen, Waldtypen, Ökosysteme und klimatische Parameter das Verbreitungsgebiet der Schlangenarten in Bangladesch beeinflussen. Auf regionaler Ebene sind anthropogene Faktoren wie die Zerstörung von Schlangenlebensräumen, Handel, Ausbeutung und Tötung von Schlangen wahrscheinlich die Hauptursachen für den Rückgang der Populationen der asiatischen Naja. Auf beiden Ebenen führt der Klimawandel zu einer Verkleinerung der ökologischen Nischen von Schlangenarten in Bangladesch und Asien. In Bangladesch könnten die untersuchten Arten innerhalb der nächsten 50 Jahre mehr als 90 % ihren derzeitigen Lebensraum verlieren (Asiatische Naja durchschnittlich 56 % (12 bis 100 %)). Wenn günstige Nischen nicht erhalten werden können, könnten viele Schlangenarten in einigen Ländern Asiens, darunter Bangladesch, in wenigen Jahrzehnten aussterben. Darüber hinaus wurde in der vorliegenden Studie geschätzt, dass die Zahl der jährlichen Schlangenbisse in Bangladesch mehr als doppelt so hoch sein könnte wie bisher angenommen. Da der Klimawandel zu einer geografischen Verschiebung günstiger Nischen führen kann, kann sich diese Veränderung auch auf die Häufigkeit von Schlangenbissen auswirken. Bei der Analyse von Giftvariationen und der Wirksamkeit von Antivenomen wurde festgestellt, dass isolierte Populationen deutliche intraspezifischere Giftvariationen zeigen.
... Destruction of habitats, illegal trade, and persecution by humans are the primary conservation threats to the king cobra (Stuart et al., 2012;Shankar et al., 2013;Marshall et al., 2018). Consequently, the species is considered to be declining throughout its range and is currently listed as "vulnerable" (VU) on the IUCN Red List (Stuart et al., 2012); placed in Appendix II by CITES; and is in Schedule II of the Indian Wildlife Protection Act (1972). ...
Article
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We collect threatened nests with eggs, juveniles and adult females of vulnerable king cobra (Ophiophagus hannah) from various parts of Mizoram, north-east India. Eggs were incubated, then juveniles and rescued adults were released in the protected areas. At present, this is the only conservation strategy that can be applied in the region.
... Extension of protected areas over climatically suitable space may ensure uninterrupted habitats for cobras to withstand human pressure 10 . It has already been suggested that public education and human welfare may be the best approach for successfully achieving conservation goals 53 . In 2020, however, the Sustainable Development Goals (SDG) meeting of the United Nations summarized the failure of all 20 SDGs 54 . ...
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Asian cobras (genus Naja ) are venomous snakes distributed from the Middle East to Southeast Asia. Because cobras often live near humans settlements, they are responsible for a large part of snakebite incidents and as such pose a challenge for public health systems. In the light of growing human populations, correctly mapping the present and future ranges of Asian cobras is therefore important for both biological conservation and public health management. Here, we mapped the potential climatic niches of ten Asian cobra species for both the present and the future, with the aim to quantify changes in climate and human population densities relative to their current and future ranges. Our analyses reveal that cobras that are adapted to dry climates and inhabit islands have narrow climatic niches, while those of mainland species with larger geographic ranges are much wider. We also found a higher degree of fragmentation of future cobra distributions; within the next 50 years, Asian cobras will lose an average of around 60% of their current suitable climatic range. In the near future, Naja mandalayensis , N. sputatrix , N. samarensis , and N. philippinensis are likely to have no accessible suitable climate space left. Besides, a further increase of human populations in this region may also exponentially accelerate the effects of anthropogenic impacts. Solutions for conservation may involve awareness and appropriate use of law to overcome the rate of habitat degradation and the increase of animal trade of Asian cobras, while promoting investment on health systems to avoid snakebite fatalities.
... According to Roskraft et al. (2003), those people living in an area where carnivores exist tend to be less fearful than those who do not encounter them. In the case of King cobras, they have the more tendency to be killed by humans when they escalated defensiveness (Shankar et al. 2013). While the probable reason for dislike and fear of snakes of the respondents may be due to their lack of personal encounters, negative personal experience may escalate a negative attitude even more. ...
Article
Full-text available
Snakes, being less charismatic and infamous among threatened wildlife, are usually given biased treatment for conservation. Hence, the study on knowledge, attitudes, perception, and actions of 264 university students toward Philippine snakes was conducted on Caraga State University's main campus. The survey questionnaire consisted of four parts: socio-demographics, knowledge (snake identification), attitudes and perception toward snakes, and their source of information. A point bilateral correlation test was used to determine the association of knowledge and attitude and knowledge with information sources. Association of attitudes with sources of information and the inter-attitudinal association was determined via Fisher’s Exact Test. Results showed that most students lack knowledge of snake species, having a mean score of 2.2 out of ten. Despite the low score observed, students tend to have positive attitudes towards snakes. The majority (86%) of the respondents favored the conservation of the taxa, despite the perceived fear (81%) and dislike for snakes (83%). The students’ perception also demonstrated considerable awareness with regards to the ecological role of snakes. Meanwhile, TV news (81%) and school (60%) were the most identified sources of information, while social media, family, and documentary were positively associated with the students’ knowledge of snakes. Information from this study would be essential in the formulation of efficient management plans and conservation for snakes in the Philippines, particularly in the Caraga region.
... B. Whitaker & Shine, 2000). Human predisposition to kill snakes adds additional sources of mortality for snakes occupying human-dominated areas (Akani et al., 2002;Bailey, Campa, Harrison, & Bissell, 2011;Meek, 2012;Pandey et al., 2016;Shankar, Singh, Ganesh, & Whitaker, 2013;P. B. Whitaker & Shine, 2000;Wolfe, Bateman, & Fleming, 2017). ...
Article
Full-text available
Protected areas are often promoted as an important solution to preserving biodiversity. However, permeable edges can undermine the effectiveness of preserves because animals may move into adjacent human-dominated unprotected areas. We investigated attitudes toward, and sources of mortality of, a far-ranging apex predator, the king cobra (Ophiophagus hannah; Cantor 1836), in a biosphere reserve in northeastern Thailand. Our questionnaire revealed marked fear of snakes and hostility toward king cobras. Using radiotelemetry, we followed 23 king cobras over a 4-year period, during which time we documented the mortality of 14 individuals. We considered 10 of the deaths to be anthropogenic in origin, including road mortality, pollution, fish traps, and direct persecution; these deaths disproportionately occurred in unprotected areas. Our results highlight how dangerous human-dominated landscapes are for king cobras. Because king cobras move long distances and maintain large home ranges, it is likely that successful conservation of the species cannot be satisfactorily met by protected areas alone; a more holistic, education-focused conservation strategy is required. We stress the importance of a human dimensions approach that leads toward greater understanding of human attitudes toward king cobras, and snakes in general, combined with ecological research for more effective conservation.
... Despite not showing active preference for forest, adult males tended to use protected forested areas, which may be due to a number of reasons, including access to mates (Duvall and Schuett, 1997;Jellen et al., 2007), increased prey abundance (Baxley and Qualls, 2009), greater opportunities for thermoregulation (Carfagno, Heske and Weatherhead, 2006), increased number of shelter sites (Whitaker and Shine, 2003), and protection from human persecution (Shankar et al., 2013b). The lack of preference expressed means that the use of forests can be somewhat accounted for by its availability. ...
Article
A species’ spatial ecology has direct implications for that species’ conservation. Far-ranging species may be more difficult to conserve because their movements increase their chances of encountering humans. The movements can take them out of protected areas, which is especially risky for species that are routinely persecuted. The king cobra (Ophiophagus hannah), a large venomous elapid, is subject to anthropogenic pressures, such as persecution and habitat loss. Here we present results from a study using radio telemetry to quantify movements and habitat use of nine king cobras in and around a protected area in Northeast Thailand. This study is the first investigation into the movements and habitat use of king cobras outside of the Western Ghats, India. On average, the tracked king cobra’s use areas of 493.42 ± 335.60 ha (95% fixed kernel), moving 183.24 ± 82.63 m per day. King cobras did not remain in intact forested area. Five of the individuals frequently used the human-dominated agricultural areas surrounding the protected area, appearing to make regular use of irrigation canals. Two adult males showed increases in movements during the breeding season. One male’s increased breeding season range caused him to venture beyond the protected area, shifting his habitat use from intact forests to scrub in human-dominated areas. King cobras’ large home range and willingness to use anthropogenic landscapes merits special consideration from conservation planners.
... Ecosystem engineers such as spiny tailed lizards (Uromastyx aegyptia) create burrows that offer refuge to other species in their native desert landscapes (Williams et al., 1999); they are, however, are hunted in their hundreds for meat, as seen in (C) (Anonymous photo). Reptiles can be important predators, yet, they are widely feared (Shankar et al., 2013); (D) shows the snake-eating king cobra (Ophiophagus hanna), killed by local villagers in India (Photo: Eastern Ghats Wildlife Society). ...
Article
Full-text available
Earth's tropical ecosystems have witnessed several extinctions and a dramatic reduction of the range and abundance of large reptile species, which is directly related to the rise of early and modern humans. The occurrence of such extinctions, range reduction, species loss, and the consequences for several paramount ecosystem processes are poorly documented compared to other large vertebrate species. Here, I reviewed the literature on the ecological processes performed by large tropical reptile species and their human-induced widespread demise in order to determine knowledge gaps and encourage a paradigm shift in understanding on the interactiveness of such species. The interactions and species involved indicate that large abundant reptiles in the tropics are important in ecological processes, and can consequently have an important role in ecosystem function through gene dispersal, nutrient cycling, trophic action, and ecosystem engineering. These important interactions performed by reptiles are not solely performed by few species, or geographically restricted to islands, but instead present a pattern that repeatedly occurs in large reptiles distributed over tropical ecosystems. The observed tendency of reptiles to be tightly involved in these ecological interactions has important implications for the ecology of tropical ecosystems. Lost and current ecological processes performed by large reptiles may be orders of magnitude higher than what is currently perceived, and the misleading baseline of those processes must be addressed otherwise we risk losing species and services that are dependent of such interactions. To fix this bias I suggest: (a) Increase information spreading about Pleistocene-Holocene reptile extinctions using popular media; (b) Improved exchange between the research field of megafauna effects in ecosystems and herpetologists working with large reptiles; (c) Increase research effort on anthropogenic reptile extinctions and their potential to predict future losses; (d) Address the knowledge gaps, as human-reptile conflict, chelonian seed dispersal and nutrient movement; (e) Increase quantitative research on large reptile population ecology, density, and abundance. (f) address the potentially present or lost ecosystem effects of extant and extinct reptile species. Although the importance of reptiles in most tropical ecosystems has been perceived as negligible, this study shows that this may be a misleading paradigm.
Preprint
Full-text available
Studying animal movement provides insights into how animals react to land-use changes, specifically how animals can change their behaviour in agricultural areas. Recent reviews show a tendency for species to reduce movements in response to increased human landscape modification, but the study of movement has not been extensively explored in reptiles. We examined movements of a large reptilian predator, the King Cobra (Ophiophagus hannah), in Northeast Thailand. We used a consistent regime of radio-telemetry tracking to document movements across protected forest and adjacent agricultural areas. We then adapted GPS-targeting analytic methods to examine the movement using metrics of site reuse and dynamic Brownian Bridge Movement Model derived motion variance. Examination of motion variance demonstrated that King Cobra movements increased in forested areas and tended to decrease in agricultural areas. Our Integrated Step-Selection Functions indicated that when moving in agricultural areas King Cobras restricted their movements, thereby remaining within vegetated semi-natural areas, often located along the banks of irrigation canals. Site reuse metrics of residency time and number of revisits remained unaffected by distance to landscape features. Neither motion variance nor reuse metrics were consistently affected by the presence of threatening landscape features (e.g. roads, human settlements); suggesting that King Cobras will remain in close proximity to threats, provided habitat patches are available. Although King Cobras displayed heterogeneity in their response to agricultural landscapes, the overall trend suggested a reduction in movements when faced with fragmented habitat patches embedded in an otherwise inhospitable land-use matrix. Reductions in movements are consistent with findings for mammals and forest specialist species.
Article
Full-text available
Natural selection affects emotional and behavioural patterns, such as anti-predator adaptations, that enhance human survival. Fear is a basic emotion that activates behavioural responses upon encountering a predator, being consistently higher in females than in males. In this study, we investigated associations between fear of a large carnivore predator and perceived physical condition in a sample of Slovakian participants (n = 943). When testing evolutionary hypotheses explaining gender differences in fear of predators, we found partial support for the “physical condition” hypothesis, because females either reported lower perceived body condition than males and their perceived body condition showed significant correlation with fear of brown bear, Ursus arctos. The negative association between fear and perceived body condition was stronger in males suggesting that fear evolved as a response to higher predation pressures on males in our evolutionary past, indirectly supporting the “predation pressure” hypothesis. Males and participants with higher fear of bears wanted to exterminate bears by shooting more than others, suggesting that future management strategies should be oriented on elimination of fear of predators, as primary predictor of extremely negative attitudes toward bears.
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Full-text available
Although motorways could affect wildlife species, only few studies have been documented on their effects on mortality and isolation. With 2266 road-killed animals representing 97 species, the results of a study on a motorway section emphasized that traffic considerably affected vertebrate populations (14.5 animals day−1100 km−1). Road-killed animals were mainly mammals (43.2%), with predators also suffering critical impacts (21.7% vertebrates). Rare or endangered species such as the Midwife toad, the Blue throat, the little Horseshoe bat, or the European otter were among the victims. Animal mortality exponentially increased with traffic volume. Mortality reached almost 100% of migrants when no passage existed, and this barrier effect was only reduced when underground passages crossed the road restraining the mortality to 31% of migrants in Field mice and 23% in Common toads, while mortality always exceeded 74% in a road section with fauna ducts. It is reasonable to conclude that traffic severely influenced both wildlife species demography and population exchanges resulting in effective population isolation.
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The effects of temperature on the antipredator responses of snakes have been extensively studied during the last two decades. Several contradictory results have accumulated concerning the effects of temperature on the propensity of snakes to perform various behaviour patterns. We review this literature and discuss four possible factors related to these apparently contradictory results: (1) inconsistency in terms used to characterize antipredator behaviour; (2) erroneous citations; (3) interspecific differences; and (4) variable experimental designs. The last two factors reflect biologically important phenomena, whereas the first two are artificial "noise" that causes confusion and hinders scientific interpretation. To resolve inconsistency in wording, we propose a consistent terminology for the antipredator responses of snakes. Antipredator responses were characterized from three dimensions: (1) categorization from the viewpoint of whether prey animals move towards or away from predators (response is considered as either "approach", "neutral", or "withdrawal"); (2) categorization from the viewpoint of how much movement is involved in the behaviour (response is considered either "locomotive", "active-in-place", or "static"); and (3) categorization in terms of the apparent function (response is characterized as either "threatening", "cryptic", or "escape"). Antipredator responses of snakes, not only in relation to temperature but also in any situation, can be well characterized from these three perspectives using the proposed terminology.
Article
Recorded the antipredator responses of Thamnophis sirtalis at 10, 20, and 30°C. Several measures of antipredator behavior showed effects indicating increased passiveness and/or decreased aggressiveness with decreasing temperature. These shifts may represent an adaptive response to situations in which the snakes' movements are slowed to such an extent that aggressive striking is not an effective defense. Snakes also showed decreased aggressive defense after being touched, suggesting that initial aggressive displays were a bluff. -from Authors
Article
Intuition suggests that large, dangerously venomous snakes should be relatively invulnerable to predators, but actual data on this topic are very scarce. We examined sources of mortality in two species of large elapid snakes (eastern brownsnakes, Pseudonaja textilis, and common blacksnakes, Pseudechis porphyriacus) in the Murrumbidgee Irrigation Area in southeastern Australia. Most attacks on snakes were by people and feral cats. Over a three-year period, at least 19% of our radio-tagged brownsnakes were attacked, and eight snakes (14% of this population) were killed. We also examined road-killed snakes in the general area, and surveyed the public about where and when they encountered snakes, and how both they and the snakes responded to those situations. These questionnaire results suggest that about half of the snakes seen by people (whether in towns or on farms) were approached and about one-third were killed. Most of the mortality involved adult male snakes during the breeding season (spring). Snakes encountered by women were more likely to be killed than were those found by men. The response of snakes to encounters with people was quantified (by means of >500 encounters on regularly-walked transects) to compare with people's reports of snake responses. This comparison revealed that people are at least 20 times more likely to advance toward a snake, and 100 times more likely to attack, than is a snake to advance on, or attack, a person. People grossly over-rate the degree of aggression shown by these animals, and frequently misinterpret defensive displays as attacks. Furthermore, people are unaware of most of the snakes they encounter (especially those which use crypsis to avoid detection), and this biases the results towards over-estimation of aggressive responses. Attacks by humans on snakes are largely unjustified, and we need public education to reduce both personal risk and the slaughter of wildlife.
Article
This paper evaluates the proposition that rates of population and species extinction can be assessed by using an indirect measure: total consumption of energy (industrial plus traditional) by man. This proposition rests on three assumptions. First, the rate of extinction is proportional to the rate of habitat destruction because most organisms are adapted to rather limited environments. Second, the rate of habitat destruction is correlated with the scale of human enterprise: the product of the number of people, average consumption, and the environmental damage done by the technologies used to supply each unit of consumption. Third, average energy can be used as a surrogate for the latter two factors, consumption × technology. Total energy use is therefore an indicator of trends in extinction rates, and thus could be used to estimate the rates themselves. I examine these premises and conclude that they are sufficiently well supported for biologists to use total energy consumption as an index of global extinction rates. That index, however, is not useful politically because the assumptions upon which it is based are not understood by decision makers and the general public.
Article
Why do some species decline rapidly with anthropogenic disturbance, whereas others readily exploit disturbed habitats? It is possible that the ecological characteristics of some species render them especially vulnerable to extinction. Previous analyses of a diverse array of taxa have identified a number of intrinsic ecological predictors of vulnerability, but snakes have not been studied in this respect. We collated ecological data on Australian venomous snake species in the family Elapidae, based primarily on examination of preserved specimens in museums, to investigate possible differences between threatened and nonthreatened taxa. We also used comparative ( phylogenetically based) analyses to identify functional associations with endangerment. Correlates of conservation vulnerability identified in previous studies did not discriminate successfully between threatened and nonthreatened elapid species. However, threatened and nonthreatened elapids differed significantly in two main respects. First, threatened species tended to rely on ambush foraging rather than actively searching for prey. Sit-and-wait foragers may be vulnerable because (1) they rely on sites with specific types of ground cover, and anthropogenic activities disrupt these habitat features, and (2) ambush foraging is associated with a suite of life-history traits that involve low rates of feeding, growth, and reproduction. The second major correlate of endangerment involves the mating system. Endangered species typically lacked male-male combat: In such taxa, females grow larger than males and are more vulnerable to human predation (as judged by the composition of museum collections). Our analysis also identified taxa that, although not currently listed as threatened, share many of the ecological traits of the endangered group. Our results may facilitate future attempts to prioritize conservation actions for Australian snakes.
Article
As reptiles, snakes may have signified deadly threats in the environment of early mammals. We review findings suggesting that snakes remain special stimuli for humans. Intense snake fear is prevalent in both humans and other primates. Humans and monkeys learn snake fear more easily than fear of most other stimuli through direct or vicarious conditioning. Neither the elicitation nor the conditioning of snake fear in humans requires that snakes be consciously perceived; rather, both processes can occur with masked stimuli. Humans tend to perceive illusory correlations between snakes and aversive stimuli, and their attention is automatically captured by snakes in complex visual displays. Together, these and other findings delineate an evolved fear module in the brain. This module is selectively and automatically activated by once-threatening stimuli, is relatively encapsulated from cognition, and derives from specialized neural circuitry.
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