Patterns of resource use, overlap and partitioning among three sympatric species of south Indian pitvipers

S.R. GANESH1, S. ASOKAN1 and P. KANNAN2

1 Dept. of Zoology, Divn. of Wildlife Biology, AVC College, Mannampandal, Mayiladuthurai, Tamil Nadu, India.

2 Chennai Snake Park, Rajbhavan post, Chennai, Tamil Nadu, India.

$%675$&7  :H H[DPLQHG UHVWLQJ VXEVWUDWH XWLOL]DWLRQ KDELWDW RFFXSDQF\ DOWLWXGLQDO SUHIHUHQFH VL]HDJHFODVVGLVWULEXWLRQDQGHQFRXQWHUUDWHHVWLPDWHVRIWKUHHV\PSDWULFSLWYLSHUVSHFLHVHypnale hypnale, Trimeresurus malabaricus and Trimeresurus macrolepisLQWKH&DUGDPRP+LOOVRIWKH:HVWHUQ *KDWV 0RXQWDLQ 5DQJH VRXWKHUQ ,QGLD DQG IRXQG WKDW WKH UHVRXUFH XVH SDWWHUQ RI Trimeresurus malabaricusRYHUODSVZLWKWKDWRIHypnale hypnale and Trimeresurus macrolepis, but Hypnale hypnale and Trimeresurus macrolepis have mutually exclusive, non-overlapping resource use patterns.

ITVIPERSLQVRXWKHUQ,QGLDDUHIRXQGRQO\LQ IHZ ,QGLDQ SLWYLSHU VSHFLHV DGXOWV DQG MXYHQLOHV PKLOO\IRUHVWWUDFWV 6PLWK:KLWDNHU DUH UHSRUWHG WR XVH GLIIHUHQW UHVWLQJ VXEVWUDWHV 'DV:KLWDNHU &DSWDLQ 7KHZRUN (Whitaker & Captain, 2004). Species exhibiting DUHDRIRXUVWXG\&DUGDPRP+LOOV ž1ž( age-based microhabitat selection are considered § P $6/  LV VLWXDWHG LQ WKH :HVWHUQ DV WZR GLIIHUHQW 2FFXSDWLRQDO 7D[RQRPLF 8QLWV *KDWV0RXQWDLQ5DQJHRIVRXWKHUQ,QGLD )LJ  (Brown, 1992). Limited similarities, spatial Here the habitat type is correlated with altitude, niche segregation and character displacement are ZLWK GHFLGXRXV HYHUJUHHQ DQG PRQWDQH IRUHVW demonstrated analogous to resource-heterogeneity types occurring correspondingly in low, middle based niche partitioning (Christiansen et al., 1980). and high altitudes (Fig. 2) (Champion & Seth, *LYHQWKLVVFHQDULRWKHIROORZLQJTXHVWLRQVZHUH  )RXUVSHFLHVRISLWYLSHUVDUHUHSRUWHGKHUH raised. :KLWDNHU  &DSWDLQ   2I WKHVH Hypnale hypnale )LJ   LV D PHPEHU RI WKH Ancistrodon  'RHV UHVWLQJ VXEVWUDWH SUHIHUHQFH LQÀXHQFH complex while, Trimeresurus macrolepis (Fig. pitviper sympatry? 5), T. malabaricus (Fig. 6) and Tropidolaemus  'RHV KDELWDW W\SH DQG TXDOLW\ DIIHFW SLWYLSHU huttoniDUHPHPEHUVRIWKHTrimeresurus complex. sympatry? Tropidolaemus huttoni is very rare (David & Vogel, :LOODOWLWXGLQDOSUHIHUHQFHDOORZSLWYLSHUVWREH 1998) and was not recorded in this study. Barring V\PSDWULF",I\HVWRZKDWH[WHQW" T. huttoni, the remaining three common species :KHQPRUSKRORJ\DQGDJHFODVVSOD\VLJQL¿FDQW were investigated. Ancistrodon (sensu lato) are UROHVLQUHVWLQJVXEVWUDWHSUHIHUHQFHRISLWYLSHUV predominantly terrestrial taxa while Trimeresurus KRZ GR WKHVH YDULDEOHV DIIHFW WKHP EHLQJ (sensu lato) are both arboreal and terrestrial, and sympatric? the habit is more or less correlated to the dorsal :KDWLVWKHUHODWLYHDEXQGDQFHRIWKHVHSLWYLSHU coloration, i.e., green ones being more arboreal species? Are they equally abundant? while brown ones being more terrestrial (Whitaker,  'DYLG  9RJHO  *XPSUHFKW HW DO MATERIALS AND METHODS  7KHVHWKUHHSLWYLSHUVSHFLHVDUHIUHTXHQWO\ 6XUYH\VZHUHFRQGXFWHGIRUDSHULRGRIIRXUPRQWKV reported to be sympatric, with dynamic relationships IURP 'HFHPEHU  WR 0DUFK  9LVXDO RIFRH[LVWHQFH ,QJHUHWDO$HQJDOV Encounter Surveys (VES) were used to detect the .XPDU HW DO  .DQQDQ HW DO   ,Q D SUHVHQFHDSSDUHQW DEVHQFH RI SLWYLSHUV &UXPS

14 Number 113 - Herpetological Bulletin [2010] Resource partitioning, south Indian pitvipers

Figure 1. 0DSRIVRXWKHUQ,QGLDVKRZLQJWKH Figure 2.(YHUJUHHQ)RUHVW1DWXUDOFOLPD[ ORFDWLRQRIWKH&DUGRPRP+LOOV vegetation type.

Figure 3. Cultivated Figure 4. Hypnale hypnale tea plantation. (Merrem, 1820).

Figure 5. Trimeresurus macrolepis Figure 6. Trimeresurus malabaricus Beddome, 1862. (Jerdon, 1854).

Herpetological Bulletin [2010] - Number 113 15 Resource partitioning, south Indian pitvipers

& Scott, 1994). Possible resting substrates such FODVV 6PLWK  :KLWDNHU  &DSWDLQ   DVIDOOHQORJVURFNVEUDQFKHVEDVHRIWUHHVDQG Altitude was determined using Garmin 12 channel OHDIOLWWHUZHUHH[DPLQHG6XUYH\VZHUHFRQGXFWHG Global Positioning System. Encounter rate was in both riparian and non-riparian habitats between H[SUHVVHGDVWKHUDWLRRIVLJKWLQJIUHTXHQF\WRWKH DQGKUV7UDQVHFWVZHUHRID¿[HGOHQJWK total distance surveyed. determined using K & R pedometer (L.C. = 250 P 7KHIRUHVWSDWKWUDQVHFWVZHUHNPORQJDQG RESULTS the stream transects were 0.5 km long, as streams ,Q DOO  VLJKWLQJV RI SLWYLSHUV ZHUH UHFRUGHG in Western Ghats harbour twice as much habitat Hypnale hypnale (n = 13), Trimeresurus GLYHUVLW\ KHUSHWRIDXQDO GLYHUVLW\ DQG GHQVLW\ DV malabaricus (n = 20) and Trimeresurus macrolepis non-riparian vegetation (Ganesh et al., 2007). All Q    7KH YDOXHV REWDLQHG IRU WKH VHOHFWHG IRUHVW SDWK WUDQVHFWV ZHUH QDUURZ IRRWSDWKV QR IDFWRUV OLNH UHVWLQJ VXEVWUDWH KDELWDW W\SH greater than 1 m width, that were not necessarily altitudinal range, size/age class and encounter rate in a straight line. Stream transects were small river estimates are shown in Table 1. courses, with maximum stream width no greater WKDQP7KHYHJHWDWLRQW\SHFODVVL¿FDWLRQIROORZV Resting Substrate &KDPSLRQ 6HWK  7KHWRWDOOHQJWKRIWKH Fallen logs were mostly used by H. hypnale VPDOOHVW IHPDOH ZDV XVHG WR GHWHUPLQH VL]HDJH (38.4%), rocks were mostly used by T. malabaricus

H. hypnale (n = 13) T. malabaricus (n = 20) T. macrolepis (n = 16) Factors Variables

Resting Fallen log 5*# (38.4%) 2* (10%) 0 Substrate Rock 2* (15.3%) 11*# (55%) 0 Branch 0 5* (25%) 16*# (100%) Tree base 2* (15.3%) 1* (5%) 0  /HDIOLWWHU           Bare ground 2 (15.3%) 0 0

Habitat Deciduous 6*# (46%) 3* (15%) 0 Type Evergreen 4* (30.7%) 13*# (65%) 0 Montane 0 0 7# (43.7%) Tea 0 0 2 (12.5%)  &RIIHH              Cardamom 0 1* (5%) 5* (31.2%)

Altitude 500-800 12*# (92.3%) 3* (15%) 0 (m) 800-1000 1* (7.7%) 13*# (65%) 0 1000-1300 0 4* (20%) 4* (25%) 1300-1600 0 0 12# (75%)

6L]H$JH6XEDGXOWV         &ODVV $GXOWV         Ratio 31:69% 35:65% 37:63%

Encounter Paths 10/17=0.58# 6/26=0.23 13/20=0.65# Rate Est. Streams 3/8=0.38 14/13=1.07# 3/10=0.30 (km) Overall enc. rate 13/25=0.52 20/39=0.51 16/30=0.53

Table 1. 9DOXHVRI YDULRXV VHOHFWHG IDFWRUV DQG YDULDEOHV IRU WKUHH VSHFLHV RI SLWYLSHUV 1XPEHUV GHQRWH VLJKWLQJ IUHTXHQF\ GHQRWHVRYHUODSGHQRWHVPD[LPXPYDOXH

16 Number 113 - Herpetological Bulletin [2010] Resource partitioning, south Indian pitvipers

(55%) and T. macrolepis exclusively used branches two km will yield one pitviper sighting, regardless (100%). Overlap was observed in the resting RI VSHFLHV KDELWDW HOHYDWLRQ DQG VL]HDJH FODVV VXEVWUDWH XVDJH RI T. malabaricus with both H. in this season, in this hill range. The species will hypnale and T. macrolepis. But H. hypnale and T. depend on the habitat and altitude. macrolepis had mutually exclusive resting substrate SUHIHUHQFHV DISCUSSION H. hypnaleLVSUHGRPLQDQWO\WHUUHVWULDODVLQIHUUHG Habitat Type E\RXUVWXG\DQGOLWHUDWXUHUHFRUGV 6PLWK 6LJKWLQJ IUHTXHQFLHV RI SLWYLSHUV ZHUH JUHDWHU LQ Whitaker & Captain, 2004). Smith (1943) reported SULVWLQHIRUHVWV  WKDQLQHVWDWHV   H. hypnale resting on shrubs but we did not UHJDUGOHVVRIWKHVSHFLHVRUWKHKDELWDW'HFLGXRXV observe this behaviour. We recorded T. macrolepis DQGHYHUJUHHQIRUHVWVZHUHRFFXSLHGE\H. hypnale RQO\RQEUDQFKHVRIWUHHVDQGVKUXEV7KLVVSHFLHV and T. malabaricus 0RQWDQH IRUHVWV DQG WHD LVUHJDUGHGDVDUERUHDODQGWHUUHVWULDO 6PLWK estates were occupied only by T. macrolepis (Figs. 0DOKRWUD  'DYLV  :KLWDNHU  &DSWDLQ 2 and 3). Cardamom estates were occupied by T.  0RUHRYHUWKRVHVSHFLHVRISLWYLSHUVWKDWDUH malabaricus and T. macrolepis&RIIHHHVWDWHZDV primarily green in colour are said to be arboreal, the only habitat occupied by all three species. while the many-coloured species like the Malabar Rock Pitviper (T. malabaricus) are said to be Altitude WHUUHVWULDOIRUPV :KLWDNHU T. malabaricus Overlap was observed between H. hypnale and ZDV PRUH IUHTXHQWO\ VLJKWHG LQ ULSDULDQ KDELWDWV T. malabaricus in 500-1000 m and between T. DV LQIHUUHG E\ RXU VWXG\ 7KH IUHTXHQW DUERUHDO malabaricus and T. macrolepis in 1000-1300 m. WHQGHQFLHV RI MXYHQLOH T. malabaricus has been But there was no overlap between H. hypnale and ZLGHO\ UHSRUWHG 6PLWK  :KLWDNHU  T. macrolepis([FOXVLYHVLJKWLQJVRIT. macrolepis &DSWDLQ 2XUREVHUYDWLRQRIDOOVL[MXYHQLOHV ZHUH IURP -1600 m. The altitudinal range and sub-adults on shrubs is strongly supportive to where T. malabaricus was recorded (500-1300 m) literature. also harboured the other two species. We sighted H. hypnaleLQGHFLGXRXVIRUHVWVT. malabaricusLQHYHUJUHHQIRUHVWVDQGT. macrolepis Size/Age class LQPRQWDQHIRUHVWVWKHPRVW:KLWDNHU  DQG Juveniles were scarcer (31-37%) than adults (63- .XPDUHWDO  VWDWHGWKDWPRQWDQHIRUHVWVZHUH 67%), among all three pitviper species. The least SUHIHUUHG E\ T. macrolepis. Aengals (1995) and IUHTXHQF\RIVXEDGXOWV LHWKHKLJKHVWIUHTXHQF\ Malhotra & Davis (1991) recorded T. malabaricus RI DGXOWV  ZDV UHFRUGHG LQ H. hypnale IROORZHG and T. macrolepis IURP9DOSDUDLDQG6ULYLOOLSXWKXU by T. malabaricus and T. macrolepis7KHUDWLRRI hills respectively, which are primarily montane VLJKWLQJ IUHTXHQFLHV RI VXEDGXOWV DGXOWV UDQJHG IRUHVWKDELWDWVZKLOH,QJHUHWDO  UHFRUGHG IURP-37:63-69%. H. hypnale and T. malabaricusIURP3RQPXGLDQ HYHUJUHHQIRUHVWKDELWDWDQGIRXQGERWKVSHFLHVWR Encounter Rate Estimates be more abundant in this habitat than deciduous $OO WKH VSHFLHV ZHUH XQLIRUPO\ VDPSOHG ZLWK belts. Kumar et al. (2001) recorded all three species SURSRUWLRQDWHO\HTXDOQXPEHURIULSDULDQDQGQRQ IURP $QDLPDODL KLOOV ZKLFK KDV ERWK HYHUJUHHQ riparian transects surveyed. Total distance walked DQGPRQWDQHIRUHVWV ZDVFRPSDUDEOHZLWKUHVSHFWWRWKHQXPEHURIGD\V Whitaker & Captain (2004) mention the VXUYH\HGIRUDOOWKUHHVSHFLHV1XPEHURIWUDQVHFWV DOWLWXGLQDOUDQJHRIH. hypnale to be 300-600 m. In ZDONHGIRUHDFKVSHFLHVGLIIHUHGGXHWRLQHYLWDEOH WKHSUHVHQWVWXG\RQHLQGLYLGXDORIH. hypnale was natural constraints like correlation between habitat seen above 800 m. Thus there are good chances type and altitudinal range. Encounter rates were IRU LW WR RFFXU V\PSDWULFO\ ZLWK RWKHU KLJKHU DOVRFRPSDUDEOHIRUDOOWKHWKUHHVSHFLHV  elevation species. Whitaker & Captain (2004) DQGUHVSHFWLYHO\ 7KXVDGLVWDQFHFRYHUDJHRI states that, both T. macrolepis and T. malabaricus

Herpetological Bulletin [2010] - Number 113 17 Resource partitioning, south Indian pitvipers

RFFXUIURPP%XWLQWKHSUHVHQWVWXG\ a marginal overlap. It was also observed that there no T. macrolepis was recorded below 1000 m and was an altitudinal separation in their distribution, no T. malabaricus was sighted above 1300 m. It is with a marginal overlap. It is clear that all three noteworthy to mention here that this survey was VSHFLHVRISLWYLSHUVDUHHTXDOO\DEXQGDQWDVLQIHUUHG XQGHUWDNHQIURP-1600 m, in hills covered with IURP WKHLU HQFRXQWHU UDWHV 7KXV WKHRUHWLFDOO\ all the three habitat types inhabited by pitvipers. WKHVH WKUHH SLWYLSHU VSHFLHV ZLWK GLIIHUHQW UHVWLQJ In general, literature states that, higher elevation VXEVWUDWH SUHIHUHQFHV FDQ EH V\PSDWULF DOWKRXJK IRUHVWV !  P  ZHUH RIWHQ UHFRUGHG WR KDYH DOWLWXGH LV D OLPLWLQJ IDFWRU 7KH\ ZHUH LQGHHG either or both T. macrolepis, T. malabaricus V\PSDWULFLQDZLGHUDOWLWXGLQDOUDQJHRI-1300 $HQJDOV  .XPDU HW DO  0DOKRWUD  PWKHWUDQVLWLRQ]RQHRIGHFLGXRXV- evergreen - 'DYLV DQGORZHUHOHYDWLRQIRUHVWV  PRQWDQHIRUHVWW\SHVZKHUHT. macrolepis was not m) were reported to have either or both, H. hypnale, dominant. The other two species were observed to T. malabaricus ,QJHUHWDO.DQQDQHWDO be dominant in this altitudinal range. The sighting 2006). However, in one instance H. hypnale, T. IUHTXHQFLHVRIWKHWKUHHVSHFLHVZHUHUHODWLYHO\ORZ macrolepis and T. malabaricus all coexisting in in intermediary altitudinal zones where they were WKHVDPHIRUHVWKDVEHHQUHFRUGHGIURP$QGLSDUDL sympatric. (1000 m), in Anaimalai hills (Kumar et al., 2001). 2QH VSHFLHV GLIIHUHG IURP WKH RWKHU WZR LQ In the present study however, we did not observe WHUPV RI QLFKH EUHDGWK T. malabaricus is (1) DOOWKHWKUHHVSHFLHVWREHV\QWRSLF7KLVFRQIXVLQJ both arboreal and terrestrial (vs. predominantly VWDWH UHJDUGLQJ DOWLWXGLQDO GLVWULEXWLRQ RI VRXWK terrestrial H. hypnale and predominantly arboreal ,QGLDQSLWYLSHUVQHFHVVLWDWHVIXUWKHU¿HOGVWXGLHV T. macrolepis   KDVSUHIHUHQFHIRUPLGDOWLWXGH :H REVHUYHG IHZHU MXYHQLOHV -37%) ]RQHV YV SUHGRPLQDQWO\ ORZ DOWLWXGH SUHIHUULQJ than adults (63-67%) revealing an equal and H. hypnale and predominantly high altitude KRPRJHQRXVUHFUXLWPHQWRISRSXODWLRQV7KXVRXU SUHIHUULQJ T. macrolepis) and (3) is primarily a GDWD FRUURERUDWHV SUHYLRXV ¿QGLQJV WKDW VXJJHVW riparian habitat species (vs. primarily non-riparian WKH UHVXOW RI KLJK PRUWDOLW\ LQ MXYHQLOHV DQG KDELWDWSUHIHUULQJH. hypnale and T. macrolepis). LQFUHDVHGOLIHH[SHFWDQF\ZLWKDJHLVWKDWWKHDGXOW 7KHUHIRUHT. malabaricusKDVGLYHUJHGSUHIHUHQFHV SRSXODWLRQVRIVQDNHVUHSUHVHQWWKHDFFXPXODWLRQ thus avoiding resource-competition with H. hypnale RIPDQ\\HDUV¶UHSURGXFWLRQ 3RUWHU  and T. macrolepis. H. hypnale and T. macrolepis, Our study produced equal encounter rate GHVSLWHEHLQJFDSDEOHRIRFFXUULQJV\PSDWULFO\ZLWK estimates and hence equal relative abundance (0.51- one another (due to their mutually exclusive resting 0.53 sightings per km) equating to one sighting VXEVWUDWH SUHIHUHQFHV  ZHUH REVHUYHG VHSDUDWHO\ per 2 km. The relatively lower encounter rates in EHFDXVH RI WKHLU GLYHUVH DOWLWXGLQDO SUHIHUHQFHV anthropogenic (5-31.2%) than pristine habitats 7KLV ZDV DQ DGYDQWDJH IRU WKH PLGHOHYDWLRQ (15-65%) is in accordance with Porter (1972) SUHIHUULQJ T. malabaricus. Thus the resource use who remarked that snake populations seem to be SDWWHUQRIT. malabaricusRYHUODSVZLWKWKDWRIWKH UHJXODWHGE\FRQGLWLRQVRIFRYHUIRRGDQGEDVNLQJ other two species, which in turn have mutually VLWHV7KHKLJKRSWLPDOFRQGLWLRQVIRXQGLQSULVWLQH exclusive, non-overlapping resource use patterns. conditions support higher densities and diversities This is a preliminary study and a more detailed, RI VQDNHV WKDQ OHVV IDYRXUDEOH FRQGLWLRQV DV ORQJWHUPVWXG\LQYROYLQJDJUHDWHUVDPSOHVL]HRI anthropogenic pressures will degrade its abiotic each pitviper species and increased geographical and thus its biotic content. UDQJHLVQHHGHGIRUDEHWWHUXQGHUVWDQGLQJRIWKHLU ecology. CONCLUSION ,WLVZHOOXQGHUVWRRGWKDWRIWKHWKUHHVSHFLHVRI ACKNOWLEDGEMENTS pitvipers studied, one is terrestrial, another is We thank Tamil Nadu Forest Department, arboreal and the other both terrestrial and arboreal. Sukhdev, P.C.C.F, Srinivasa Reddy, D.F.O. Theni, 7KXVWKH\GLIIHUHGLQUHVWLQJVXEVWUDWHXVDJHZLWK 6XEUDPDQLDP')29LUXGXQDJDUIRUSHUPLVVLRQ

18 Number 113 - Herpetological Bulletin [2010] Resource partitioning, south Indian pitvipers

0 9DUGDUDMDQ WKH WKHQ +HDG RI WKH ,QVWLWXWLRQ Ganesh, S.R., Chandramouli, S.R. & Edward, S.L. $9&&ROOHJH9.DODLDUDVDQDQG55DMDUDWLQDP  $VWXG\RQ+HUSHWRIDXQDODVVHPEODJHV RI &KHQQDL 6QDNH 3DUN 76 6XEUDPDQLDP LQWKHUDLQIRUHVWVRI:HVWHUQ*KDWV.DUQQDWDND Raja, Shyam Raja, Anand Raja, Raghu Raja, India. J. Sci. Trans. Environ. Technov. 1 (2), 5DPNXPDUDQG5DMNXPDURI:LOGOLIH$VVRFLDWLRQ 95-103. RI5DMDSDOD\DP :$5 IRUIXQGLQJKHUSHWRORJLVWV Gumprecht, A., Tillack, F., Orlov, N.L., Captain, 5RPXOXV :KLWDNHU DQG *HUU\ 0DUWLQ IRU WKHLU A. & Ryabov, S. (2004). Asian Pitvipers. Berlin: VXJJHVWLRQV 5XFKLUD 6RPDZHHUD 5RZODQG Geitje Books. 368 pp. *ULI¿Q DQG DQ DQRQ\PRXV UHIHUHH IRU WKHLU OXFLG ,QJHU5)6KDIIHU+%.RVK\0 %DNGH5 FRPPHQWVZKLFKLPSURYHGWKLVPDQXVFULSWHVWDWH  $UHSRUWRQDFROOHFWLRQRI$PSKLELDQV managers, Prabhu Datta, Krishnan Nair, Chandran DQG 5HSWLOHV IURP WKH 3RQPXGL .HUDOD VRXWK DQG5DMNXPDUIRUKRVSLWDOLW\DQGZRUNSHUPLVVLRQ India. J. Bombay Nat. Hist. Soc. 81 (2), 406- ZLWKLQWKHHVWDWHVDQGWKHHVWDWHZRUNHUVIRUWKHLU 570. unmatched company. Kannan, P., Rajaratinam, R. & Kalaiarasan, V.  +XVEDQGU\RIVRPHSLWYLSHUVDW&KHQQDL REFERENCES Snake Park. Cobra 63, 1-3. $HQJDOV 5   5HSWLOLDQ IDXQD LQ WKH Kumar, A., Chellam, R., Chowdry, B.C., Mudappa, SODQWDWLRQV RI 9DOSDUDL :HVWHUQ *KDWV 7DPLO D., Vasudevan, K., Ishwar, N.M. & Noon, B. Nadu. Cobra 5, 7-12.   ,PSDFW RI UDLQIRUHVW IUDJPHQWDWLRQ RQ %URZQ6  0LFURKDELWDWUHODWLRQVRIVRPH VPDOOPDPPDOVDQGKHUSHWRIDXQDLQWKH:HVWHUQ snakes and lizards in Tamil Nadu, south India. *KDWV VRXWK ,QGLD $ VXPPDU\ RI UHVHDUFK Hamdryad 17, 35-38. ¿QGLQJV 5HSRUW VXEPLWWHG WR 86 )LVK DQG Champion, H.G. & Seth, S.K. (1968). A Revised :LOGOLIHVHUYLFH:LOGOLIH,QVWLWXWHRI,QGLDDQG Survey of the Forest Types in India. New Delhi, 6DOLP$OL &HQWUH IRU 2UQLWKRORJ\ DQG 1DWXUDO ,QGLD0DQDJHURI3XEOLFDWLRQVSS History, India, 28 pp. Christianson, B., Freddy, I. & Loesche, V. (1980). Malhotra, A. & Davis, K. (1991). A report on the (YROXWLRQ  ,QWUDVSHFLILF H[SORLWDWLYH KHUSHWRORJLFDO VXUYH\ RI WKH 6ULYLOOLSXWKXU FRPSHWLWLRQ  RQH ORFXV WKHRU\ IRU VPDOO Reserve Forests, Tamil Nadu. J. Bombay Nat. DGDSWLYH JHQH HIIHFWV Theor. Pop. Biol. 18, 3, Hist. Soc. 88 (2), 157-166. 297-313. Porter, R.H. (1972). Herpetology. U.S.A.: W.B. Crump, M.L. & Scott, N.J. (1994). Visual Encounter Sanders Company. 524 pp. Survey. In: Measuring and Monitoring Biological Smith, M.A. (1943). Fauna of British India, Diversity: Standard Methods for Amphibians. Including Ceylon and Burma. Vol. III Serpentes. W.R. Heyer, M.A. Donnelly, R.W. McDiarmid, London: Taylor & Francis Publications. 583 pp. L.C. Hayek & M.S.Foster (Eds.). Pp. 84-96. Whitaker, R. (1973). Pitviper (Trimeresurus Washington: Smithsonian Institution Press. macrolepis) bites in a south Indian tea estate. J. Das, I. (2002). A Photographic Guide to Snakes Bombay Nat. Hist. Soc. 70 (1), 207. and Other Reptiles of India. United Kingdom: Whitaker, R. (1978). Common Indian Snakes - A New Holland Publications. 144 pp. Field Guide. New Delhi, India: Macmillan 'DYLG 3  9RJHO *   5HGHVFULSWLRQ RI press. 154 pp. Trimeresurus huttoni, Smith, 1949 (Serpentes, Whitaker, R. & Captain, A. (2004). Snakes of India &URWDOLQDH ZLWKDGLVFXVVLRQRILWVUHODWLRQVKLSV - The Field Guide. Chengelpat, Tamil Nadu, Hamadryad 22 (2), 73-87. India: Draco Books. 481 pp.

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