Factors influencing the occurrence of negative interactions between people and crocodilians in Mexico
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Factors influencing the occurrence of negative
interactions between people and crocodilians
in Mexico
GIOVANY ARTURO GONZÁLEZ-DESALES, LUIS SIGLER, JESÚS GARCÍA-GRAJALES
PIERRE CHARRUAU, MARTHA MARIELA ZARCO-GONZÁLEZ
Á N G E L B A L B U E N A - S E R R A N O and O C T A V I O M O N R O Y - V I L C H I S
Abstract Negative interactions between people and croco- Introduction
dilians have increased worldwide, but in Mexico there
f the species of crocodilians (Uetz et al., ),
have been few systematic reports and no rigorous evaluation
of this problem. We compiled information on negative O one species of the family Alligatoridae, the spectacled
caiman Caiman crocodilus, and two species of the family
interactions between people and the spectacled caiman
Caiman crocodilus and American crocodile Crocodylus Crocodylidae, the American crocodile Crocodylus acutus
acutus from the Worldwide Crocodilian Attack Database and Morelet’s crocodile Crocodylus moreletii occur in Mex-
for –, and we investigated interactions in greater ico. On the IUCN Red List C. crocodilus and C. moreletii
depth, through interviews with people in La Encrucijada are categorized as Least Concern and C. acutus as Vulnerable
Biosphere Reserve. We examined the relationship between (Cedeño-Vázquez et al., ; Ponce-Campos et al., ;
the occurrence of negative interactions between people Balaguera-Reina & Velasco, ), and in Mexico the three
and C. acutus and the species’ nesting season and abun- species are subject to Special Protection (SEMARNAT,
dance, and presence records. In Mexico, the frequency of ). Populations of C. acutus and C. crocodilus were
negative interactions increases when anthropogenic activ- severely affected by hunting for their skins until this was
ities occur close to nesting sites (, km) and during the permanently banned in the s. Since then the populations
nesting season (February–September). In La Encrucijada, of the three species have increased, although in some regions
following negative interactions with crocodiles, the local of Mexico they are still exploited (INE-SEMARNAP, ;
inhabitants killed crocodiles measuring . . m long in Aguilar-Galindo, ).
–. The frequency of negative human–crocodilian As a result of this recovery of crocodilian populations,
interactions was not correlated with the abundance of cro- and because of land-use change, flooding, human popu-
codilians but was correlated with the number of presence re- lation growth and feeding of crocodiles by people, negative
cords of crocodiles. Strategies to minimize these interactions interactions between people and crocodiles have escalated
include warnings at nesting sites, increased monitoring of (García-Grajales, ). Crocodile behaviour, such as terri-
anthropogenic activities during the nesting season, and torial and self defence, and nest protection by females,
management of nests to prevent them being destroyed by exacerbate these negative interactions (Pooley et al., ;
people. García-Grajales & Buenrostro-Silva, ). In the Americas,
C. acutus and C. moreletii have been involved in a number
Keywords Caiman crocodilus, crocodile, Crocodylus acutus, of fatal incidents, with . and . cases/year, respectively
human activities, human–crocodile conflict, Mexico, (Sideleau, ). Such incidents are not, however, always
nesting, relative abundance recorded (Aust et al., ). Systematic compilation of
data on interactions between people and crocodilians is re-
quired to identify the potential risks to people from croco-
diles, and to avoid retaliatory killings (Caldicott et al., ).
GIOVANY ARTURO GONZÁLEZ-DESALES, MARTHA MARIELA ZARCO-GONZÁLEZ, ÁNGEL In the state of Chiapas in Mexico negative interactions
BALBUENA-SERRANO and OCTAVIO MONROY-VILCHIS (Corresponding author)
Centro de Investigación en Ciencias Biológicas Aplicadas, Universidad between crocodiles and people could be expected, as all
Autónoma del Estado de México, Instituto Literario 100, Col. Centro, C.P. three species occur there, but in the Worldwide Crocodilian
50000 Toluca, Estado de México, Mexico Attack Database (CrocBITE, ) only four incidents have
E-mail tavomonroyvilchis@gmail.com
been recorded in this state, which is probably an under-
LUIS SIGLER The Dallas World Aquarium, Dallas, USA
estimate. Here we examine the following questions: () Does
JESÚS GARCÍA-GRAJALES Universidad del Mar Campus Puerto Escondido, San
Pedro Mixtepec, Oaxaca, Mexico
the frequency of negative human–crocodilian interactions
increase during the nesting season? () Does the frequency
PIERRE CHARRUAU Centro del Cambio Global y la Sustentabilidad A.C. Calle
Centenario del Instituto Juárez s/n, Villahermosa, Tabasco, Mexico of incidents increase when there is human habitation within
Received August . Revision requested October .
nesting areas? () Does the frequency of such interactions
Accepted June . First published online May . increase with crocodile abundance, both nationally in
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use,
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https://doi.org/10.1017/S0030605319000668
Oryx, 2021, 55(5), 791–799 © The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605319000668
792 G. A. González‐Desales et al.
TABLE 1 Records of the relative abundance index of Crocodylus acutus in Mexico during –, from various sources, and in .
Relative
abundance
Locality, State Year index1 Source
Amela lagoon, Colima (not indicated) 45 Castillo (1996)
Chamela-Cuixmala Biosphere Reserve, Jalisco 1987–2003 20.57 García et al. (2010)
Chiricahueto lagoon, Sinaloa 1996 6.94 León-Ojeda et al. (1997)
La Encrucijada, Biosphere Reserve, Chiapas 1996 2.1 (11.5) Martínez-Ibarra et al. (1997)
El Verde estuary, Sinaloa 1999–2000 7.7 Navarro-Serment (2001)
Boca Negra estuary, Jalisco 1999–2002 45.4 (0.7) Huerta (2005)
La Manzanilla estuary, Jalisco 1999–2002 40.9 (2.3) Huerta (2005)
La Ventanilla estuary, Oaxaca 2000–2001 47.3 (9.7) Espinosa-Reyes & García-Grajales (2001)
Majahuas estuary, Jalisco 2000–2002 5.2 (4.6) Huerta (2005)
Boca Negra estuary, Jalisco 2001 18.25 (0.8) Cupul-Magaña et al. (2002)
Sumidero Canyon National Park, Chiapas 2001 2.8 (15) Sigler (2010)
Banco Chinchorro Biosphere Reserve, Quintana Roo 2003 6.8 Charruau et al. (2005)
La Palmita lagoon, Oaxaca 2004–2005 6.38 (4.9) Brandon-Pliego (2007)
San Blas estuary, Nayarit 2005–2007 1.94 (14.8) Hernández-Hurtado et al. (2011)
El Cajon reservoir, Nayarit 2010–2011 0.67 (15.2) González (2013)
Majahuas estuary, Jalisco 2010–2015 10.46 Tello (2016)
San Juan lagoon, Jalisco 2010–2015 8.75 Tello (2016)
Palmasola lagoon, Oaxaca 2012 70.1 (0.6) García-Grajales & Buenrostro-Silva (2014)
La Encrucijada, Biosphere Reserve, Chiapas 2014 1.5 (28) This study
Surveyed km, where known, are given in parentheses.
Mexico and locally in El Hueyate estuary in Chiapas? In of Mexican municipalities (INEGI, ) with records of
addition, we examine the relationship of the number of negative interactions and the presence of crocodiles: ()
negative incidents and presence records of C. acutus with principal economic activity (as primary: agriculture, live-
socio-economic variables. stock, forestry, hunting, fishing; secondary: mining, oil and
gas extraction, manufacturing, electricity, water supply,
Methods construction; services: transport, government, other), ()
education level of males (mean years of study), () human
Negative interactions with C. acutus in Mexico population density (inhabitants/km), () number of males
in the population, () number of economically active males,
Monthly records of negative interactions with C. acutus and () municipality area (ha). We focused only on the
in Mexico, with geographical coordinates, were compiled characteristics of the male population, as negative inter-
from CrocBITE () for August – June . actions occur most frequently with them (García-Grajales
From the coordinates we calculated the Euclidean distances & Buenrostro-Silva, ).
to the nearest nesting site (Casas-Andreu, ; Cedillo-Leal
et al., ; Cupul-Magaña et al., ; Valtierra-Azotla, Human–crocodilian interactions in El Hueyate estuary
; Charruau et al., ; Sigler, ; Charruau et al.,
; Hernández-Hurtado et al., ; González-Desales El Hueyate estuary in the La Encrucijada Biosphere Reserve
et al., a; Charruau et al., ) and to the nearest site on the Pacific coast of Chiapas state (Fig. ) has two core
for which relative abundance data were available (Table ), areas (, ha: El Palmarcito and La Encrucijada), and a
using ArcGis . (Esri, Redlands, USA). The distance of in- , ha buffer zone (INE-SEMARNAP, ). Within
teractions to nesting sites and the distance of interactions to the Reserve the caiman subspecies C. crocodilus chiapasius
sites where abundance of C. acutus had been evaluated were and C. acutus occur in both natural and anthropogenic
classified in intervals, based on the Rule of Sturges (Sturges, ecosystems (dams, cattle ponds, fishery ponds and pampas;
). Using simple linear regression, we examined the rela- Sigler, ). There are human settlements and ,
tionships between interaction frequency and proximity to inhabitants in the Reserve, of which .% do not receive
nesting sites, relative abundance of crocodiles, and number school education of any level; the main economic activi-
of presence records of C. acutus up to June , (the ties are fishing, agriculture and livestock breeding (INE-
latter from GBIF, ). A χ test was used to identify any SEMARNAP, ). Reports indicate there are more
association between interactions and the nesting season of crocodilians in the core zone than elsewhere (Sigler &
C. acutus. We describe six socio-economic characteristics Martínez-Ibarra, ; Peña, ) and nesting of both
Oryx, 2021, 55(5), 791–799 © The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605319000668
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https://doi.org/10.1017/S0030605319000668Human–crocodilian interactions 793
LED white light to search for the brightness of crocodilian
eyes by projecting the light beam between the boat and the
mangroves (Chabreck, ). When we located eye-shine we
decreased speed and slowly headed towards the individual,
to identify it (differentiation of the species was by the pres-
ence of bony crests and ossified inter-orbital bridge in the
case of C. crocodilus, and the absence of these characteristics
in C. acutus). The km of the El Hueyate estuary monitored
were the same stretch of the estuary surveyed in earlier stud-
ies (Martínez-Ibarra et al., ; Sigler & Martínez-Ibarra,
; Peña, ).
Results
FIG. 1 La Encrucijada Biosphere Reserve, with the locations Negative interactions with C. acutus in Mexico
of the six negative interactions (cases) between people and
crocodilians recorded during – (Table ), five with CrocBITE () contains records of negative interac-
American crocodiles Crocodylus acutus and one (Case ) with tions between people and C. acutus in Mexico during
a spectacled caiman Caiman crocodilus chiapasius, and nests August – June , and no reports of interactions
recorded in . For details of the six cases, see Table . with C. crocodilus chiapasius. Of the records only in-
cluded geographical location. There was a significant nega-
species has been recorded (Sigler & Martínez-Ibarra, ; tive relationship between the frequency of interactions and
González-Desales et al., a,b), and therefore we examined distance to the nearest nesting site (r = –.; P , .); i.e.
human–crocodilian interactions and abundance of crocodi- there were more interactions closer to nesting sites. There
lians only in the core zone. was also a significant relationship between the number
During October –September we conducted of negative interactions and presence records of C. acutus
unstructured interviews in the principal settlements on the (r = .; P , .). There was no significant relationship
margin of the El Hueyate estuary (Aztlán, Brisas del Hueyate between the frequency of negative interactions and the
and La Ceiba) with people (five women and men; – relative abundance of C. acutus (r = –., P . .). With
years old), who were either involved in incidents, or relatives respect to the date of incidents, there were significantly
of those involved. As the total population in these settle- more negative interactions during the nesting season than
ments is , (CONABIO, ), we interviewed % of the at other times (χ = ., df = , P , .; Fig. ). Regard-
total population. We focused on obtaining information ing the socio-economic characteristics of the municipal-
about the date and location of any interactions, any actions ities where there were negative interactions or presence
taken against the crocodilians, activities that people were records, the economic activity ‘services’ was the most com-
performing at the time of the incidents, and information mon in municipalities where interactions ( munici-
from people that witnessed the events. From onwards palities) and sightings occurred ( municipalities), human
we have made – visits per year to monitor reports of any population density was lower in municipalities with nega-
additional negative interactions. We have knowledge of an tive interactions (mean . ± SD . inhabitants/km), and
incident that occurred in March but we have not yet in municipalities with negative interactions .% of the
been able to interview the family members of the affected adult male population (– years old) had a mean of
person. . ± SD . years of education.
The abundance of C. acutus and C. crocodilus chiapasius
was analysed using the Relative Abundance Index Rsp/ Human–crocodilian interactions in El Hueyate estuary
travelled distance, where Rsp is the number of records
of each species and travelled distance is the total number We obtained data on the relative abundance of C. acutus in
of km travelled during monitoring (Sigler et al., ). We El Hueyate estuary for , , and –, with
obtained relative abundance data of both crocodilians .–. individuals per km, and for C. crocodilus chiapasius
from literature (Martínez-Ibarra et al., ; Sigler & for and –, with –. individuals per km
Martínez-Ibarra, ; Peña, ) and our fieldwork in (Fig. a). The relative abundance index calculated for our
. In El Hueyate estuary we conducted surveys during fieldwork in was . C. acutus per km and . C.
March–October during the nesting season of C. acutus crocodilus chiapasius per km.
and C. crocodilus chiapasius. The surveys were performed We obtained information on six negative interactions
from a m boat with a HP outboard motor, using a between people and crocodilians in El Hueyate estuary
Oryx, 2021, 55(5), 791–799 © The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605319000668
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https://doi.org/10.1017/S0030605319000668794 G. A. González‐Desales et al.
FIG. 2 Negative interactions by month involving C. acutus in
Mexico, showing that the incidents are more frequent in nesting
season.
during – (Fig. b). Two of the incidents were fatal,
two resulted in major injury (limb loss or permanent motor
impairment) and two resulted in minor injury. Five of the
incidents involved C. acutus and one C. crocodilus chiapa-
sius (Table ).
According to the interviewees, incidents between croco-
diles and domestic animals (mainly dogs) and livestock
(cattle and pigs) are common in the area. Following nega-
tive interactions with crocodiles, adult crocodiles were
hunted by the inhabitants of the three settlements during
–. Five of the six negative interactions recorded
occurred close to nesting sites (Table ), where we observed FIG. 3 (a) Relative abundance index (crocodilians observed
nests of C. acutus and of C. crocodilus chiapasius in per km, during –) of C. acutus and C. crocodilus
(Fig. ; González-Desales et al., a,b). chiapasius, and (b) the number of negative human–crocodilian
interactions per year (during –), in El Hueyate estuary,
La Encrucijada Biosphere Reserve, Mexico.
Discussion
As far as we are aware, this study is the first analysis of the However, with illegal killings as high as individual croco-
potential causes of the negative interactions between people diles per incident (according to the people we interviewed),
and C. acutus in Mexico, and the first standardized report of such killings would be expected to affect abundance,
populations trends of C. crocodilus chiapasius and C. acutus especially if any of the crocodiles killed are reproductive
in a coastal region of Chiapas. For Crocodylus porosus, in females. A similar situation occurs in other regions of
Australia and Sri Lanka, abundance and protection of the Mexico. Hernández-Hurtado et al. () reported
nest by females are the main factors that increase the prob- negative incidents during – in the Western Pa-
ability of negative interactions with people (Caldicott et al., cific region, following which crocodiles were hunted,
; Amarasinghe et al., ). Our study suggests, how- injured or captured, of which were hunted in Manzanilla,
ever, that the abundance of C. acutus does not influence Jalisco. The illegal killing of crocodiles has been reported
the frequency of incidents in Mexico. elsewhere after negative interactions, such as with C. porosus
The survey method used for the calculation of the relative in Sri Lanka (Amarasinghe et al., ).
abundance index is potentially subject to biases (García- Following negative interactions between C. acutus
Grajales et al., ) and therefore the lower relative and people in La Encrucijada, there was an apparent
abundance we detected in La Encrucijada in cannot decrease in abundance of the species, to a level similar to
necessarily be attributed to the illegal killing of crocodiles. that recorded when protection of the species began in this
Oryx, 2021, 55(5), 791–799 © The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605319000668
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Oryx, 2021, 55(5), 791–799 © The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605319000668
TABLE 2 Incidents of negative interactions with crocodilians during – in El Hueyate estuary and nearby areas. Case five was with a spectacled caiman Caiman crocodilus chiapasius
and the other cases were with American crocodiles Crocodylus acutus.
Distance Consequences of Length of
Age incident–nest Actions following incident for the crocodilian Actions against
Case Month & year (years) Occupation Activity (km) incident affected person (m) crocodilians
1 2005 42 Fisher Unknown 0.03 Search by local Fatal Unknown None
authorities & relatives
located clothing & it
was concluded he was
killed by crocodiles
2 April 2011 21 Student, fisher Swimming in 1.72 Medical & psychological Non-fatal, loss of 3.7 Killing crocodiles until
the estuary attention right arm missing arm located
3 February 2011 35 Fisher Preparing a bird 0.01 Medical attention Non-fatal, scars on 2.5 None
on the estuary abdomen
bank
4 2011 32 Fisher Fishing at the 1.93 Medical attention Non-fatal, lesions on 2.5 Killing crocodiles
estuary shore the foot & difficulty $ 2.5 m long
with walking
5 May 2012 44 Fisher Cast netting in 0.12 Medical attention Non-fatal, scars on 1.5 None
swampy areas right foot & left hand
6 June 2014 46 Unknown Swimming 12.61 Human remains recovered Fatal Unknown Killing of crocodiles by
under the by municipality & local people & crocodile
influence of federal authorities translocation by local
Human–crocodilian interactions
alcohol authorities
795796 G. A. González‐Desales et al.
area. Management strategies are now required for this been documented that anthropogenic activities such as swim-
crocodile population, as employed in and when ming, fishing, washing, walking near sources of water, sailing,
eggs were recovered from nesting areas within the estuary, catching crocodilians, falling into the water, bathing cattle,
with offspring reared from incubated eggs and collecting water or crossing a body of water, are the main
then released in the Reserve (Sigler et al., ). In other circumstances in which negative interactions occur between
regions of Mexico, habitat protection, nest and clutch people and crocodiles (Caldicott et al., ; Langley, ;
care, and long-term monitoring have helped the recovery Jayson et al., ; Dunham et al., ; Brien et al., ).
of C. acutus populations (García et al., ). Our findings indicate a relationship of negative human–
Since , following the incidents with crocodiles, crocodilian interactions with anthropogenic activities and
people living along El Hueyate estuary no longer engage the crocodile reproductive season (nesting and care of
in fish harpooning for fear of being attacked; they also des- hatchlings), and potentially to some socio-economic char-
troy crocodile eggs (Sigler & Martínez-Ibarra, ; Sigler acteristics of the municipalities where negative incidents
et al., ; González-Desales et al., a) and no longer occur. This is also the pattern on the Mexican Pacific
swim or bathe in the estuary. Negative human–crocodilian coast. Abundance of crocodilians does not appear to
interactions affect both parties (Table ; Pooley, ). People determine the frequency of negative interactions, but the
may suffer fatal incidents, temporary or permanent physical probability of negative interactions may increase in
and/or psychological damages, economic expenses and loss locations with more crocodile sightings. This should be
of domestic animals. The decline of a crocodile population considered in the safeguarding of tourists and the local
can affect the local economy directly, and negatively, as a population: monitoring of wild populations of C. acutus
result of an increase in species of mammals, birds and would help to establish whether there are more negative
arthropods considered problematic for agriculture (Cott, incidents at sites with greater numbers of crocodiles.
; Fittkau, ), and short-term ecological imbalance Consideration of the socio-economic characterization of
(Nifong, ). municipalities, and locating nesting zones, are the first
It is therefore important to collect data systematically, to steps required to identify risk sites and to implement
understand the dynamics of crocodile populations and to prevention strategies: for example, signage at risk sites
document their interactions with people and, subsequently, such as nesting areas and training of response groups for
to recommend actions that facilitate coexistence (Pooley, incidents with crocodiles.
). Ecotourism and sustainable harvest of crocodilian Negative interactions between people and crocodiles are
populations are potential management strategies (Fukuda increasing in Mexico (García-Grajales & Buenrostro-Silva,
et al., ). To conserve crocodiles, it is vital to involve all ), and the study of this phenomenon is necessary to sup-
stakeholders, including government agencies, non-govern- port public policies, possibly including the translocation or
mental organizations, business and tourism sectors, the removal of troublesome individual crocodiles. Conservation
media, and the public, both rural and urban. strategies need to consider the ecological, socio-economic
The majority (.%) of incidents occurred during Feb- and cultural aspects of these interactions, to avoid the illegal
ruary–September, the nesting season of C. acutus, which is killing of crocodiles (Carter et al., ). Public education
similar to Crocodylus palustris in India, where .% of about crocodiles needs to be improved, to inform people
incidents were reported during the breeding season (Vyas about high risk situations and how to avoid them, but it is
& Stevenson, ). The main local economic activity is fish- also imperative to convey why crocodiles need to be con-
ing within the estuary, close to nesting sites (Hernández- served (Pooley, ; Cureg et al., ; Sideleau et al., ).
Hurtado et al., ; Das & Jana, ). Although the Conveying this message to the diverse range of stakeholders
inhabitants in the study area suggested that the increase of could include various strategies such as the use of brochures,
crocodiles in the estuary is the main cause of negative pamphlets, signage, media coverage, posters, public presenta-
interactions, our findings suggest otherwise: negative in- tions and tourist guides (Amarasinghe et al., ).
teractions also occurred when crocodile abundance was Finally, we make the following recommendations: ()
low, such as in (Fig. ). Another important aspect to monitoring recreational activities near the sites and during
consider is a crocodile’s length (Fukuda et al., ): the the nesting season (depending on the site, February–
average size of the crocodiles responsible for negative September) by tourism service providers and institutions
interactions in Mexico was . m (range .–. m), and responsible for crocodile monitoring and administration
in cases the crocodiles were reported to be . m in of natural areas, () dissemination of information on the
length (CrocBITE, ). The crocodiles involved in the possible risk of incidents, () protection of eggs in incuba-
negative interactions in El Hueyate estuary measured .– tion pens, and () encouraging strategies to meet the social
. m in length (Table ), and the dates of the incidents and economic needs of the local human population. We
recorded corresponded to the months of courtship, nesting have implemented some of these strategies in El Hueyate
or care of neonates. In other species of crocodilians it has estuary, and so far there have not been any reports of
Oryx, 2021, 55(5), 791–799 © The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605319000668
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https://doi.org/10.1017/S0030605319000668Human–crocodilian interactions 797
further incidents. Signs are erected during the nesting sea- for understanding illegal killing of large carnivores. Ambio,
son, and nests were protected during – by local , –.
C A S A S -A N D R E U , G. () Ecología de la anidación de Crocodylus
people (García-Grajales et al., ). We are continuing
acutus (Reptilia: Crocodylidae) en la desembocadura del río
these activities. Cuixmala, Jalisco, México. Acta Zoológica Mexicana, , –.
C A S T I L LO , F.A. () American crocodile in the Central Pacific
Acknowledgments We thank Consejo Nacional de Ciencia y Region. Crocodile Specialist Group Newsletter, , .
Tecnología and the Universidad Autónoma del Estado de México C E D E Ñ O -V Á Z Q U E Z , J.R., P L AT T , S.G. & T H O R B J A R N A R S O N , J. ()
(Scholarship 360827, Project 3841/2014/CIA) for funding; sponsors Crocodylus moreletii. In The IUCN Red List of Threatened Species
of the Student Research Assistance Scheme for financing the field- : e.TA. dx.doi.org/./IUCN.UK..RLTS.
work through the IUCN Crocodile Specialist Group (Project 14/3); TA.en [accessed April ].
B. Sideleau for maintenance of CrocBITE; the people of La Encrucijada C E D I L LO -L E A L , C., G A R C Í A -G R A J A L E S , J., M A R T Í N E Z -G O N Z Á L E Z ,
Biosphere Reserve for sharing details of their problems with crocodiles; J.C., B R I O N E S -E N C I N I A , F. & C I E N F U E G O S -R I VA S , E. ()
the Island Conception ecotourism project for providing facilities during Aspectos ecológicos de la anidación de Crocodylus acutus (Reptilia:
fieldwork; and Xareni Pacheco for help with the text. Crocodylidae) en dos localidades de la costa de Oaxaca, México.
Acta Zoológica Mexicana, , –.
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GAG-D, MMZ-G, OM-V; fieldwork: GAG-D, LS; writing: all authors; composition of alligator population in Louisiana. Proceedings of
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