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Crocodylus intermedius (Orinoco crocodile): age at first reproduction

consumption as this might be an important way for hatchling C.
to behaviorally osmoregulate in saline environments
(Thorbjarnarson 1989.
In P. M. Hall [ed.], Crocodiles: Their
Ecology, Management, and Conservation, pp. 228-258. IUCN,
Gland, Switzerland).
Fischer et al. (1991. J. Herpetol. 25:253-256) contend that
Alligator mississippiensis
cannot effectively capture
small prey owing to a long snout in relation to body size (Mean
HL/SVL ratio = 0.31; S.E. = ± 0.001; N = 288), and instead rely
on metabolizing residual yolk as an energy source. However, no
significant difference exists between the HL/SVL ratio of C.
and A.
hatchlings (ANOVA;
312 =
P >
0.05), and the prevalence of prey remains among stomach contents
indicates C.
neonates are adept predators, which begin
feeding within 7 days of hatching. Therefore, failure of
hatchlings to capture small prey might not be
because of morphological constraints.
Submitted by
Wildlife Conservation
Society, 2300 Southern Boulevard, Bronx, New York 10460-1099,
USA (e-mail•
The Institute of Environmental and Human Health, Department
of Environmental Toxicology, Texas Tech University Box 41163,
Lubbock, Texas 79409-1163, USA (e-mail:
), and
THORBJARNARSON, Wildlife Conservation Society, 2300
Southern Boulevard, Bronx, New York 10460-1099, USA
(Orinoco Crocodile).
Hunting pressure has extirpated or
nearly extirpated many crocodilian populations. As a consequence,
conservation efforts in many countries have focused on both
protecting land and head-starting wild-caught or farmed neonates
which are then reintroduced to protected areas. Orinoco crocodiles,
Crocodylus intermedius,
were nearly extirpated in the Venezuelan
llanos prior to a ban on their commercial harvest during the 1970s
(Munoz and Thorbjarnarson 2000. J. Herpetol. 34:397-403;
Thorbjarnarson 1992. Crocodiles: An Action Plan for their
Conservation, IUCN/SSC. 136 pp.). Since 1990, conservation
efforts have resulted in the release of > 1300 juveniles in protected
private and public lands (C. Chavez, pers. comm.). To date, only
modest efforts have been devoted to assessing success of
reintroduced individuals. Available data show that animals survive
and remain in protected areas (Munoz and Thorbjarnarson,
but whether re-introduced individuals were reproducing was
uncertain. Here, we document the successful nesting of
reintroduced crocodiles in two large cattle ranches located in
Distrito Munoz, State of Apure, Venezuela (7°30'N, 69°18W).
Both ranches, Hatos El Frio (80,000 ha) and El Cedral (54,000
ha), are located in the flooded savannas of the Venezuelan Ilanos
that previously harbored
C. intermedius,
where hunting pressure
had locally extirpated the species (Arteaga and Hernandez 1996.
Proceedings of the 13th Working Meeting of the Crocodile
Specialist Group, pp. 207-222, IUCN). In 1990, an initial group
of 31 juveniles 1-4 years of age was released in Hato el Frio. In
1994, five juveniles were released in Hato El Cedral; four of these
were born in 1993 (sizes ranging roughly from 60 to 80 cm in
total length) and the remaining juvenile was between 3 and 5 years
old. These reintroduced juveniles were regularly observed, but lack
of appropriate nesting habitat in the near vicinity limited
opportunities for reproduction. As a result, from 1996 to 2001
management built artificial nesting sites. These artificial sites
consisted of —1 m
holes excavated in the edges of the water bodies
that were filled with river sand from beaches where C.
had nested historically.
In March 1998, we found the first two nests (52 and 56 eggs)
with fertile eggs. The females that laid these clutches were not
captured, so their age is uncertain; however, this site had animals
up to 12 years old. In March 2001, at least two of the females
released in El Cedral laid eggs. Clutch fertility (30+ eggs in one
case; predators destroyed the other nest) could not be assessed
because ranch workers mistakenly removed the eggs and they were
not incubated for any length of time.
Females that laid the eggs at El Cedral were not caught, but the
C. intermedius
present were from the 1994 release. Thus,
minimum reproductive age for females is no greater than 8 years
because only one older
C. intermedius
was known to be present
and two clutches were laid. Two of the released females caught in
January 2001 were 322 and 342 cm total length, and weighed 145
and 175+ kg, respectively.
Some release sites selected for
C. intermedius
have been on
public lands protected only on paper (Arteaga and Hernandez,
Munoz and Thorbjamarson,
op. cit.).
Fishing and poaching
have resulted, at best, in limited success for such public land re-
introductions. Our data show that re-introductions on private lands
where systematic protection is enforced can be successful, at least
over a few years. Continued investigation of this promising pattern
is needed to determine whether it will continue.
Estacion Cientifica Amigos de Doiiana, Available Light, The
National Geographic Society, and Association for Conservation
Research and Education provided funding and logistic support;
COVEGAN allowed us to work on their ranch; and Mauricio
Urcera, Jose Ayarzaguena, Tulio Aguilera, Carlos Chavez, Pedro
Azuaje, and John Thorbjarnarson helped in data collection .
Submitted by
National Geographic
Television, 1145 17th Street NW, Washington, D.C. 20036, USA
Sloan Canyon Road, Jamul, California 91935, USA.
(Gray Mole).
An unfortunate consequence of the huge diversity in the genus
Anolis (>
300 spp.; Guyer and Savage 1986. Syst. Zool. 35:509-
631) is that ecology of many species is unknown. Sparse knowledge
for anoles is marked in Mexico, where few taxa have been studied
(e.g., Ramirez-Bautista and Vitt 1997. Herpetologica 53:423-431).
Here, we address this gap through provision of a few data on the
infrequently observed anole
Anolis quercorum,
a species for which
no data have become available since its description from
Nochixtlan, Oaxaca, Mexico (Fitch 1978. Contrib. Biol. Geol.,
Milwaukee Pub. Mus. 20:1-15).
Over 4 days (14 May, 12 July, and 2 and 22 September 1998),
we collected six A.
(four females [field numbers: JLE
3004-5, 3024; and LOL 014] and two males [JLE 2551 and LOL
Herpetological Review 33(3), 2002
Full-text available
Los condríctios o peces cartilaginososestán considerados entrelos grupos marinos más amenazado a nivel mundial. Las principales causas dela reducción de sus poblaciones sonla sobre-explotación pesquera y la degradación de los hábitats. Venezuela posee una diversidad importante de condríctios, alrededor de100 especiesinventariadas, lo que corresponde aproximadamente al 50% de todas las especies reportadas para el Mar Caribe. No obstante, estudios previos realizados en aguas venezolanas apuntan hacia la disminución de la abundancia de varias especies importantes de condrictios, principalmente tiburones. En este sentido, se utilizaron los criterios de la Unión Internacional para la Conservación de la Naturaleza (UICN) con el propósito de determinar su riesgo de extinción. La evaluación se realizó con base en la información generada de registros y estudios científicos, dándole prioridad a lasespecies más críticas. En total se evaluaron 13especies, de las cuales 10correspondientesal grupo de los tiburones y tresde batoideos. Con relación al estadode conservación de las especies evaluadas, dosfueron incluidas en el nivelEnPeligro Crítico, dosEn Peligro,y 9comoVulnerables.Entre las amenazas identificadas se encuentran la sobre-explotación pesquera llevada a cabo sin ningún tipo de control, la captura de proporciones elevadas de ejemplares juveniles y la degradación de los hábitats esenciales. Se recomienda alosentesencargadosde la ordenación de los recursos pesqueros tomar en cuenta el estatus de estas especies en los futuros planes de manejo
Full-text available
Populations of the Orinoco crocodile (Crocodylus intermedius) have not recovered from past exploitation, and current abundances cannot be used for assessing the suitability of habitats they occupy. Growth constitutes an alternative way of assessing habitat quality. Since 1990, more than 9000 captive-reared Orinoco crocodiles have been released into the Venezuelan Llanos. In the present study, the growth rates of 127 recaptured crocodiles from different regions were compared. All individuals from Middle Cojedes and the Aeolian savannahs grew slower than expected by the von Bertalanffy model, whereas individuals from Caños in the Apure floodplains grew faster than expected. These inferences are corroborated with growth rate measurements for crocodiles under four years of age, which were lowest in Middle Cojedes (average of 14.1 cm/ year) and highest at Caños (43.3 cm/year). Low growth rates can be explained by habitat deterioration due to human activities, and high growth rates in the Caños support that the lower reaches of whitewater rivers offer favourable conditions for the species. Crocodiles in high quality habitats may reach sexual maturity in six years, whereas more than a decade is required in poor-quality habitats. Key words: growth models, habitat quality, Orinoco crocodile, reintroduction
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