Eunectes murinus (green anaconda). Longevity

Full text

mail: madridherp@aol.com) and
CARLOS
JESUS
BALDERAS
VALDIVIA (e-mail: cjbv@servidor.unam.mx), Laboratorio de
Biodiversidad, Direcci6n General de Divulgaci6n de
la
Ciencia,
Universmn,
UNAM,
Zona
Cultural Universitaria,
CP
04510,
Mexico, D.F.
CROTALUS
RA
VUS (Mexican Pygmy Rattlesnake).
DIET.
There
are few reports regarding the feeding habits
of
Crotalus ravus.
However, lizards (Sceloporus grammicus, S. megalepidurus),
mammals (Mus musculus, Microtus mexicanus), and insects (He-
miptera and Orthoptera) have been reported in the diet
of
this spe-
cies (Uribe-Pena et al. 1999. Anfibios y Reptiles de las Serranfas
del Distrito Federal, Mexico. Instituto de Biologfa, Universidad
Nacional Aut6noma de Mexico. 119 pp.; Mendoza-Hernandez et
al. 2004. Herpetol. Rev. 35:63).
In May 2001 we found a C. ravus at the base
of
a cactus ( Opuntia
sp.) near
La
Preciosa Lake (19 .3678°N, 97 .3867°W, WGS84; 2040
m), Las Minas,Puebla State,Mexico. The snake was eating an adult
Sceloporus spinosus. Photographic vouchers (MZFC 1604--05) are
in the Herpetological Collection
of
Museo de Zoologia, Facultad
de Ciencias, Universidad Nacional Aut6noma de Mexico.
Furthermore, on 12 May 2007 we collected an adult female
C. ravus (167
mm
SVL, 186
mm
TL), in Delegaci6n Magdalena
Contreras (19 .2879°N, 99 .2670°W, WGS84; 2580 m) in the south-
ern mountains
of
Distrito Federal, Mexico. The specimen (MZFC
20902) was found crossing a trail in oak forest. A fragment
of
a
snake tail was found in the snake's stomach.
We
identified the prey
as
Thamnophis scalaris, by comparing the tail fragment to the tails
of
other snakes collected in the same area. This is the first report
of
a snake in the diet
of
C. ravus.
We
thank Manejo de Ecosistemas y Desarrollo Humano, Uni-
versidad Nacional Aut6noma de Mexico (SDEI-PTID-02) for
financial support.
Submitted by ISRAELSOLANO-ZAVALETA(e-mail: crota-
lus.viper@gmail.com),
URI
OMAR
GARCIA-VAZQUEZ
and
MARTHA
L.
CALDERON-ESPINOSA,
Museo de Zoologfa,
Facultad de Ciencias, Universidad Nacional Aut6noma de Mexico,
Apartado Postal 70-399, Mexico, Distrito Federal 04510, Mexi-
co.
EUNECTES
MURINUS
(Green Anaconda).
LONGEVITY.
Anacondas and other large reptiles tend to live many years and
grow slowly later in life. However, long-term data on growth
rates for wild snakes are in short supply. Here we report recapture
of
a Eunectes murinus after
13
years. These observations were
made in the course
of
conducting an on-going mark-recapture
project (running since 1992) in the Venezuelan llanos, Distrito
M uiioz' A pure
state
(7
.5°N' 69
.3
°W). All snakes were marked
using scale clipping and by copying the ventral pattern covering
the first
15
subcaudal scales (Rivas
et
al. 2007. In Henderson and
Powell [eds.], Biology
of
the Boas and Pythons, pp. 128-138.
Eagle Mountain Publishing Company, Eagle Mountain, Utah).
On 27 August 1994 we captured a female (E548, 324 cm
SVL,
21
kg). Thirteen years later on
19
March 2007, we caught
E548 again and although the scale clipping mark was difficult
to
read,
we
were able to identify the individual unequivocally
by comparing the subcaudal pattern with our records. Upon
recapture E548 measured 366
cm
SVL and 25 kg. E548 was
wounded, weakened, and had a subcutaneous nematode (possibly
Dracunculus sp.) which has been found in other individuals in
this population (Calle et al. 1994.
J.
Zoo. Wild. Med. 25:53-64).
This may be the longest recapture record
of
any individual
snake in the wild. Twelve-year recaptures have been reported
by Madsen and Shine (2000. J. Anim. Ecol. 69:952-958).
It
is
surprising that in
13
years E548 only grew 42 cm.
It
is expected
that the growth rate
of
large reptiles will decrease towards older
age (e.g., Madsen and Shine, op. cit.),
butE548
is still far from the
largest size recorded for this region (exceeding 500 cm, Rivas et
al., op. cit.) and even further from other literature records. Cursory
evaluation
of
our mark/recapture data suggest that anacondas in
the wild may take more than a decade to reach 320 cm SVL, so
E548 could be in her mid-twenties or perhaps even older.
The harvest
of
anacondas have been present for more than
two decades driven largely by demand for luxury snakeskin
products in the global market (Waller
et
al. 2007. In Henderson
and Powell [eds.], Biology
of
the Boas and Pythons, pp. 340-362.
Eagle Mountain Publishing Company, Eagle Mountain, Utah).
However, rural populations may also be increasing their harvest
in response to changes associated with macroeconomic packages
that are affecting much
of
South America (Rivas 2007. Iguana.
14:
10-21). Nevertheless, a recent three-year study monitored the
experimental harvest
of
wild Eunectes noteus (Yellow Anaconda)
and concluded that harvest could be sustainable based primarily
on high reproductive i:ates, large distribution, and low human
density (Waller et al., op. cit.). However,
if
the extremely slow
growth rate presented here is the norm, we believe that the notion
of
sustainability is suspect in regions with high harvest/mortality
(see Rivas, op. cit.; Rivas et al. 1999. Herpetol. Rev. 30:101;
Rivas 2000. Unpubl. Ph.D. dissertation, University
of
Tennessee.
287 pp.; Rivas et al. 2001. Herpetol. Rev. 32:107-108).
We thank the Wildlife Conservation Society, Zoo de Doue la
Fontaine-France, Miami Metro Zoo,Anaconda Investments LLC,
COVEGAN,
J.
and T. Dunbar, and T. Hughes for assistance.
Submitted by
JESUS
A. RIVAS, Department
of
Math and
Natural Sciences, Somerset Community College, 808 Monticello
Street,Somerset,Kentucky42501,
USA;andSARAHJ.COREY,
Department
of
Evolution, Ecology, and Organismal Biology, The
Ohio State University, 318
W.
12'h
Avenue, Columbus, Ohio
43210, USA.
FARANCIA
ABACURA
(Mud Snake).
PREDATION
. Few re-
cords exist regarding predators
of
Farancia. Palmer and Braswell
(1995. Reptiles
of
North Carolina. University
of
North Carolina
Press, Chapel Hill) report
ed
that American Alligators (Alligator
mississippiensis) and Cottonmouths (Agkistrodon piscivorus)
consumed Farancia abacura and these appear
to
be their only
documented predators. It has been suggested that birds
of
prey
and wading birds predate
mud
snakes (Ernst and Ernst 2004.
The Snakes
of
the United States and Canada. Smithsonian Press,
Washington, D.C.) and birds have been used experimentally to
elicit death feigning (Doody et al. 1996. Herpetol. Rev. 27: 82-83).
However, there are no records
of
birds preying upon Mud Snakes
in
situ.
Herpetological Review 39(4), 2008 469