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2010 SOUTHEASTERN NATURALIST 9(4):711–720
Natural History of Resident and Translocated Alligator
Snapping Turtles (Macrochelys temminckii) in Louisiana
Victor Bogosian III*
Abstract - Translocation is often considered a viable conservation strategy, despite
the absence of species-specific post-translocation data. Macrochelys temminckii (Alligator
Snapping Turtle) populations have declined across their range and they may be
considered candidates for translocation, but few studies have examined the response
of individuals to movement events. I monitored M. temminckii with radiotelemetry
in northwest Louisiana to provide baseline data regarding the species’ response to
translocation. I calculated average distances moved per day, measured water depths,
and recorded growth of translocated and resident turtles. There was no observed
mortality during the study, and translocated turtles gained mass and increased shell
dimensions, indicating they effectively located resources after translocation. Resident
individual shell dimensions increased, but some residents lost mass, possibly
due to early recapture and reweighing dates. Movement distances were within the
ranges reported by previous researchers. These data contribute baseline information
concerning M. temminckii conservation biology.
Many species of freshwater turtles are critically endangered due to
anthropogenic factors (Browne and Hecnar 2007, Garber and Burger
1995), some to the extent that their continued existence may be restricted
to captive populations (Gibbons et al. 2000). Recolonization rates may be
low due to life-history strategies in some species (Congdon et al. 1993,
1994). In these cases, reintroduction (the movement of individuals within
their native range to localities where the species has been extirpated) or
translocation (the movement of individuals to localities where the species
has not been extirpated) may increase overall population recovery (Gibbons
et al. 2000, Tuberville et al. 2005), although these attempts carry
with them a great deal of uncertainty. In many published translocation
attempts, further investigations of natural history and refinement of translocation
techniques are suggested by the authors (Berry 1986, Tuberville
et al. 2005).
Macrochelys temminckii Harlan (Alligator Snapping Turtle) is a largebodied
(>100 kg), long-lived species found in the southeastern United States
(Pritchard 1989). Large-scale commercial exploitation of M. temminckii
during 1960–1980 (Roman et al. 1999) resulted in the collapse of commercially
viable populations and enaction of protective laws (Pritchard 1989,
*Museum of Life Sciences, Louisiana State University in Shreveport, One University
Place, Shreveport, LA 71115-2399. Current address - Cooperative Wildlife Research
Laboratory, Southern Illinois University, Carbondale, IL; email@example.com.
712 Southeastern Naturalist Vol. 9, No. 4
Reed et al. 2002). Commercially preferred minimum body size for profitable
butchering coincided with the onset of sexual maturation in M. temminckii
(Sloan and Lovich 1995, Tucker and Sloan 1997), and the number of turtles
processed annually during this time was very high (Sloan and Lovich 1995).
Macrochelys temminckii populations are now protected from commercial
harvest across their range (Boundy and Kennedy 2006), suggesting that
populations may eventually recover if commercial overharvesting was the
primary factor in their decline.
Encouraging evidence exists regarding turtle population recovery following
removal of factors associated with declines (Gibbs et al. 2008),
but demographic models predict that natural recovery of M. temminckii
populations may be a lengthy process (Reed et al. 2002). An additional
concern for any translocation attempt is the definition and estimation of
success. Griffith et al. (1989) defined a successful translocation event
as one that presents evidence of a stable, self-sustaining population.
These criteria are difficult to confirm for M. temminckii given their long
lifespans and delayed sexual maturity (Dobie 1971), as well as the cryptic
nature of younger age classes (Boundy and Kennedy 2006); indeed,
these criteria are difficult to confirm in unharvested, stable populations.
Therefore, acceptance of other metrics of determinants for success of
reintroductions of M. temminckii is required, at least in the preliminary
stages of conservation actions.
I collected movement and location depths following release of resident
and translocated turtles at two sites. Small sample size prevented statistical
interpretation, but these data may serve as baseline metrics of acclimation
to unfamiliar locations. Movement by turtles occurs to satisfy physiological
requirements, avoid predators, capture prey, locate suitable habitats,
and fulfill reproductive requirements (Gibbons et al. 1990). Movement behavior
is commonly used in turtle research as an estimate of an individual’s
acceptance or rejection of its surroundings following translocation (Cook
2004, Field et al. 2007, Rittenhouse et al. 2007). Movements of translocated
turtles are often longer and more frequent than that of resident turtles
(Hester et al. 2008, Rittenhouse et al. 2007), and individuals may disperse
from the release site before establishing home ranges (Berry 1986). I also
report data on overwintering duration and the growth of individuals during
the monitoring period. This information is intended to build upon a body of
literature that may be used by future conservation biologists whose efforts
are intended to establish stable, self-sustaining populations (Griffith et al.
1989) of M. temminckii.
My study sites were near Shreveport, LA, and included Cross Lake
(approximately bounded geographically by 32.50° and 32.54°N, and
2010 V. Bogosian 713
93.78° and 93.97°W; 3400 ha) and an unnamed lake in the Red River
National Wildlife Refuge (RRNWR hereafter, approximately bounded
geographically by 32.44° and 32.45°N, and 93.66° and 93.68°W; 80 ha).
The RRNWR (translocation site) was a natural oxbow of the Red River.
It contained dead flooded Salix spp. (willows) in the lake, was vegetated
by a mixture of willows and Quercus spp. (oaks) along the shoreline, and
had water depths of 0.5–6.0 m. Shallower portions of the RRNWR were
vegetated heavily by Nelumbo lutea Willd (American Lotus) and Ceratophyllum
demersum L. (Coontail), and experienced sporadic drying during
years with low rainfall. To facilitate recapturing translocated turtles at the
end of the study, I selected the translocation site due to its isolation from
dispersal routes and its lack of resident M. temminckii populations. Cross
Lake (resident site) is a similarly shallow (0.5–3.0 m range) impoundment
dammed on the eastern edge. The western half was dominated by
Taxodium distichum (L.) Rich. (Baldcypress)-Cephalanthus occidentalis
L. (Buttonbush) swamps, and both submergent (C. demersum) and
floating (Eichornia crassipes Mart. [Water Hyacinth]) vegetation were
common understory components. Although Cross Lake is much larger
and thus experiences less periodic drying than the RRNWR, it serves as a
municipal water source for Shreveport and typically experiences reduced
water levels in late summer and early autumn.
I trapped turtles during March–October 2005 using single-throated
hoop nets (0.9 m diameter, 2 m length, 2.5 cm mesh size; Memphis Net and
Twine, Memphis, TN). Traps were baited with frozen tilapia, Lepisosteus
spp. (gar), or canned Thunnus spp. (tuna), and checked daily. Macrochelys
temminckii were brought to the laboratory for transmitter attachment and
measurement, and all other captured turtles were released immediately.
Two M. temminckii (1 male, 1 female) were acquired from commercial
trappers in August 2004, and one was captured by hand at Cross Lake in
October 2005. The trappers were reluctant to divulge their trap sites, so I
could not determine the exact location of capture for acquired turtles, and
considered them to be translocated.
Radiotransmitters (Holohil Inc., ON, Canada) were attached to the
middle of the carapace using quick-drying marine epoxy. I measured
straight-line carapace length (CL) using forestry calipers (± 1 mm, Forestry
Supply Company, Jackson, MS) and mass using a Pesola scale (± 0.1 kg) for
each individual, and classified turtles as adults or subadults based on measurement
partitions provided by Dobie (1971). I did not attempt to determine
the gender of subadult turtles, and determined the gender of adult turtles
via preanal tail length (Dobie 1971). To permanently identify individuals,
PIT tags (Biomark, Inc., Boise, ID) were injected into the tail musculature.
714 Southeastern Naturalist Vol. 9, No. 4
Some turtles were held in captivity for extended periods of time before their
release (Table 1). Long-term captive individuals were housed at the Natchitoches
National Fish Hatchery and were offered dead fish on a weekly to
bi-weekly basis. Shorter-term captive individuals were housed in metal or
plastic containers at the Louisiana State University in Shreveport Museum
of Life Science and were also offered fish weekly to bi-weekly. Remaining
individuals were housed similarly as shorter-term captives and released
within 1–2 days of capture.
I released resident turtles at their capture locations, and released
translocated turtles at a single location at the edge of the shoreline at the
RRNWR. Turtles were tracked 1–4 times per week during May–October
(2005) and March–April (2006), and 1–2 times every 2 weeks during
November–February (2005–2006), all time and weather permitting.
Turtles were relocated from a 4.3-m boat using an R-1000 receiver (Communications
Specialists, Inc., Orange, CA) and folding 3-element Yagi
antenna (Wildlife Materials, Inc., Murphysboro, IL). The location of each
telemetry check was recorded with a handheld GPS unit (Trimble GeoXT,
ArcPad 6.1, ± 1 m accuracy) and water depth was measured using a lead
line (± 0.1 m). I recaptured telemetered turtles using nets, poles, and by
hand during March–April 2006. Recaptured turtles were re-weighed and
measured, and their transmitters and all epoxy residue removed. Resident
turtles were released at their last point of telemetry relocation, and
translocated turtles that were recovered were released at their last known
location of native capture.
I determined distance moved between relocations using ArcView 3.3
(ESRI, Redlands, CA). Because of the highly aquatic nature of M. temminckii
(Reed et al. 2002), movement paths were restricted to aquatic
routes (i.e., paths between two locations were not allowed to cross land).
I divided the distance between relocation points by the number of days
between each relocation event (corrected movement distance). Individual
M. temminckii become sedentary during the colder winter months and
may exhibit long periods of inactivity or little movement (Harrel et al.
1996, Riedle et al. 2006). I did not include inactive season movements/
non-movements or depths when calculating summary statistics. A turtle
was defined as inactive if it did not move for >1 week during the months
Results and Discussion
I captured 8 M. temminckii (7 in hoop nets, 1 by hand at Cross Lake).
In addition, 2 acquired individuals provided a telemetry sample size of 10
(7 resident and 3 translocated turtles). One subadult animal was lost from telemetric
monitoring for 19 days before being located 7 km away. To account
for this unusually large movement, I report data for resident individuals both
2010 V. Bogosian 715
Table 1. Residency status and morphology of telemetered turtles near Shreveport, LA, 2005–2006. † indicates individuals acquired from commercial trappers
Turtle Capture Days in Residency Initial Initial Recapture Final Final CL growth Mass change
ID Sex date captivity status CL (cm) mass (kg) date CL (cm) mass (kg) (cm/wk) (kg/wk)
170 Male 10/25/2005 2 Resident 46.6 25.8 3/25/2006 46.6 25.5 0.000 -0.014
206 Male 5/2/2005 1 Resident 40.0 17.8 Radio detachment - - - -
231 Subadult 8/8/2005 1 Translocated 25.6 4.1 4/1/2006 26.6 4.2 0.021 0.003
253 Female 8/13/2005 2 Resident 39.8 15.4 4/11/2006 39.8 15.2 0.000 -0.006
271 Female 8/14/2005 2 Resident 35.0 10.4 3/21/2006 35.0 9.2 0.000 -0.039
311 Subadult 3/26/2005 36 Resident 25.8 4.5 4/21/2006 26.3 4.8 0.010 0.006
331 Male † ≥259 Translocated 43.0 22.1 Radio detachment - - - -
353 Female † ≥259 Translocated 36.9 13.0 3/28/2006 37.4 13.2 0.011 0.004
371 Male 3/23/2005 39 Resident 44.3 21.3 3/25/2006 45.0 22.2 0.015 0.019
396 Subadult 3/26/2005 36 Resident 32.7 9.1 3/31/2006 33.3 9.2 0.013 0.002
716 Southeastern Naturalist Vol. 9, No. 4
with and without this individual (where applicable, bracketed data values are
means and standard errors that do not include this individual). I obtained 458
telemetry observations, but censored the dataset to include only 288 (248
without the wide-ranging individual) active-season relocations. Observed
corrected movement distances (Table 2) were within ranges published in
other studies of M. temminckii in Louisiana (resident: 59.4 ± 7.2 m [56.7 ±
7.7 m]; translocated: 60.3 ± 11.9 m), but movement frequency rates were
higher than those reported in the literature (84.8 [80.0] and 79.6%, resident
and translocated turtles, respectively, compared to a range of values of
26.8 – 65.0% for subadult male and female turtles [Harrel et al. 1996]). The
daily movement distances I observed were much lower than those reported
by Riedle et al. (2006), potentially due to their study being conducted in a
series of small creeks versus the impounded lake my study was conducted in.
I could not compare my movement frequency data with Riedle et al. (2006)
due to data reporting discrepancies. Turtles in my study may have moved
more due to variation in study sites (i.e., Harrel et al.  studied turtles in
a flowing water system, and I studied turtles in impoundments). Turtles may
have moved more often than telemetry checks detected due to observation
rates of less than 1 check per day. Depths selected by resident (0.81 ± 0.03 m [0.80
± 0.03]) and translocated (1.1 ± 0.2 m) turtles were shallower than values
reported by Harrel et al. (1996).
I was unable to recapture 2 individuals (both adult males, one per treatment
group) due to transmitter detachment. Both recaptured translocated
individuals (n = 2) increased in CL (0.016 ± 0.008 cm/week) and mass (0.004
± 0.001 kg/week), whereas 3 of 6 resident individuals exhibited no growth in
CL and lost mass (Table 1). Some turtles (n = 4; 1 translocated, 3 residents)
made short (less than 19 m daily corrected distance) and infrequent (< 2 observed
movements per individual of both treatment classes) movements during the
inactive period. Residency status did not appear to affect the time spent inactive
(resident: 100.6 ± 7.1 days, translocated: 107.7 ± 6.2 days).
Previous research on the movement of M. temminckii has indicated a
tendency to return to the same area and microsites (Harrel et al. 1996, Riedle
Table 2. Movement of telemetered turtles near Shreveport, LA, 2005–2006.
Turtle ID Sex n movements Mean ± SE m/day
170 Male 11 32.1 ± 8.3
206 Male 43 28.2 ± 4.6
231 Subadult 24 18.4 ± 1.7
253 Female 27 44.0 ± 13.1
271 Female 19 38.1 ± 10.9
311 Subadult 39 71.7 ± 19.6
331 Male 38 77.7 ± 26.4
353 Female 41 84.7 ± 14.6
371 Male 39 143.3 ± 29.9
396 Subadult 46 31.0 ± 7.4
2010 V. Bogosian 717
et al. 2006, Sloan and Taylor 1987). Overall, my observations did not detect
many instances of movement away from and returning to a specific site, but
the low frequency of telemetry observations may have missed short forays
away from a preferred location. Individuals occasionally returned to the
same approximate areas, but I did not find them at the same structure more
Homing is often exhibited by terrestrial chelonians (Berry 1986) and
occasionally by aquatic chelonians (DeRosa and Taylor 1980) after translocation.
The origin of some translocated turtles in this study was unknown,
and intentionally attempting to prevent homing response by translocationsite
selection prevents interpretation of movement in terms of homing. Large
movement distances were noted for one turtle (individual 331) following
release at the RRNWR, but these were not consistently in any one direction.
The other translocated individuals did not move as far in the first 24
hours following release. Additionally, long-distance movement of resident
M. temminckii have been observed by researchers (Boundy and Kennedy
2006, Riedle et al. 2006), suggesting that occasional long movements may
be typical behavior for some individuals.
Translocated turtles did not select the deepest habitat available. The
translocation site did not have high availability of cypress-buttonbush habitat
(or equivalent overhanging canopy), which M. temminckii prefer (Harrel
et al. 1996, Howey and Dinkelacker 2009, Sloan and Taylor 1987, Riedle et
al. 2006), whereas the resident site did. Use of areas with overhanging vegetation
by M. temminckii is probably related to physiological requirements
(i.e., thermoregulation; Riedle et al. 2006), but the lack of such habitat at the
translocation site did not appear to cause turtles to occupy deeper portions of
the lake. The influence of a high drought period most likely influenced depth
use by all turtles in this study. In the late summer of 2005, both study sites
experienced considerable water depth reduction due to drought. Summer
2005 was one of the lowest periods of rainfall on record for the Shreveport
area (National Climatic Data Center, www.ncdc.noaa.gov), and all study
sites experienced mild to moderate desiccation, but experienced high rainfall
events during hurricanes in the fall. These unusual hydrologic events may
have influenced movements and depth occupancy.
The rates of growth and mass change were probably influenced by several
factors, including age class, period of observation, and date of recapture.
The fact that relocated individuals gained mass and length indicates that they
can effectively forage in novel environments. The growth rates were lower
than reported mean growth values (0.03 cm/week CL, n = 3; Harrel et al.
1997) for M. temminckii for either treatment group, potentially due to shorter
monitoring periods and time in captivity. Overwinter survival of translocated
individuals taken together with increased mass and shell dimensions the following
spring suggests translocated individuals were able to locate suitable
718 Southeastern Naturalist Vol. 9, No. 4
My results suggest that translocated M. temminckii can find suitable
habitat to experience growth despite abundant non-preferred habitat types
at release sites. However, these results can only be interpreted in shortterm
temporal settings. Premature claims of success have been noted in
literature involving herpetofauna translocation (Dodd and Seigel 1991),
and interpretation of these results as support for translocation of M. temminckii
without further research or longer post-release monitoring is
discouraged. Additional data (i.e., population structure, rates of dispersal,
nesting and recruitment rates) must be collected and analyzed from both
resident and translocated populations before managers and scientists
can determine if conservation resources are best used in attempting to
re-establish M. temminckii populations by headstarting programs, translocations,
All research activities were funded by a Louisiana Department of Wildlife and
Fisheries grant (state wildlife grant T24, M. McCallum, initial principal investigator
, L.M. Hardy, principal investigator [2005–2006]) and were conducted according
to guidelines provided by the Society for the Study of Amphibians and Reptiles.
Assistance in the field and laboratory was rendered by A. Crnkovic, M. Hamilton,
J. Lewis, M. Lewis, A. Menasco, R. Menasco, H. Neve, N. Neve, C. Spaulding, H.
Spaulding, C. Sumner, J. Waguespack, and E. Walsh. Assistance with boat motors
was provided by J. Bertrand and A. Vekovius. E.C. Hellgren reviewed early drafts of
Berry, K.H. 1986. Desert Tortoise (Gopherus agassizii) relocation: Implications of
social behavior and movements. Herpetologica 42:113–125.
Boundy, J., and C. Kennedy. 2006. Trapping survey results for the Alligator Snapping
Turtle (Macrochelys temminckii) in southeastern Louisiana, with comments
on exploitation. Chelonian Conservation and Biology 5:3–9.
Browne, C.L., and S.J. Hecnar. 2007. Species loss and shifting population structure
of freshwater turtles despite habitat protection. Biological Conservation
Congdon, J.D., A.E. Dunham, and R.C. Van Loben Sels. 1993. Delayed sexual maturity
and demographics of Blanding's Turtles (Emydoidea blandingii): Implications
for conservation and management of long-lived organisms. Conservation
Congdon, J.D., A.E. Dunham, and R.C. Van Loben Sels. 1994. Demographics of
Common Snapping Turtles (Chelydra serpentina): Implications for conservation
and management of long-lived organisms. American Zoologist 34:397–408.
Cook, R.P. 2004. Dispersal, home-range establishment, survival, and reproduction
of translocated Eastern Box Turtles, Terrapene c. carolina. Applied Herpetology
DeRosa, C.T., and D.H. Taylor. 1980. Homeward orientation mechanisms in three
species of turtles (Trionyx spinifer, Chrysemys picta, and Terrapene carolina).
Behavioral Ecology and Sociobiology 7:15–23.
2010 V. Bogosian 719
Dobie, J.L. 1971. Reproduction and growth in the Alligator Snapping Turtle, Macroclemys
temmincki (Troost). Copeia 1971:645–658.
Dodd, C.K., Jr., and R.A. Seigel. 1991. Relocation, repatriation, and translocation
of amphibians and reptiles: Are they conservation strategies that work? Herpetologica
Field, K.J., C.R. Tracy, P.A. Medica, R.W. Marlow, and P.S. Corn. 2007. Return to
the wild: Translocation as a tool in conservation of the Desert Tortoise (Gopherus
agassizii). Biological Conservation 136: 232–245.
Garber, S.D., and J. Burger. 1995. A 20-yr study documenting the relationship between
turtle decline and human recreation. Ecological Applications 5:1151–1162.
Gibbons, J.W., J.L. Greene, and J. Congdon. 1990. Temporal and spatial movement
patterns of sliders and other turtles. Pp. 201–215, In J.W. Gibbons (Ed.). Life History
and Ecology of the Slider Turtle. Smithsonian Institution Press, Washington,
DC. 368 pp.
Gibbons, J.W., D.E. Scott, T.J. Ryan, K.A. Buhlmann, T.D. Tuberville, B.S. Metts,
J.L. Greene, T. Mills, Y. Leiden, S. Poppy, and C.T. Winne. 2000. The global
decline of reptiles, déjà vu amphibians. Bioscience 50:653–666.
Gibbs, J.P., C. Marquez, and E.J. Sterling. 2008. The role of endangered species
reintroduction in ecosystem restoration: Tortoise-cactus interactions on Española
Island, Galápagos. Restoration Ecology 16:88–93.
Griffith, B., J.M. Scott, J.W. Carpenter, and C. Reed. 1989. Translocation as a species
conservation tool: Status and strategy. Science 245:477–480.
Harrel, J.B., C.M. Allen, and S.J. Hebert. 1996. Movements and habitat use of subadult
Alligator Snapping Turtles (Macroclemys temminckii) in Louisiana. American
Midland Naturalist 135:60–67.
Harrel, J.B., C.M. Allen, and S.J. Hebert. 1997. One year growth of subadult Macroclemys
temminckii in a Louisiana bayou. Herpetological Review 28:128–129.
Hester, J.M., S.J. Price, and M.E. Dorcas. 2008. Effects of relocation on movements
and home ranges of Eastern Box Turtles. Journal of Wildlife Management
Howey, C.A.F., and S.A. Dinkelacker. 2009. Habitat selection of the Alligator Snapping
Turtle (Macrochelys temminckii) in Arkansas. Journal of Herpetology 43:
Pritchard, P.C.H. 1989. The Alligator Snapping Turtle: Biology and Conservation.
Milwaukee Public Museum, Milwaukee, WI. 104 pp.
Reed, R.N., J. Congdon, and J.W. Gibbons. 2002. The Alligator Snapping Turtle
(Macrochelys [Macroclemys] temminckii): A review of ecology, life history, and
conservation, with demographic analyses of the sustainability of take from wild
populations. US Fish and Wildlife Service Report:1–17.
Riedle, J.D., P.A. Shipman, S.F. Fox, and D.M. Leslie Jr. 2006. Microhabitat use,
home range, and movements of the Alligator Snapping Turtle, Macrochelys temminckii,
in Oklahoma. Southwestern Naturalist 51:35–40.
Rittenhouse, C.D., J.J. Millspaugh, M.W. Hubbard, and S.L. Sheriff. 2007. Movements
of translocated and resident Three-toed Box Turtles. Journal of Herpetology
Roman, J., S.D. Santhuff, P.E. Moler, and B.W. Bowen. 1999. Population structure
and cryptic evolutionary units in the Alligator Snapping Turtle. Conservation
720 Southeastern Naturalist Vol. 9, No. 4
Sloan, K., and J.E. Lovich. 1995. Exploitation of the Alligator Snapping Turtle,
Macroclemys temminckii, in Louisiana: A case study. Chelonian Conservation
and Biology 1:221–222.
Sloan, K., and D. Taylor. 1987. Habitats and movements of adult Alligator Snapping
Turtles in Louisiana. Proceedings of the Annual Conference of the Southeastern
Assocation of Fish and Wildlife Agencies 41:343–348.
Tuberville, T.D., E.E. Clark, K.A. Buhlmann, and J.W. Gibbons. 2005. Translocation
as a conservation tool: Site fidelity and movement of repatriated Gopher
Tortoises (Gopherus polyphemus). Animal Conservation 8:349–358.
Tucker, A.D., and K.N. Sloan. 1997. Growth and reproductive estimates from Alligator
Snapping Turtles, Macroclemys temminckii, taken by commercial harvest in
Louisiana. Chelonian Conservation and Biology 2:587–592.