Site by Bennett Web & Design Co.
724060 6 NOSoRuTthHeEaAstSeTrnE RNNat uNrAaTliUstR NAoLteISsT V13o(l.1 8):,3 N9–o4. 24
Long-distance Displacement of a Juvenile Alligator by
Ruth M. Elsey1,* and Chelsea Aldrich2
Abstract - When Hurricane Ike made landfall near Galveston, Texas on 13 September 2008,
massive debris piles were formed onshore along coastal Louisiana and Texas. A live juvenile
Alligator mississippiensis (American Alligator) was found on 28 September amongst debris
on the beach at Padre Island National Seashore; this alligator had been marked (web tags and
tail notches) and released in Johnson’s Bayou, LA six weeks prior to the hurricane. We believe
it was swept away from coastal Louisiana by the hurricane’s storm surge and displaced some
489 km from its release site. To our knowledge, this is a record displacement for an American
Alligator and demonstrates the resiliency of this species.
Alligator mississippiensis Daudin (American Alligator) occurs in the southeastern
United States, and is common in coastal marshes adjacent to the Gulf of Mexico
(Joanen and McNease 1987). Although alligators occur in marshes of varying salinity
levels, they prefer wetlands of lower salinities or freshwater marshes; nesting in
salt marshes is rare (Elsey and Kinler 2004). Alligators can briefl y tolerate higher
salinities and have been documented offshore; we previously described an alligator
far offshore in the Gulf of Mexico, some 63 km from the nearest point on mainland
Louisiana (Elsey 2005). However, in general, alligators quickly suffer physiological
stresses when exposed to increasingly saline waters (Elsey et al. 2006, Lance et al.
2001, Lauren 1985, Morici 1996).
Hurricane Ike was a massive Category 2 storm on the Saffir-Simpson hurricane
scale (with winds of 154–177 km/hr) that made landfall near Galveston, TX on 13
September 2008. The unusually large wind field caused very high storm surges,
comparable to a Category 4 storm (winds of 210–249 km/hr). Hurricane force winds
occurred 193 km from the center of the storm, and tropical storm force winds extended
some 443 km from the storm’s center. High tides led to inundation of coastal
highways in southwest Louisiana hours in advance of actual landfall in Texas.
On 28 September 2008, a visitor found a juvenile American Alligator along with
other debris on the beach at Padre Island National Seashore (PAIS), near beach mile
marker 35. The alligator appeared markedly dehydrated and emaciated; with sunken
eyes, protuberant ribs and little strength, although it did respond with aggressive
hissing to slight provocation or disturbance. Other than a small wound/abrasion on
the tail, there were no obvious signs of external trauma, though internal injuries could
not be ruled out. There was an old amputation of the right upper limb, but it was well
healed. The alligator was not measured, but was estimated to be “about three feet”
(one meter) in length.
It was taken to park headquarters and brought to the attention of the National Park
Service staff member on duty (C. Aldrich). The park ranger noted the alligator was
marked with tail notches and had web tags placed between the toes of the rear feet.
These markings were subsequently noted to have been placed by biological staff of
the Louisiana Department of Wildlife and Fisheries.
Several attempts were made to provide fresh water to the alligator, but it did not
readily appear to drink or ingest much water. No attempts were made to feed the alligator.
The National Park Service ranger (CA), upon advice from a reptile rescue
coordinator who consulted with a veterinarian, placed the alligator in a shallow
freshwater bath for rehydration. The alligator moved around a bit and ingested some
Notes of the Southeastern Nat u ral ist, Issue 8/4, 2009
2009 Southeastern Naturalist Notes 747
water, but despite these efforts, died several hours after rescue. A necropsy was not
performed and the Texas Parks and Wildlife Department (TPWD) was contacted for
instructions as to disposition of the carcass.
Mr. Mike Wheelington of the TPWD notified the Louisiana Department of Wildlife
and Fisheries (LDWF) of the alligator finding, and the web tag imprinted with
“LDWF” and a six digit number identified it as a juvenile male (104 cm TL) that had
been released from a Louisiana alligator farm as part of the “head start” component
of the alligator egg ranching program (Elsey et al. 2001) in Johnson’s Bayou in southwest
Louisiana on 30 July 2008. We believe this American Alligator was swept away
from the release site by the massive storm surge of Hurricane Ike, and was displaced
(or rode on driftwood) along with other debris that washed ashore on Padre Island
National Seashore due to the counterclockwise rotation of Gulf waters caused by the
hurricane. To our knowledge, this straight-line distance of approximately 489 km
(Fig.1) is a record displacement for an American Alligator.
The location of the wetlands where the alligator was released, the rotation of
the storm, the storm’s path, along with the huge amounts of storm debris which also
washed up at the same location on PAIS make displacement by Hurricane Ike a very
plausible explanation for this finding. One report noted a four-mile stretch of this
beach produced enough debris to fill 2970 industrial-size trash bags; more than 96
km of the national seashore were littered by debris from storm-affected areas (Sherman
2008). Interestingly, shortly after preparing the initial draft of this manuscript,
we became aware of a newspaper article documenting the finding on this same beach
(PAIS) of a day planner and other personal items belonging to a woman whose home
in Johnson’s Bayou had washed away during Hurricane Ike (Carrillo 2008). This is
the same location from which the alligator originated.
Figure 1. Displacement of a juvenile American Alligator 489 km from coastal southwest Louisiana
where it was released on 30 July 2008 to Padre Island National Seashore. It was recovered
on 28 September 2008, presumably carried by storm surge from Hurricane Ike. The asterisk
indicates Galveston Island, where Hurricane Ike made landfall on 13 September 2008.
748 Southeastern Naturalist Notes Vol. 8, No. 4
It is possible humans moved the alligator to PAIS; however, much of the park is
accessible only by all terrain vehicle, making this unlikely. The physical condition
of the alligator (severely dehydrated suggesting exposure to full-strength seawater)
and timing of the alligator’s displacement with the occurrence of Hurricane Ike make
relocation by the hurricane a reasonable explanation for this long-distance displacement.
Also, alligators caught illegally and then released or abandoned are more
commonly found in urban settings, rather than the remote coastal situation and the
undeveloped barrier island described herein.
We have previously observed numerous cases of dispersal by farm-released
alligators (Elsey et al. 2001) and some cases of long-distance dispersal by wild alligators,
including one female alligator (initially 155 cm and 210 cm at recapture three
years later) that moved 90.17 km (Elsey et al. 2004). Although American Alligators
are quite resilient and can move long distances, we believe the distance from where
the alligator in this case was recovered in lower Texas from its release site in southwest
Louisiana is a case of extreme displacement by Hurricane Ike.
Acknowledgments. We thank Mr. Michael Allein of Corpus Christi Reptile Response
and Exotics Rescue for his efforts with the care of the displaced alligator.
Carrillo, R. 2008. Planner book fl oats 200 miles from J.B. The Cameron Parish Pilot. October
16, 2008. Vol. 52, No. 2. pg. 1.
Elsey, R.M. 2005. Unusual offshore occurrence of an American Alligator. Southeastern Naturalist.
Elsey, R.M., and N. Kinler. 2004. Louisiana’s alligator program: Adapting management as
populations recover and risk of unsustainable use decreases. Pp. 92–101, In Crocodiles.
Proceedings of the 17th Working Meeting of the Crocodile Specialist Group, IUCN–The
World Conservation Union, Gland, Switzerland and Cambridge, UK. 530 pp.
Elsey, R.M., L. McNease, and T. Joanen. 2001. Louisiana’s alligator ranching program: A
review and analysis of releases of captive-raised juveniles. Pp. 426–441, In G. Grigg, F.
Seebacher, and C.E. Franklin (Eds.). Crocodilian Biology and Evolution. Surrey Beatty and
Sons, Chipping Norton, New South Wales, Australia. 446 pp.
Elsey, R.M., V. Lance, and P.L. Trosclair III. 2004. (Abstract). Evidence for long-distance migration
by wild American Alligators. Pp. 415, In Crocodiles. Proceedings of the 17th Working
Meeting of the Crocodile Specialist Group, IUCN–The World Conservation Union,
Gland, Switzerland and Cambridge, UK. 530 pp.
Elsey, R.M., N. Kinler, V. Lance, and W.P. Moore III. 2006. Effects of Hurricanes Katrina and
Rita on alligators (Alligator mississippiensis) in Louisiana. Pp. 267–279, In Crocodiles.
Proceedings of the 18th Working Meeting of the Crocodile Specialist Group, IUCN–The
World Conservation Union, Gland, Switzerland and Cambridge UK. 404 pp.
Joanen, T., and L. McNease. 1987. The management of alligators in Louisiana, USA. Pp.
33–42, In G. J.W. Webb, S.C. Manolis, and P.J. Whitehead (Eds.). Wildlife Management:
Crocodiles and Alligators. Surrey Beatty and Sons. Chipping Norton, New South Wales,
Australia. 552 pp.
Lance, V.A., L.A. Morici, and R.M. Elsey. 2001. Physiology and endocrinology of stress in
crocodilians. Pp. 327–40, In G. Grigg, F. Seebacher, and C.E. Franklin (Eds.). Crocodilian
Biology and Evolution. Surrey Beatty and Sons, Chipping Norton, New South Wales,
Australia. 446 pp.
Lauren, D.J. 1985. The effect of chronic saline exposure on the electrolyte balance, nitrogen
metabolism, and corticosterone balance in the American Alligator, Alligator mississippiensis.
Comparative Biochemistry and Physiology. 81A:217–23.
Morici, L.A. 1996. Endocrine and physiological response to osmotic stress in the American
Alligator, Alligator mississippiensis. M.Sc. Thesis. Department of Biology, University of
San Diego, San Diego, CA. 145 pp.
2009 Southeastern Naturalist Notes 749
Sherman, C. 2008. Debris of life washes onto Texas shores. Associated Press. Baton Rouge
Morning Advocate, Friday October 3, 2008, p.11A.
1Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge 5476 Grand Chenier
Highway, Grand Chenier, LA 70643. 2US Department of the Interior, National Park Service,
Padre Island National Seashore, PO Box 181300, Corpus Christi, TX 78480. *Corresponding
author - email@example.com.