The Lazy Naturalist - Sarasota, Florida

Exploring Nature in Sarasota, South Central Florida, and Beyond

Florida softshell turtle (Apalone ferox)

by Artie Visual, Categories: Reptiles & Amphibians Tags:


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This unique and often misunderstood reptile, with its distinctive leathery shell and snorkel-like snout, is an emblem of the freshwater ecosystems of Florida. From its peculiar physical traits to its fascinating behavior and crucial ecological role, the Florida Softshell Turtle is a testament to nature’s creativity and adaptability.

A Unique Appearance

The Florida Softshell Turtle is easily distinguishable from other turtles by its soft, leathery carapace and streamlined shape. Unlike the hard, bony shells of most turtles, the softshell’s carapace is flexible and smooth, with a rubbery texture that gives the turtle a unique appearance and the flexibility needed for an aquatic lifestyle. This shell, ranging in color from olive to dark brown with blotches and spots, allows the turtle to blend seamlessly with the muddy bottoms of ponds, lakes, and rivers.

The most striking feature of the Florida Softshell Turtle is its elongated, snorkel-like snout. This adaptation enables the turtle to breathe while submerged, with only the tip of its snout breaking the water’s surface. Coupled with its webbed feet and powerful limbs, the turtle is an adept swimmer, capable of quick bursts of speed both in water and on land.

Habitat and Distribution

The Florida Softshell Turtle is found primarily in the southeastern United States, with Florida being its stronghold. It thrives in a variety of freshwater habitats, including ponds, lakes, rivers, marshes, and even man-made canals. This adaptability to different water bodies makes it a common sight in Florida’s diverse aquatic environments.

These turtles prefer habitats with soft, sandy, or muddy bottoms where they can easily bury themselves to avoid predators or ambush prey. They are often seen basking on the banks of water bodies or floating near the surface, with only their heads visible, taking advantage of the warm Florida sun.

Behavior and Diet

The Florida Softshell Turtle is both a predator and scavenger, playing a significant role in maintaining the balance of its ecosystem. Its diet is diverse and opportunistic, including fish, insects, crustaceans, amphibians, and even small birds and mammals. The turtle uses its long neck and sharp, beak-like jaws to snatch prey with surprising speed and precision.

Despite their somewhat menacing diet, these turtles are generally shy and prefer to avoid human interaction. When threatened, they can be quite aggressive, using their powerful limbs and sharp jaws to defend themselves. However, their primary defense mechanism is their ability to quickly retreat into the water and bury themselves in the substrate, where they can remain hidden from predators.

Reproduction and Life Cycle

The breeding season for the Florida Softshell Turtle typically occurs from March to July, with females laying multiple clutches of eggs throughout the season. Females leave the water to find suitable nesting sites, often sandy banks or areas with loose soil, where they dig shallow nests and deposit between 10 to 30 eggs per clutch.

The eggs incubate for about 60 to 90 days, with the temperature of the nest influencing the sex of the hatchlings. Warmer temperatures generally produce females, while cooler temperatures produce males. Upon hatching, the young turtles make their way to the water, where they begin their lives relatively independent from their mothers.

Florida Softshell Turtles have a long lifespan, often living 20 to 30 years in the wild. Their longevity, coupled with their high reproductive output, helps maintain their populations despite the various threats they face.

Ecological Importance

The Florida Softshell Turtle is an integral part of Florida’s freshwater ecosystems. As both predator and scavenger, it helps control populations of fish, insects, and other aquatic organisms, contributing to the overall health and balance of its habitat. By preying on weak or diseased animals, the turtle helps maintain healthy populations of its prey species, acting as a natural regulator.

Additionally, the turtle’s nesting behavior contributes to the aeration and mixing of soil along the banks of water bodies, promoting plant growth and maintaining the structure of the habitat. The presence of Florida Softshell Turtles can be an indicator of a healthy, well-functioning ecosystem, as they require clean water and suitable habitat conditions to thrive.

Historical and Cultural Significance

The Florida Softshell Turtle has long been a part of the natural and cultural landscape of the southeastern United States. Indigenous peoples, including the Seminole and Miccosukee tribes, were well-acquainted with these turtles and sometimes included them in their diets. The turtles were valued for their meat, which was considered a delicacy.

In modern times, the Florida Softshell Turtle has gained recognition among herpetologists and wildlife enthusiasts for its unique characteristics and important ecological role. However, it has also been subject to exploitation, particularly for its meat and the pet trade, which has led to concerns about overharvesting and population declines.

Conservation and Challenges

Despite their adaptability and resilience, Florida Softshell Turtles face several significant challenges. Habitat loss and degradation due to urban development, pollution, and water management practices are primary threats. The alteration of natural water bodies and the destruction of nesting sites can have severe impacts on their populations.

Road mortality is another major issue, as turtles often cross roads in search of nesting sites or new habitats, only to be struck by vehicles. Additionally, the illegal collection of turtles for the pet trade and consumption poses a threat to wild populations.

Climate change also presents a looming challenge, as alterations in temperature and precipitation patterns can affect the availability of suitable habitats and the timing of reproductive cycles. Conservation efforts for the Florida Softshell Turtle include habitat protection and restoration, public education and awareness campaigns, and legal protections to regulate collection and trade.

A Personal Encounter

One of my most memorable encounters with a Florida Softshell Turtle occurred during a kayak trip along the tranquil waters of the Myakka River. The sun was beginning to set, casting a golden glow over the river, when I noticed a large, dark shape moving slowly along the sandy riverbank.

As I paddled closer, I realized it was a female Florida Softshell Turtle, likely searching for a nesting site. Her movements were deliberate and unhurried, her long neck craning as she surveyed the area. I watched in silent awe as she began to dig a nest with her powerful hind legs, creating a shallow depression in the soft sand.

The encounter was a poignant reminder of the delicate balance of nature and the critical role that even the most unassuming creatures play in maintaining the health of our ecosystems. Witnessing the turtle’s nesting behavior firsthand was a humbling experience, one that deepened my appreciation for the resilience and adaptability of these remarkable reptiles.

Conclusion

The Florida Softshell Turtle is more than just an unusual reptile; it is a vital component of Florida’s freshwater ecosystems. Its distinctive appearance, fascinating behavior, and important ecological role make it a captivating subject for naturalists and wildlife enthusiasts alike. From controlling populations of aquatic organisms to contributing to the health and balance of their habitats, these turtles are indispensable to the ecosystems they inhabit.

As we continue to face the challenges of habitat loss, climate change, and other environmental pressures, it is crucial to recognize and protect the valuable contributions of the Florida Softshell Turtle. By preserving their natural habitats and supporting conservation efforts, we can ensure that future generations will have the opportunity to marvel at these remarkable creatures.

So, the next time you find yourself exploring the waterways and wetlands of Florida, take a moment to appreciate the unique Florida Softshell Turtle. Whether you’re admiring its streamlined shape, observing its nesting behavior, or simply enjoying the knowledge that it is helping to keep the ecosystem in balance, you are witnessing a living testament to the beauty and complexity of the natural world. In doing so, you honor not only the turtle itself but also the intricate web of life that it supports and the timeless connection we share with nature.

Florida softshell turtle

The Florida softshell turtle (Apalone ferox) is a species of turtle in the family Trionychidae. The species is native to the Southeastern United States.[4][5]

Geographic range

The Florida softshell turtle is found primarily in the state of Florida, but it also ranges to southern sections of Alabama, Georgia, and South Carolina.[6] It is the only species of softshell turtle whose range spans the entire Florida peninsula.[7] Of the three species in the genus Apalone, the Florida softshell turtle occupies the smallest geographic range.

Habitat use

The Florida softshell turtle is a widespread species and occupies almost every freshwater habitat, even tolerating some brackish environments; however, it is not often found in water with strong currents, preferring habitats with slow-moving or still water. These different habitats include swamps, lakes, marshes, wet prairies, small rivers, creeks, and even ponds formed in man-made ditches or sinkholes.[8][9][10][11]

Description

Juvenile coloration in Florida softshell turtle (A ferox)

The Florida softshell turtle is a large turtle with a flattened, pancake-like body, a long neck, an elongated head with a long snorkel-like nose, and large webbed feet, each with three claws. While most turtles have hard shells composed of scutes, the Florida softshell turtle has a cartilaginous carapace covered in leathery skin. Ranging from olive green to dark brown, it has the darkest coloration of all the softshell species that inhabit Florida (other species include Apalone mutica calvata and Apalone spinifera aspera). It is also characterized by a white or cream-colored underside.[12][7] This color pattern is known as countershading and is a form of camouflage to conceal turtles from potential predators.[13]

It is the largest species of softshell turtle found in Florida and all of North America, ranging from 15 to 76 cm (5.9 to 29.9 in) in straight-line carapace length.[12] The Florida softshell turtle also exhibits significant sexual size dimorphism. Adult females are often 3-5 times larger than males. Males have a carapace length and body weight averaging about 35 cm (14 in) and 2.68 kg (5.9 lb) respectively. Nesting adult females were found to average 6.65 kg (14.7 lb) in weight and measure 40.1 cm (15.8 in) in carapace length, with the record weight documented at 43.6 kg (96 lb).[14][4] However, males tend to have longer tails than their female counterparts (3 cm longer than a female of the same size). Hatchlings have a lighter carapace with yellow and orange markings and a carapacial rim. Stripes in the same color are also found on the face and neck. The plastron of hatchlings is generally dark in color. As the turtle ages, these colors fade and are lost, resulting in the dark-brown coloration characteristic of adults.[12][7]

Behavior

The Florida softshell turtle is almost entirely aquatic, emerging from the water only to bask or to lay eggs.[12] In the water, it prefers to bury itself in the sandy/muddy substrate. Like all softshells, it is very fast-moving in water and on land.[12] While this species is omnivorous, its diet consists largely of meat, consuming mainly fish, insects, crustaceans, frogs and mollusks. It may also scavenge.[1]

Reproduction

Males

The reproductive cycle of male Florida softshell turtles follows a postnuptial pattern, with a cycle of spring mating followed by spermatogenesis in the fall. The male will produce sperm during the fall and store that sperm in the epididymides through the winter. This stored sperm can then be utilized for copulation during the following spring mating season. Evidence suggests that they undergo spermatogenesis every year. Males of this species reach sexual maturity at small sizes (below 0.7 kg), allowing them to begin reproducing quickly following birth. This implies that some males may be able to reproduce as young as two years of age.[14]

Females

While males consistently reach sexual maturity at small sizes, that size is larger and more variable in females. Some may reach maturity at a plastron length of 24 cm, and others may not mature until they reach a length closer to 30 cm. The onset of sexual maturity will occur anywhere from 5 – 8 years of age. The female nesting season can range anywhere from early April to early August, and incubation lasts an average of 60 – 90 days. In a study examining female reproduction, almost 10% of the females examined in a single breeding season showed signs of inactive ovaries, implying that, unlike males, females may not possess the ability to reproduce every year. Florida softshell females have the ability to produce an average of 4 – 5 egg clutches in a single breeding season, potentially producing a new clutch every three weeks. Florida softshell turtles have one of the highest annual egg production rates of any reptile. The study previously mentioned showed an average of over 20 eggs per clutch, with the largest clutch containing 38 eggs.[7][4]

Ecology

With a primarily carnivorous diet, adult Florida softshell turtles function as major predators in their aquatic ecosystems. Sitting high on the trophic scale, they generally function as secondary or tertiary consumers.[15] However, alligators have been known to prey on the adults of the Florida softshell turtle, and raptors may take juveniles. Nest predators include the fish crow, foxes, raccoons, skunks, and river otters.[1][16]

Preyed on by an American alligator

Utilization of American alligator nests

At various lakes across the state of Florida (Okeechobee, Apopka, Griffin, and Jesup) scientists have observed Florida softshell females, as well as other turtle species (Pseudemys nelsoni, Kinosternon sp., and Sternotherus odoratus) laying their eggs in American alligator (Alligator mississippiensis) nests during the summer months. While the turtles may utilize vacant nests more often, they have also been known to lay eggs in occupied alligator nests. They use these nests more often in areas with limited nesting habitats and/or during years with heavier precipitation when high water levels and flooding further reduce the number of suitable nesting sites.[17]

Despite the Florida softshell's use of alligator nests, studies have shown the highest abundance of Florida softshell turtles to persist in lakes with little to no alligators as well as high primary productivity, suggesting a combination of top-down and bottom-up influences on Florida softshell turtle populations.[18]

Anthropogenic threats

The Florida softshell turtle is common throughout Florida and other parts of its range. However, wild populations are subject to various threats at the hands of humans. Some of these threats include commercial harvesting for meat, harvesting for the pet trade, and roadway mortalities.[19][20]

Diet

The Florida softshell turtle is carnivorous with its main diet consisting of small snails and fish. It also preys upon amphibians, insects, mollusks, and some waterfowl. The Florida softshell turtle will hunt, chase, and scavenge for prey.[5]

References

  1. ^ a b c van Dijk, P.P. (2011). Apalone ferox. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. Downloaded on 21 July 2013.
  2. ^ U.S. Geological Survey (2017). "Florida Softshell (Apalone ferox) rFLSOx_CONUS_2001v1 Range Map". Gap Analysis Project. doi:10.5066/F78051R8.
  3. ^ Fritz, U.; Havaš, P. (2007). "Checklist of Chelonians of the World" (PDF). Vertebrate Zoology. 57 (2): 305–306. doi:10.3897/vz.57.e30895. ISSN 1864-5755. S2CID 87809001. Archived from the original (PDF) on 1 May 2011. Retrieved 29 May 2012.
  4. ^ a b c Iverson, J.B.; Moler, P.E. (1997). "The female reproductive cycle of the Florida softshell turtle (Apalone ferox)". Journal of Herpetology 31 (3): 399–409.
  5. ^ a b Rafinesque, Constantine S. "12. Description of two new genera of Soft Shell Turtles of North America." Atlantic Journal, and Friend of Knowledge. In Eight Numbers. Containing About 160 Original Articles and Tracts on Natural and Historical Sciences, the Description of About 150 New Plants, and 100 New Animals or Fossils. Many Vocabularies of Languages, Historical and Geological Facts, &c.(1832-1833) 1.2 (1832): 64.
  6. ^ Apalone ferox (Schneider, 1783). Archived 8 August 2009 at the Wayback Machine USGS.
  7. ^ a b c d Meylan, P.A.; Moler, P.E. (2006). "Apalone ferox – Florida Softshell Turtle." pp. 160–168. In: P.A. Meylan, P.A. (editor) (2006). Biology and Conservation of Florida Turtles. Lunenburg, Massachusetts: Chelonian Research Foundation.
  8. ^ Duellman W.E.; Schwartz, A. (1958). "Amphibians and Reptiles of Southern Florida". Bulletin of the Florida State Museum, Biological Sciences 3: 181–324.
  9. ^ "A contribution to the herpetology of Florida by Archie Fairly Carr, Jr". ufdc.ufl.edu. Retrieved 12 November 2018.
  10. ^ Webb, R.G. (1962). "North American Recent soft-shelled turtles (Family Trionychidae)". Publications of the Museum of Natural History, University of Kansas 13: 429–611.
  11. ^ Neill, W.T. (1958). "The occurrence of amphibians and reptiles in saltwater areas, and a bibliography". Bulletin of Marine Science, Gulf and Caribbean 8: 1–97.
  12. ^ a b c d e Apalone. www.tortoise.org
  13. ^ "Heron tries to swallow turtle for dinner". The Daily Telegraph. 18 December 2009.
  14. ^ a b Meylan, P.A.; Schuler, R.; Moler, P. (2002). "Spermatogenic cycle of the Florida softshell turtle, Apalone ferox ". Copeia 2002 (3): 779–786.
  15. ^ Aresco, M.J.; James, F.C. (2005). "Ecological relationships of turtles in northern Florida lakes: a study of omnivory and the structure of a lake food web". Final report. Florida Fish and Wildlife Conservation Commission, Tallahassee, Florida, USA.
  16. ^ Stacy, Brian A.; Wolf, Dan A.; Wellehan, James F.X. Jr. (2014). "Large-scale Predation by River Otters (Lontra canadensis) on Florida Cooter (Pseudemys floridana) and Florida Softshell Turtles (Apalone ferox)". Journal of Wildlife Diseases. 50 (4): 906–910. doi:10.7589/2013-10-271. ISSN 0090-3558. PMID 25098299. S2CID 40726994.
  17. ^ Enge, Kevin M.; Percival, H. Franklin; Rice, Kenneth G.; Jennings, Michael L.; Masson, Gregory R.; Woodward, Allan R. (2000). "Summer Nesting of Turtles in Alligator Nests in Florida". Journal of Herpetology. 34 (4): 497–503. doi:10.2307/1565262. JSTOR 1565262.
  18. ^ Aresco, M. J. (2009). Environmental correlates of the abundances of three species of freshwater turtles in lakes of northern Florida. Copeia, 2009 (3), 545–555.
  19. ^ Enge, K.M. (1993). "Herptile use and trade in Florida". Tallahassee, Florida: Florida Game and Fresh Water Fish Commission. Nongame Wildlife Program Final Performance Report. 102 pp.
  20. ^ Aresco, M.J. (2005). "Mitigation measures to reduce highway mortality of turtles and other herpetofauna at a north Florida lake". Journal of Wildlife Management, 69 (2): 549–560.

Further reading

  • Behler, J.L.; King, F.W. (1979). The Audubon Society Field Guide to North AmericanReptiles and Amphibians. New York: Alfred A. Knopf. 743 pp. ISBN 0-394-50824-6. (Trionyx ferox, pp. 483–484 + Plates 272, 273).
  • Boulenger, G.A. (1889). Catalogue of the Chelonians, Rhynchocephalians, and Crocodiles in the British Museum (Natural History). New Edition. London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). x + 311 pp. + Plates I–III. (Trionyx ferox, p. 259).
  • Conant, R. (1975). A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition. Boston: Houghton Mifflin. xviii + 429 pp. + Plates 1–48. ISBN 0-395-19979-4 (hardcover), ISBN 0-395-19977-8 (paperback). (Trionyx ferox, p. 81 + Plates 6, 12 + Map 35).
  • Schneider, J.G. (1783). Allgemeine Naturgeschichte der Schildkröten, nebst einem systematischen Verzeichnisse der einzelnen Arten und zwey Kupfern ". Leipzig: J.G. Müller. xlviii + 364 pp. + corrigenda. (Testudo ferox, new species, pp. 330–334). (in German and Latin).
  • Smith, H.M.; Brodie, E.D. Jr. (1982). Reptiles of North America: A Guide to Field Identification. New York: Golden Press. 240 pp. ISBN 0-307-47009-1 (hardcover), ISBN 0-307-13666-3 (paperback). (Trionyx ferox, pp. 32–33).
  • Stejneger, L.; Barbour, T. (1917). A Checklist of North American Amphibians and Reptiles. Cambridge, Massachusetts: Harvard University Press. 125 pp. (Amyda ferox, p. 124).
source: https://en.wikipedia.org/wiki/Florida_softshell_turtle

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