The guys return to Everglades National Park, again looking for a predator that Daniel wants to get too close to: the American Crocodile (Crocodylus acutus). Listen in as Daniel shares some research, busts croc-related myths, and Steve probably gets a little too excited about how crocs deal with salt water. Bill doesn’t have much to say, but he’s there, too. Enjoy!
This episode was recorded on January 7, 2025 on the Bear Lake Trail in Everglades National Park. The last bit where the guys find the croc was also recorded in the Park, at the Flamingo Marina.
Episode Notes and Links
As promised during the episode, Steve is looking into how crocs process and excrete excess salt. As soon as he gets to the bottom of it, we’ll share it here.
In the meantime, here’s what Bill found when he asked DeepSeek: Crocodiles, like many other marine and estuarine reptiles, have specialized salt glands to help them excrete excess salt from their bodies. These glands, known as salt glands or lingual glands (located on their tongues), actively transport salt ions (primarily sodium and chloride) from their bloodstream into the gland ducts. The salt is then excreted as a concentrated saline solution, which is expelled from the body.
Crocodiles do not chemically change the salt (sodium chloride) into something else. Instead, they filter and concentrate it, allowing them to maintain proper electrolyte balance in their bodies, especially when living in saltwater environments. This process is crucial for osmoregulation, as it prevents dehydration and helps them survive in both freshwater and saltwater habitats.
In summary, crocodiles excrete salt in its original form (sodium chloride) but in a highly concentrated solution, rather than transforming it into a different substance.
The crocodile featured above is the large male seen in the episode.
This photo is zoomed in on his lower jaw to make the many integumentary sensory organs (ISO’s) visible. Some of them are circled.
Alligator headshot
Crocodile headshot
The above photos show the difference in the jawline between alligators and crocodiles. The lower jaw’s teeth of members of the Alligator family (Alligatoridae) fit into pockets in the upper jaw, leaving only the top jaw’s teeth visible. The lower jaw’s teeth of members of the Crocodile family (Crocodylidae) fit into grooves on the outside of the upper jaw, leaving an interlocking appearance. As you can see from the photos, only the teeth on the top jaw are visible on the American Alligator, while you can see the interlocking top and bottom jaw teeth on the American Crocodile. The fourth bottom tooth on the American Crocodile is especially conspicuous.
The Atala butterfly (Eumaeus atala) and its larvae
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Works Cited
Admin, CrocAttack. “Database.” CrocAttack, CrocAttack, 17 July 2023, crocattack.org/database/.
Balaguera-Reina, S. A., M. Venegas-Anaya, V. Beltrán-López, A. Cristancho, and L. D. Densmore III 2018. Food habits and ontogenetic dietary partitioning of American crocodiles in a tropical Pacific Island in Central America. Ecosphere 9(9):e02393. 10.1002/ecs2.2393
Briggs-Gonzalez VS, Basille M, Cherkiss MS, Mazzotti FJ. American crocodiles (Crocodylus acutus) as restoration bioindicators in the Florida Everglades. PLoS One. 2021 May 19;16(5):e0250510. doi: https://pubmed.ncbi.nlm.nih.gov/34010342/
Grigg, Gordon C., et al. Biology and Evolution of Crocodylians. Comstock Publishing Associates, a Division of Cornell University Press ; CSIRO Publishing, 2015.
Mazzotti Frank J. , Balaguera-Reina Sergio A. , Brandt Laura A. , Briggs-González Venetia , Cherkiss Mike , Farris Seth , Godahewa Avishka 2022. Natural and Anthropogenic Factors Influencing Nesting Ecology of the American Crocodile in Florida, United States. Frontiers in Ecology and Evolution Vol. 10. https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2022.904576 ISSN=2296-701X
Mazzotti, F.J. The American Crocodile in Florida Bay. Estuaries 22, 552–561 (1999). https://doi.org/10.2307/1353217
Mazzoti, Frank. “American Crocodiles (Crocodylus Acutus) in Florida.” Myfwc.Com, University of Florida IFAS Extension, myfwc.com/media/1847/americancrocodilesinfl.pdf. Accessed Dec. 2024.
Villegas, Alejandro, & Schmitter-Soto, Juan Jacobo. (2008). Feeding habits of the American crocodile, Crocodylus acutus (Cuvier, 1807) (Reptilia: Crocodylidae) in the southern coast of Quintana Roo, Mexico. Acta zoológica mexicana, 24(3), 117-124. Recuperado en 30 de enero de 2025, de http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0065-17372008000300008&lng=es&tlng=en.
Photo Credit
All photos by The Field Guides except the Atala butterfly by https://ansg.org/caterpillars/