Nota científica

PREDATION EVENT OF THE YUCATAN NEOTROPICAL

RATTLESNAKE CROTALUS TZABCAN (SQUAMATA: VIPERIDAE) ON A RODENT, IN SOUTHERN QUINTANA ROO, MEXICO

Evento de depredación de la víbora de cascabel yucateca Crotalus tzabcan

(Squamata: Viperidae) sobre un roedor, en el sur de Quintana Roo, México

José Rogelio Cedeño-Vázquez¹, Pablo M. Beutelspacher-García²and Rubén Alonso Carbajal-Márquez³*

¹El Colegio de la Frontera Sur Unidad Chetumal. Departamento de Sistemática y Ecología Acuática. Av. Centenario km 5.5, 77014 Chetumal, Quintana Roo, México. rcedenov@ecosur.mx, https://orcid.org/0000-0001-7763-902X ²Independent researcher. 16-A esquina con 31, Colonia Nueva Generación, 77500 Bacalar, Quintana Roo, México. beutelspacherpacher@gmail.com, https://orcid.org/0009-0002-7949-1561.

³Universidad Autónoma de Aguascalientes. Colección Zoológica, Departamento de Biología. Avenida Universidad 940, 20100 Aguascalientes, México.

*Corresponding author: ruben.carbajal@edu.uaa.mx, https://orcid.org/0000-0002-7407-0402.

[Recieved: March 06, 2025. Accepted: June 23, 2025]

ABSTRACT

The Yucatan neotropical rattlesnake (Crotalus tzabcan) is a crotalid endemic to the Yucatan Peninsula. Although it is widely distributed in this region, it is considered a highly elusive species, thus knowledge about its natural history is scarce, including observations on feeding ecology. Here, we report the first documented observation of a predation event of a wild C. tzabcan on a rat in a rural area in southern Quintana Roo, Mexico.

Keywords: anthropomorphized environment, Bacalar, Crotalinae, Quintana Roo, rodents, Yucatan Peninsula

RESUMEN

La víbora de cascabel yucateca (Crotalus tzabcan) es un crotálido endémico de la península de Yucatán. Aunque está ampliamente distribuida en esta región, se considera una especie muy escurridiza, por lo que el conocimiento sobre su historia natural es escaso, incluyendo observaciones sobre ecología alimenticia. Reportamos el primer evento de depredación de una C. tzabcan silvestre sobre una rata, en una zona rural en el sur de Quintana Roo, México.

Palabras clave: ambiente antropizado, Bacalar, Crotalinae, Quintana Roo, roedores, península de Yucatán

Documentation of predatory interaction events is essential to understand the interconnectivity of trophic systems and the underlying ecology of animal species involved in them; nonetheless, direct observations of them in the wild can be rare, particularly in elusive or secretive species (Sáez-Gómez et al., 2018 and references therein). The documentation of these observations in primary literature is, thus, even less likely. Here, we report the first observation of a predatory behavior event by a wild C. tzabcan on a rat in an area inhabited by people in southern Quintana Roo, Mexico.

The Tzabcan or Yucatan neotropical rattlesnake (Crotalus tzabcan) is a large (up to 1.818 mm in total length) crotalid endemic to the Yucatan Peninsula biotic province, where it mostly inhabits in open and dry habitats (Carbajal-Márquez et al., 2020a; Díaz-Gamboa et al., 2020; Heimes, 2016); areas of human habitation that apparently attract large numbers of rodents which in turn pull their predators from the forests. This venomous snake can exhibit diurnal, crepuscular, or nocturnal habits, depending on the climatic season. During the cold months of the dry season, it is generally found active during the daytime, whereas during the hot months of the rainy season its activity tends to be nocturnal. It is a highly elusive predator that is difficult to observe and follow in the field, specialized in preying predominantly on rodents and other small mammals (Carbajal-Márquez et al., 2020a, b).

On 15 January 2025 at 14:07 h during herpetofauna fieldwork, an adult female C. tzabcan (Fig. 1) was found preying on a medium-sized rodent (Fig. 2A). The observation took place in a secondary vegetation-grassland patch next to a banana plantation at Rancho Santa Lupita, located between Bacalar and Reforma, Municipality of Bacalar, Quintana Roo, Mexico (18.76901°N, 88.52260°W; WGS 84; 32 m elev.). The distress call of the rat upon being attacked by the snake led us to find the scene of the attack and allowed us to observe the event. We observed the predation event during which we took a video from a safe distance so as not to disturb the snake, allowing it to continue its normal feeding behavior. The prey was consumed headfirst (Fig. 2A, B) and consumption began while the prey was still alive, moving for over a minute as it was being ingested. The snake continued to swallow the prey slowly, for approximately eight minutes, until it was completely ingested. After that, the snake remained quiet at the scene. We then proceeded to carefully capture it with the help of a hook and a herpetological tong in order to determine a mass (with a 30 kg capacity electronic scale: 2.66 kg; previously contained in a blanket sack), length (with a measuring tape: snout-vent length = 1.35 m; total length = 1.47 m; previously contained in a transparent plastic tube), to determine sex by probing for the hemipenes (which were absent), and to photograph the individual for documentation. Finally, we relocated the snake to a natural vegetated area, located very close to the observation site.

Although we could not determine the prey´s taxonomic identity, judging by its size and appearance, it likely was a Toltec cotton rat (Sigmodon toltecus) or a Coues’s rice rat (Oryzomys couesi). Both rodent species have been previously recorded as common prey items of C. tzabcan (Carbajal-Márquez et al., 2020b). Our observation of C. tzabcan ingesting a rodent confirms that they exhibit diurnal activity during the dry cold months of the winter season of the Yucatan Peninsula, as well as the previously documented habit of year-round feeding (Carbajal-Márquez et al., 2020a, b).

Cedeño-Vásquez et al: Predation event of Crotalus tzabcan in Quintana Roo

Figure 1. Adult female Crotalus tzabcan photographed after preying on a rodent at Rancho Santa Lupita, Bacalar, Quintana Roo, Mexico.

Figure 2. Screenshots of a video showing the ingestion of a rodent by Crotalus tzabcan (A), initiating its consumption first by the rodent’s head (B).

ACKNOWLEDGMENTS

We want to thank Pablo Roberto Salazar Gómez, owner of Rancho Santa Lupita, for giving us access to his land, Gabriela Zacarías de León for editing the figures, and Chris Buttermore for the English review of the manuscript. To the General Directorate of Wildlife of SEMARNAT, for granting the scientific collection license (Oficio Nº SPARN/DGVS/10672/23, with extension of validity Oficio Nº SGPA7DGVS/05041/24) to Uri Omar García Vázquez, with an extension for P.M.B.-G. We thank the reviewers’ comments that resulted in the improvement of this manuscript. R.A.C.-M. thanks the Consejo Nacional de Humanidades, Ciencias y Tecnologías (CONAHCYT) and Universidad Autónoma de Aguascalientes (UAA) for providing a postdoctoral fellowship and institutional help and IUCN‘s Viper Specialist Group.

REFERENCES

Carbajal-Márquez, R. A., Cedeño-Vázquez, J. R., Martins, M. & Köhler, G. (2020a). Life history, activity pattern, and morphology of Crotalus tzabcan Klauber, 1952 (Serpentes: Viperidae). Herpetological Conservation and Biology, 15, 228–237.

Carbajal-Márquez, R. A., Cedeño-Vázquez, J. R., González-Solís, D. & Martins, M. (2020b). Diet and feeding ecology of Crotalus tzabcan (Serpentes: Viperidae). South American

Journal of Herpetology, 2020, 9–19. http://doi.org/10.2994/SAJH-D-17-00081.1

Díaz-Gamboa, L., May-Herrera, D., Gallardo-Torres, A., Cedeño-Vázquez, R., GonzálezSánchez, V., Chiappa-Carrara, X. & Yañes-Arenas, C. (2020). Catálogo de reptiles de la península de Yucatan. Universidad Nacional Autónoma de México (UNAM).

Heimes, P. (2016). Herpetofauna Mexicana Vol. 1 Snakes of Mexico. Edition Chimaira.

Sáez-Gómez, P., Palacios, S. & Camacho, C. (2018). Landscape change promotes the emergence of a rare predator-prey interaction. Food Webs, 15, e00078. http://doi.org/10.1016/j.fooweb.2018.e00078

Citation: Cedeño-Vázquez, J. R., Beutelspacher-García, P. M., & Carbajal-Márquez, R. A. (2025). Predation event of the Yucatan neotropical rattlesnake Crotalus tzabcan (Squamata: Viperidae) on a rodent, in southern Quintana Roo, Mexico. Novitates Caribaea, (26), 59–62. https://doi.org/10.33800/nc.vi26.378