Date of Graduation

Spring 2025

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Ligon Day

Abstract

The Northern Giant Musk Turtle (Staurotypus triporcatus), a near-threatened species native to southern Mexico, Guatemala, Belize, and western Honduras, faces multiple environmental challenges, yet its activity patterns, movement patterns, and reproductive biology remain poorly understood. This thesis investigates both seasonal activity and reproductive cycles of female S. triporcatus in Belize. To assess diel and seasonal activity, I tracked 12 female turtles and collected data using activity loggers. I also collected movement data through radio-telemetry and acoustic tracking methods. Results indicated that the species is primarily nocturnal, with increased activity during the wet season, particularly during flooding events. Turtles moved significantly more during flooding, traveling nearly twice the daily distance compared to the dry season. Activity was influenced by temperature and depth, though seasonal depth use did not correlate with changes in activity levels. On the reproductive front, I used ultrasound imaging and radiographs to monitor cumulus-oocyte complex development and clutch characteristics in relation to the distinct wet and dry seasons of Belize. Vitellogenesis began in the wet season, and gravid females were first observed in September. Clutch size ranged from 4 to 11 eggs, with a positive correlation between egg size and clutch number. This research contributes valuable insights into the seasonal behavior and reproductive patterns of S. triporcatus, providing information for conservation strategies for this vulnerable species.

Keywords

: Staurotypus triporcatus, activity, accelerometer, movement, flood, diel, estivation, reproductive investment, oocyte, reproductive cycle

Subject Categories

Behavior and Ethology | Terrestrial and Aquatic Ecology

Copyright

© Larissa Sage Saarel

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