Geology topics

Grant S. McCargar

Publications and source records attributed to Grant S. McCargar.

2 recordsLinked to original sources

USGS2026

Arboreal habitat use by invasive Burmese Pythons in southern Florida

Understanding habitat use and behavior is critical to developing effective management strategies for a species. Burmese Pythons ( Python bivittatus ) are large-bodied snakes native to southeastern Asia that have become prolific invaders throughout the Greater Everglades Ecosystem in southern Florida, USA. We radio-tracked 188 adult and 168 juvenile Burmese Pythons to investigate arboreal microhabitat use and quantify the likelihood of observing Burmese Pythons in arboreal habitat. We observed adult pythons basking, resting, aggregating with other pythons, or brooding eggs in arboreal habitat, whereas we observed juvenile pythons resting, basking, or moving between tree limbs. Both adult and juvenile pythons were more likely to use arboreal habitat during the cooler months of December and January in southern Florida's dry season. A higher percentage of individual juvenile pythons than adult pythons used arboreal habitat, and the probability that a python occupied arboreal habitat decreased as its weight increased. Brazilian peppertrees ( Schinus terebinthifolia ) and live oaks ( Quercus virginiana ) supported heavier pythons. Information on the seasonal use of arboreal habitats by Burmese Pythons could improve the effectiveness of removal efforts by management agencies and enhance our understanding of the threats these snakes pose to vulnerable species, particularly arboreal-nesting birds.

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USGS2025

Cold-induced vomiting of a white-tailed deer (Odocoileus virginianus) by an invasive Burmese python (Python bivitattus) in Big Cypress National Preserve, Florida, USA

The Burmese python ( Python bivittatus ) is native to Southeast Asia and has an established invasive population throughout South Florida. As part of the effort to understand invasive python biology and potential impacts to the native ecosystem, we have been using radio-telemetry to investigate feeding rates of adult female pythons. The body size and gape of adult Burmese pythons enable them to consume large native prey items including, but not limited to, white-tailed deer ( Odocoileus virginianus ). As an ectothermic species, Burmese pythons' physiological processes, including digestion, are temperature dependent, which may limit their potential invasive range. The low temperature threshold for python digestion is thought to be 20°C within a laboratory setting. Here, we detail an observation of a radio-telemetered female Burmese python that ingested an adult white-tailed deer, retained the deer within the digestive tract for 10 days, and then vomited the deer coinciding with a drop in air temperature as low as 9.4°C. The python survived the vomiting and was alive at the time of publication. To our knowledge, this is the first observation of a free-ranging Burmese python vomiting a deer within the invasive range without direct disturbance from humans at the time of vomiting. This observation provides additional evidence regarding the limits of thermal tolerance, digestion, and feeding habits of invasive Burmese pythons.

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