Natural History of the Alamos Mud Turtle near Alamos, Sonora: Results of a Multiyear Mark–Recapture and Radio-Telemetry Study

In this study we report a multiyear mark–recapture study of 3 natural populations of the Alamos Mud Turtle (Kinosternon alamosae), one of the least-studied species in the family Kinosternidae in Mexico. We used hoop nets to capture turtles and documented their movement patterns and home range using radio-telemetry near the municipality of Alamos, Sonora. We characterized basic population parameters and estimated home range size with the Minimum Convex Polygon (MCP) and Kernel Density Estimator (KDE) techniques. From August 2019 to September 2023, we marked a total of 103 K. alamosae, most of which were adults (46 males, 40 females, and 17 subadults or immatures). Sex ratio was not biased. However, the study site experienced a drought between November 2019 and June 2021, which left the cattle tanks dry for up to 19 mo and interrupted our sampling efforts. The estimated population size of the 3 tanks was 109 turtles using a Log-Linear model for open populations, and 213 turtles considering a model for closed populations. Density and biomass values based on the open population model were 267 turtles/ha and 54.5 kg/ha, while the closed population model produced estimates of 520 turtles/ha and 106.3 kg/ha. Females were wider and had a taller carapace than males. We tracked 10 K. alamosae for 116 to 1076 days, with an average of 533 days per turtle during 3 estivation periods (623, 237, and 85 days, respectively). Home range size (MCP) ranged from 1 to 55 ha, with a mean (± SD) of 13.25 ± 18.3 ha (n = 8) and did not differ by sex. In turn, KDE home size ranged from 8.1 to 270.8 ha, with a mean (± SD) of 64.03 ± 87.6 ha (n = 8), and likewise showed no sex-related differences. Individuals in this population tended to bury under woody debris to aestivate in 86 out of 161 records, traveling up to 1.3 km from the water body to estivate. Our findings highlight the unique ability for K. alamosae to find appropriate microhabitats and spend significant periods of time outside of the water, suggesting that the species may be exceptional at withstanding extended droughts.