Reproductive ecology of the critically endangered pancake tortoise

• Published in: Wildlife biology 2024-09, Vol.2024 (5), p.1
• Main Authors: Ngwava, Jacob Mueti, Xiao, Fanrong, Malonza, Patrick K, Bwong, Beryl A, Shi, Hai-Tao
• Format: Article
• Language: English
• Subjects: Ecological research; Endangered species; Environmental aspects; Natural history; Sexual behavior
• ISSN: 0909-6396
• DOI: 10.1002/wlb3.01181

Reproduction of the pancake tortoise in the wild has remained poorly known over the decades. This study fills the knowledge gap by investigating the reproductive ecology of the species in its natural habitats in Kenya. Data were collected using the time-constrained search-and-seize method, group-level scan sampling, radio tracking, and camera-trapping. Our observations revealed a total of 19 mating events that occurred between December and April, predominantly during the rainy seasons. Mating duration averaged 15.2 [+ or -] 2.4 min. Male--male aggression was observed during the mating season, with the dominant male keeping off all other males and mating with the resident females. Nest preparation events occurred between April and June. Nine nesting events were recorded, but in only five of them was an egg deposited. The nests were dug in loose soil, appeared almost circular, and measured 8.4 [+ or -] 0.9 cm wide and 7.0 [+ or -] 0.1 cm deep (n = 7). The average clutch size was one egg. The eggs were white, hard-shelled, oval, and elongated measuring 4.4 [+ or -] 0.4 cm long, 2.7 [+ or -] 0.04 cm wide and weighed 17 [+ or -] 0.6 g (n = 3). Incubation period lasted 177 [+ or -] 5.7 days (n = 2), and hatching coincided with the onset of the short rainy season in November, aligned with the availability of abundant food for the tortoises. The hatchlings were minimally wider than long, having an average straight carapace length of 4.5 [+ or -] 0.6 cm, an average width of 4.5 [+ or -] 0.4 cm, and on average weighed 14.7 [+ or -] 3.7g, (n = 9). They remained near the nest site for 4-5 days before relocating to tiny rock crevices away from the adult tortoise crevices. Egg and hatchling predation was high, with four of the total of six eggs, observed after they were laid, being destroyed. Three juveniles, out of nine, were also eaten by predators. These findings contribute useful information for the formulation of effective conservation and management strategies for this critically endangered species.