METHODS
Ethics Statement. — The research was done under permission from the Wildlife Research and Training Institute Permit No: WRTI-0104-10-21 and approved by the National Commission for Science, Technology and Innovation (Licence No: NACOSTI/P/22/17049). The study was conducted according to standards for animal health and welfare as stipulated in the National Museums of Kenya ISO certified manual for animal care and humane handling of live animals. No animals were removed from their natural habitats nor their derivatives whatsoever collected.
Study Area. — The study was carried out between July 2020 and June 2022 in Wingemi area, Kitui county, Kenya between 00o - 01o South and 038o - 039o East at an elevation ranging from 510-574m above sea level. The ground here is undulating, generally sandy and has scattered rock outcrops and Kopjes (Kirkpatrick 1997; Malonza 2003) some of which have crevices suitable for Pancake tortoise habitation. The area experiences two rainy seasons: the short rainy season between November and December and long rainy season between March and May. The rains are erratic and thus this region experiences frequent droughts. Rivers and streams are seasonal usually existing as dry river beds. The residents often practice subsistence cultivation and pastoralism.
Combination of Group-level Scan Sampling and Ad Libitum sampling. — Observational sampling methods involving group-level scan sampling and ad libitum sampling as described by Van Belle (2017) were used to study the behavior of 39 Pancake tortoises inhabiting 12 crevices (designated as long-term ecological monitoring stations) in the study area from July 2020 to June 2022. Monitoring visits were made to the stations both during the dry and wet seasons and on each visit the number of tortoises present were recorded. All the activities observed of a given individual or the tortoise family during each visit were recorded. The stations were visited on a rotational basis, usually between 08:00hrs-18:00hrs. Occasional night visits to the crevices were also made to observe the activity of the tortoises at night.
Radio-tracking. — To gather data on movement patterns of the Pancake tortoise, 14 of the tortoises were fitted with R1-2B radio transmitters weighing 9g (Holohil Systems Ltd, Ontario, Canada) between July -December 2020 and their movement tracked using FCC ID: GZ383TTRX1000S radio receiver. Following guidelines by Goodlet et al. (1998), the transmitters were fitted on the front costal (pleural) scute using clear hardened epoxy resin with the transmitter tail positioned slightly facing sideways in females to avoid obstruction during mating. Such kind of transmitters have been successfully used in other chelonian studies without any harm to the animals, for instance the observation on the population ecology of the Three-toed Box Turtle (Rielde et al. 2017).
The first batch of seven tortoises was fitted with radio-transmitters on 26th June 2020. These included three adult male-female pairs and a small adult male that had been residing in the same crevice with a juvenile male. These were fitted with radio-transmitters and translocated in covered boxes from their original crevices and released in two of the crevices (all to the east) designated as long-term monitoring stations: one pair was released at station 1 and the other two pairs and the single male at station 2. The reason for the translocation was to bring the tortoises to accessible crevices for ease of monitoring their behavior. The average distance from the original crevices to the crevices of translocation was 1.37±0.21 km. After one of the translocated tortoises shed off the transmitter, it was collected and fitted to another resident of Station 2, henceforth acting as a control.
Unexpectedly, two of the radio-tracked tortoises started on what seemed to be a westbound homing journey, eventually reaching their respective home crevices, 2.1255km and 1.2798km away, respectively. This unique behavior prompted us to further experiment on the homing ability of the species. We thus collected the two already homed tortoises and released them at a different orientation farther west from their original home crevices to test if the behavior would recur. To increase the sample size, a resident male-female pair of station 4 and another resident male-female pair of station 6 were also collected, fitted with radio-transmitters and interchanged from their respective stations (crevices) on 3rd December 2020. The two stations are 0.523km (straight line displacement) apart, the former on the east and the latter to the west. Additionally, a tortoise pair (a juvenile male and an adult male) from station 11 was also collected, and relocated to Station 2, which is 0.6172km away to the west. All of these tortoises were followed closely to study their movement patterns and behavior.