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.