Schildkröten im Fokus
, Bergheim 9 (2) 2012: 3–26
Hamiltons Gesetz, Selektion nach dem Verwandtschaftsgrad oder gar altruistisches Verhalten bei Spaltenschildkröten, Malacochersus tornieri? – Eine Beobachtung zum Sozialverhalten
Text und Bilder von Hans-Jürgen Bidmon, Düsseldorf
Hamilton’s rule, kin selection or even altruism in the pancake tortoise, Malacochersus tornieri? – An observation on social behaviour
Text and photos Hans-Jürgen Bidmon, Düsseldorf, Germany
The captive raising and maintenance of a young breeding pair of the pancake tortoise, Malacochersus tornieri
is described. The 2
individuals were brought together as sub-adults. Since 2007 this pair reproduced continuously during the indoor season with one exception
during which the eggs had been already deposited in the outdoor enclosure where they are kept during summer. Beginning with her first
indoor nesting season the female buried the eggs in the ground within the artificial hiding shelter (crevice) of the male where they
stayed until hatching. The male always leaves his favoured hiding place during the time period one of the eggs hatches but returns
immediately after the hatchling is free. In one occasion the female deposited an unburied egg in the same place which resulted in complete
abandoning of the male’s preferred shelter for the whole period of incubation. During that period the male stayed in the only other free
artificial crevice which is usually not preferred by both parent tortoises. Both adults are not aggressive against their hatchlings. That
unexpected behaviour of the male (father) is discussed in respect to Hamilton’s rule in terms of kin selection–and or altruism–theory.
This observation made during captive breeding in combination with what is known about their isolated and restricted lifestyle (ecological
niches) in the wild provides an indication that Malacochersus tornieri
represents an excellent model reptile for studying the
evolution of more complex social behaviour in response to crevice availability and predation pressure. That last suggestion is discussed
in greater detail and on the basis of the available literature arguing also for more observations and input from institutional and other
private breeders of this species.
Reptilia, Testudines, Testudinidae, Malacochersus tornieri
, pancake tortoise, kin selection, altruism, cooperation,
Hamilton’s rule, evolution biology, behavioural biology.
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