Schildkröten im Fokus
, Bergheim 7 (3) 2010: 10–25
Lithophagie bei Schildkröten
Lithophagy in Chelonians.
Very often keepers of tortoises observe that tortoises ingest stones or sand and frequently argue that they, like birds, need stones for
optimal digestion. On the other hand coproliths are sometimes the cause of death as revealed by necropsy. Therefore, the question of whether
tortoises need stones for their digestions needs some clarification. In addition very often keepers and veterinarians argue that the
hydrochloric acid production in the stomach dissolves limestone and contributes to the digestion of minerals. Here I provide an histological
overview by comparing the alimentary tract (and especially the stomach and proximal small intestine) of grain eating, gizzard bearing birds
such as doves with those of the tortoise Testudo hermanni
and the turtle Emys orbicularis
, as well as with the stomach of
omnivorous humans, insectivorous hedgehogs or herbivorous mammals such as roe deer and guinea pig. The histological and histochemical data
provide clear evidence that the digestion of the tortoise is not supported by stones as it is known for certain bird species. Furthermore
HCl producing parietal cells which are characteristic for the stomach of mammals as well as the characteristic Brunner glands of the
duodenum are lacking in European tortoises and turtles which indicates that tortoises and turtles do not form HCl within the stomach. In
addition I refer briefly to natural habitats of European tortoises in order to explain their adaptive behaviour to feed on gravel when they
suffer from calcium deficiency or when they are affected by parasites.
Alimentary tract, histology, histochemistry, glandular stomach, gizzard, intestine, parietal cells, Brunner gland, lithophagy, psammophagy,
coproliths, birds, Reptilia, Chelonia, Testudines, Testudinidae, Testudo graeca, Testudo hermanni
, Emydidae, Emys
, humans, hedgehog, deer, guinea pig.
Alter Kirchweg 11
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