Island dwarfing

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The island gray fox native to the Channel Islands of California as an example of island dwarfing
Fossil skull of Europasaurus holgeri compared to a skull of the related dinosaur Giraffatitan

Island dwarfing is an evolutionary biological phenomenon in which the body size of animal species that live on an island without predators or human interference decreases significantly over generations (" dwarfed ").

The Canadian biologist J. Bristol Foster (* 1932) carried out initial research on island dwarfing . For him, the adaptation mechanisms in the event of overpopulation are the decisive factor as to whether a species tends to dwarf or to island gigantism .

Examples of island dwarfing include:

The tendency towards island dwelling can also be seen in raccoons, rabbits, pigs and deer. With a few exceptions, snakes also tend to dwarf islands. Small rodents on islands, on the other hand, tend to be island gigantism. H. Island forms of the animal order tend to develop significantly larger body shapes than on the mainland. The tendency towards gigantic growth can also be observed in iguanas , geckos , skinks and monitor lizards such as the Komodo dragon .

On the Dodecanese island of Tilos , excavations in the Charkadio Cave have uncovered the bones of a dwarf elephant species showing sexual dimorphism . The most recent 14 C date from the fossil-bearing layer (4390 ± 600 BP uncal) dates between 4340 and 1520 BC. Near. Tilos' pygmy elephant ( Elephas falconeri BUSK ) may not have become extinct until the Bronze Age . Other Neolithic dates come from other Mediterranean islands.

See also


  • Fr. Bachmayer, Nikolaos K. Symeonidis (1984): The excavations in the dwarf elephant cave on the island of Tilos (Dodecanese, Greece) in 1983. - Session reports of the Academy of Sciences, mathematical and natural science class - 193: 321 - 328.
  • J. Bristol Foster: The evolution of mammals on islands. In: Nature . Volume 202, 1964, pp. 234-235.
  • Robert H. MacArthur & Edward O. Wilson : The Theory of Island Biogeography. Princeton University Press, Princeton 1967.
  • Ted J. Case: A general explanation for insular body size trends in terrestrial vertebrates. In: Ecology. 59, 1978, pp. 1-18.
  • Paul AP Durst & V. Louise Roth: Classification tree methods provide a multifactorial approach to predicting insular body size evolution in rodents. In: American Naturalist. Volume 179, No. 4, 2012, pp. 545-553, DOI: 10.1086 / 664611 .
  • MR Palombo: Endemic elephants of the Mediterranean Islands: knowledge, problems and perspectives. In: G. Cavarretta (Ed.): La terra degli elefanti. = The world of elephants. Atti del 1. congresso internazionale, Roma, 16–20 October 2001. Consiglio nazionale delle ricerche, Rome 2001, ISBN 88-8080-025-6 , pp. 486–491, online (PDF; 45 kB) .

Web links

Wiktionary: Island dwarfing  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. Serena Tucci et al .: Evolutionary history and adaptation of a human pygmy population of Flores Island, Indonesia. In: Science . Volume 361, No. 6401, 2018, pp. 511–516, doi: 10.1126 / science.aar8486
    Island living can shrink humans. On: from August 2, 2018
  2. Fr. Bachmayer, N. Symeonidis: The excavations in the dwarf elephant cave on the island of Tilos (Dodecanese, Greece) in 1983 . In: Session reports of the Academy of Sciences, mathematical and scientific class . 193, 1984, pp. 321-328.