Kurz vor der Eiablage fressen Pinguinweibchen Muschelschalen, um sich eine Extraportion Kalzium zu holen. Nur so können sie genügend Kalk für die extradicken Eierschalen produzieren, die ihre Eier vor dem Zerbrechen auf dem harten Untergrund schützen. Das haben amerikanische Biologen entdeckt, als sie mehr als 10.000 Eierschalen und die Ernährungsgewohnheiten argentinischer Magellanpinguine untersuchten. Über die Ergebnisse von Dee Boersma und ihren Kollegen berichtet die Universität von Washington. www.wissenschaft.de
Calcium makes up slightly more than one-third of the average penguin eggshell. Where does the calcium come from? According to a study published in the January issue of The Auk, a quarterly journal of the American Ornithologists' Union, family-minded penguins may ingest and retain in their stomach the tough shells of mollusks as a supplemental calcium source. … This habit of ingesting calcium-rich items, such as shells, grit, ash or bones, is considered to be rare among seabirds since their regular diets are high in calcium from fish and shellfish. But the supplement gives Magellanic penguins one of the thickest seabird eggshells around - an important insurance policy for eggs laid on the hard Patagonian ground. … Boersma, her colleagues and a large number of students and volunteers from the United States and Argentina examined 10,023 eggs between 1984 and 2001. After ruling out those broken by predators (birds, skunks, foxes and the occasional armadillo), they tallied only 257 eggs that broke before hatching - 2.6 percent of the total yield. americanscientist.org/issues/pub/south-beach-diet
The whole study / The whole story:
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