Weekdieren zijn geen watjes: een literatuuronderzoek naar hun harde kant

In a recent article, the second author discussed two moralizing poems by Dutch 17th century writers Cats and Vondel. The poems tell of an oyster who, by tightly closing its valves, was able to k:ill a sea-gull ( or a rat in the case of the Vondel poem). Schipper's article was the start of a discussion between the two authors. Were these poems based on older written sources, or on actual observation? A search of the literature resulted in many anecdotal reports, and a few scientific studies, of bivalve aggression. In these reports, both marine and freshwater bivalves were found to be responsible for the mutilation (of mandibles, legs and toes) or even death of different species of birds and mammals. Victims included: oystercatcher, dunlin, knot, redshank, heron, gull, tem, plover, eider duck, cormorant, mouse, rat, fox, hare. The larger mammals were apparently taken by clasping their head or their tongue between the two valves (or a limpet in the case of the hare). Besides birds and mammals, many other types of animals have been reported with attached mollusks. Even a fata! accident, caused by a large abalone, with a human has been reported.