Usage & abusage - In brief

Though less perfect than the leaf insect (p. 21), this leaf-mimicking katydid from Brazil also uses camouflage to enable it to blend with the foliage. © Patrick Ageneau/Musée des Confluences, Lyon (FR)
Though less perfect than the leaf insect (p. 21), this leaf-mimicking katydid from Brazil also uses camouflage to enable it to blend with the foliage. © Patrick Ageneau/Musée des Confluences, Lyon (FR)
Female rhesus monkey showing an interest in wheeled objects. © Yerkes National Primate Research Center
Female rhesus monkey showing an interest in wheeled objects. © Yerkes National Primate Research Center

Crafty bird

The striking and flamboyant killdeer (a species of plover) is a North American shorebird with a few tricks up its sleeve. Should a predator come too close to its nest or young, it will either attack directly or use the ‘broken-wing ploy' to distract the predator. This involves the killdeer hobbling away from its nesting area holding its wing as though it were broken, then flapping around on the ground and emitting a distress call. This tricks the predator into following what it sees as easy prey. After continuing to hobble for a while, the killdeer suddenly flies off. Meanwhile, its fledglings have remained safe and sound, either by keeping quiet and staying put or by scattering in all directions.


Boy toys, girl toys...

Researchers at the Yerkes National Primate Research Center at Emory University in Atlanta (USA) were interested in testing differences in behaviour between male and female monkeys. They set out to test their taste in toys, which in humans tends to be rather gender-specific, e.g. cars, drums or guns for boys, and dolls, cooking utensils and other ‘feminine' articles such as stuffed animals for girls. The researchers wanted to find out whether it is society that determines roles and influences choices from early childhood. The team compared the behaviour of 11 male and 23 female rhesus monkeys that had never been subjected to example or exhortation. Like human boys, the male monkeys exhibited a clear preference for wheeled toys. By contrast, the females were much more eclectic and touched all the toys. "As monkeys are not influenced by advertising or criticism regarding toy choice, it suggests that they choose toys on the basis of the activities the toys encourage," explains one of the researchers, Kim Wallen. Sensible monkeys...


Two-voice penguins

Flocks of penguins breed at the same time on the same little patch of land. Before long, the racket is so deafening that even a cat couldn't locate its own kittens, whereas a penguin, be it emperor or king, has no trouble at all. The throng of baby penguins is left to its own devices when the parents go off in search of food - sometimes for weeks at a time.

Even though the fledglings are totally blind and have scarcely any sense of smell, they recognise their parents the moment they return. It's all done by ear. Every penguin has its very own two-voice song. This is because its soundproducing apparatus is a two-part organ (the syrinx) located at the junction of the bronchi. As each branch of the syrinx produces sound independently, it means that a penguin produces two different voices at once. It is the quivering beat generated by the interaction of these two fundamental frequencies that conveys information about individual identity.


Self-medication

Researchers are keenly interested to learn how animals treat their own ills. Michael Huffman (Primate Research Institute, University of Kyoto) is an expert on the subject who has focused his research on the diet of the great apes. It "often consists of a variety of nonnutritional plants, containing secondary metabolites, which suggests that their ingestion has medical benefits." While working in Tanzania, Michael Huffman watched while a female chimpanzee that appeared to be suffering from an intestinal complaint chewed on shoots from the Vernonia amygdalina tree, extracting only the juice. Not surprisingly, the chimpanzee recovered quickly because, as local doctors are well aware, it is an excellent remedy for intestinal parasites. "So we find in the animal kingdom the biological roots of the human use of medicinal plants," he says.


Mimesis and mimicry

Camouflage is a well-known weapon of insects that allows for a range of strategies. Mimesis is common to numerous species and entails melting into the background to escape predators. For instance, some caterpillars, stick insects, butterflies and grasshoppers will imitate leaves. True mimicry is much more subtle. It is a means of openly appearing before predators in the guise of an unpalatable or noxious species. "The most remarkable strategy is when one species passes itself off as another. For this deceit, the vulnerable and palatable mimic species adopts the characteristics of the noxious or vulnerant (and so unpalatable) model species," writes Christian Levêque(1). Some of the most remarkable mimics are species of intertropical butterfly.

  1. Sur les traces du vivant, edited by Christian Levêque, Fage Editions, Musée des Confluences, 2007.

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