Posted by RickFeliz on May 18, 2001 at 11:54:27:
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Birds that mate for life have always been used as an example of successful monogamy and proof that not all males have the roving eye. Recently, I've been reading "Genome" by Matt Ridley and ran across this gem on page 135: "More romantically, the application of genetic fingerprinting to paternity testing has revolutionised our understanding of bird song. Have you ever noticed that thrushes, robins and warblers continue singing long after they have paired up in spring? This flies in the face of the conventional notion that bird song's principal function is the attraction of a mate. Biologists began DNA-testing birds in the late 1980s, trying to determine which male had fathered which chicks in each nest. They discovered, to their surprise, that in the most monogamous of birds, where just one male and one female faithfully help each other to rear the brood, the females mate quite often with neighbouring males other than their ostensible 'spouses'. Cuckoldry and infidelity are much, much commoner than anybody expected (because they are committed in great secrecy). DNA fingerprinting led to an explosion of research into a richly rewarding theory known as sperm competition, which can explain such trivia as the fact the chimpanzee testicles are four times the size of gorilla testicles, even though chimpanzees are one-quarter the size of gorillas. Male gorillas monopolise their mates, so their sperm meets no competitiors; male chimpanzees share their mates, so each needs to produce large quantities of sperm and mate frequently to increase his chances of being the father. It also explanis why male birds sing so hard when already 'married'. They are lookin for 'affairs'". Regards, |
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