This chapter is mostly about selection by eyes, but other senses can do the same thing. Fanciers have bred canaries for their songs, as well as for their appearance. The wild canary is a yellowish brown finch, not spectacular to look at. Human selective breeders have taken the palette of colours thrown up by random genetic variation and manufactured a colour distinctive enough to be named after the bird: canary yellow. By the way, the bird itself is named after the islands,* not the other way around as with the Galapagos Islands, whose name comes from a Spanish word for tortoise. But canaries are best known for their song, and this too has been tuned up and enriched by human breeders. Various songsters have been manufactured, including Rollers, which have been bred to sing with the beak closed, Waterslagers, which sound like bubbling water, and Timbrados, which produce metallic, bell-like notes, together with a castanet-like chatter that befits their Spanish origins. Domestically bred songs are longer, louder and more frequent than the wild ancestral type. But all these highly prized songs are made up of elements that occur in wild canaries, just as the habits and tricks of various breeds of dogs come from elements to be found in the behavioural repertoire of wolves. *
Once again, human breeders have only been building on the earlier selective breeding efforts of female birds. Over generations, wild female canaries inadvertently bred males for their singing prowess by choosing to mate with males whose songs were especially appealing. In the particular case of canaries it happens that we know a little more. Canaries (and Barbary doves) have been favourite subjects for research on hormones and reproductive behaviour. It is known that in both species the sound of male vocalization (even from a tape recording) causes the females' ovaries to swell and secrete hormones that bring them into reproductive condition and make them more ready to mate. One could say that male canaries are manipulating females by singing to them. It is almost as though they were giving them hormone injections. One could also say that females are selectively breeding males to become better and better at singing. The two ways of looking at the matter are two sides of the same coin. As with other bird species, by the way, there is a complication: song is not only appealing to females, it is also a deterrent to rival males - but I'll leave that on one side.
Now, to move the argument on, look at the pictures opposite. The first is a woodcut of a Japanese kabuki mask, representing a samurai warrior. The second is a crab of the species Heikea japónica, which is found in Japanese waters. The generic name, Heikea, comes from a Japanese clan called the Heike, who were defeated at sea in the battle of Danno-Ura (1185) by a rival clan called the Genji. Legend tells that the ghosts of drowned Heike warriors now inhabit the bottom of the sea, in the bodies of crabs - Heikea japónica. The myth is encouraged by the pattern on the back of this crab, which resembles the fiercely grimacing face of a samurai warrior. The famous zoologist Sir Julian Huxley was impressed enough by the resemblance to write, 'The resemblance of Dorippe to an angry Japanese warrior is far too specific and far too detailed to be accidental . . . It came about because those crabs with a more perfect resemblance to a warrior's face were less frequently eaten than the others.' (Dorippe was what the crab was called in 1952 when Huxley wrote. It reverted to Heikea in 1990 when somebody rediscovered that it had been so named as early as 1824 - such are the strict priority rules of zoological nomenclature.)
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