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■ David Catchpoole
THERE’S SOMETHING about the way a peacock shakes his fan of spectacularly elaborate tail feathers that at- tracts a peahen’s admiring gaze. It now appears the allure is indeed in the motion, not (as had once been thought)
the size of the male’s feathery train, or the number of its colourful
eyespots. Researchers using high-speed video found that the tail
vibrates at an average frequency of around 26 beats per second.
The peacock sustains this for more than 25 minutes at a time.
When the peacock vibrates his tail, it seems those ‘eyes’ can
hypnotize the one he is trying to woo.1 When the train is rattled,
the vibration of the tail feathers creates a “dynamic iridescent
background” around each eyespot. 2 The behaviour of the eyespots
during tail-shaking is remarkable—not their movement as such,
but their apparent non-movement. While feather barbs in the background, even near the eyespots, moved laterally by up to 9. 6 mm,
the eyespots themselves had a maximum side-to-side movement
of just 1.7 mm.
From the peahen’s perspective (typically 1 metre directly in
front), the researchers say “the eyespots would appear to be almost
stationary” relative to the stunning dynamic iridescence shimmering from the rest of the tail. 2 No wonder she’s mesmerized.
But how can the eyespots stay relatively still when the whole
tail is shaken vigorously? Scanning electron microscopy revealed
that the eyespot feather structure is different. Eyespots are heavier,
Avoiding the logical conclusion of intelligent design, today’s
evolutionary storytellers might seek to use this discovery to revive
Charles Darwin’s theory of sexual selection for the peacock—that
its tail evolved to attract a mate (periodically hotly disputed by
evolutionists themselves4). But sexual selection arguments still
fall under the fallacy of using biological advantage of a current
system as ‘proof’ of a neo-Darwinian origin of that system. The
basic problem remains unresolved; such an unwieldy tail would be
a huge handicap for the peacock’s escape from predators.
So wouldn’t it be more sensible to realize that this latest tail-rattling discovery seriously rattles the evolutionary tale, too? (For
those not totally ‘hypnotized’ by it, of course.)
References and notes
1. Secret of how peacocks shake their tail feathers to hypnotise a mate
revealed, abc.net.au, 28 April 2016.
2. Dakin, R., and 4 others, Biomechanics of the peacock’s display: How
feather structure and resonance influence multimodal signaling, PLoS
ONE 11( 4):e0152759, 2016 | doi: 10.1371/journal.pone.0152759.
3. These characteristics are similar to those observed in the primary flight
feathers in other bird species, which show strong evidence of design. See,
e.g., “‘Microstructural architecture’ of feathers makes them tough”, p. 27
4. See creation.com/peacock2 and creation.com/peacock3.
Peacock ‘eyes’ that hypnotize