3 0 5 5 1 1 1
2 4 6 2 6 3 0
1 4 0 2 5 4 1
0 4 6 1 0 2
2 3 3 5 0 3 5
0 0 6 2 1 3 5
5 6 1 2 6 6 34 June 2022 | New Scientist | 55Answers
Quick quiz #154
Answers1 Bats
2 1973
3 Yellow fever virus
4 Blood pressure
5 Colorado. The Grand Mesa covers
around 1300 square kilometresCryptic Crossword
#84 AnswersACROSS 6 Bleach, 7 Unrest,
9 Swam, 10 Mediate, 11 Spa day,
13 Gamete, 15 Pom-pom,
17 Gimbal, 18 Obverse, 20 Node,
22 Asking, 23 ScurryDOWN 1 Glow, 2 Dammed up,
3 Whimsy, 4 Sun dog, 5 Area,
8 Spectra, 12 Photons,
14 Momentum, 16 Mirage,
17 Grease, 19 Void, 21 Dark#169 A Domino
Piazza
SolutionA full set of dominoes has eight of
each number. In the piazza, there
are eight 0s and 1s, and seven 2s,
3s, 5s and 6s, so we can be sure
that the 0-0, 1-1, 2-2, 3-3, 5-5
and 6-6 dominoes all appear.6-6 and 0-0 can be identified
immediately, which forces 5-6
(bottom left) and 5-3 (bottom right),
so barriers can now be drawn
between any other 5-3 and 5-6
pairs, and 5-5 must be in the top
row. From this the whole pattern can
be found. The missing dominoes are
4-4, 4-2, 5-4 and 6-3.Tom Gauld
for New Scientist
Wagging question
Why do wagtails wag their tails?
They would be well camouflaged,
if it weren’t for their constantly
moving tails.
Chris Daniel
Glan Conwy, Conwy, UK
On a walk the other day, I spent
several minutes watching a yellow
wagtail darting, its tail bobbing
continuously. I wondered about
the purpose of this behaviour,
then I came home and opened
the edition of New Scientist
with this very question.
Many bird species move their
tails, either bobbing them up and
down like the European wagtails
or waving them from side to side
like the willie wagtail in Australia.
Many other birds also exhibit
tail-flashing or flicking behaviour.
The wagtail’s eponymous
movement is thought to be
an evolutionary adaptation to
enhance feeding by flushing out
hidden insects that it feeds on. A
study has shown that tail-flicking
is a positive predictor of foraging
performance in a juvenile species
of warbler. It may also be used
as a sign of submission to other
birds of the same species and as
a marker of alertness to potential
predators to discourage pursuit,
in a similar way to the tail-flagging
behaviour of deer.
My limited observation of
wagtails is that the rhythmic
movement is almost continuous,
whether or not the bird is feeding,
so more than one of these
explanations for it may be true.
The movement also appears to
be involuntary, superimposed
on other activities such as walking
and preening.Garry Trethewey
Cherryville, South Australia
All animals must negotiate a
lot of conflicting needs. Beingunnoticed is the best way to avoid
being eaten. But to be unnoticed
also entails not venturing out for
food, not seeking or attracting
mates and not proclaiming
ownership of territory.
Many animals are loud,
colourful and display prominently.
The risk is offset by the benefits
this entails, and their ability to
escape danger in other ways.Mike Follows
Sutton Coldfield, West Midlands, UK
The most likely explanation is
that they wag their tails to give
the impression that they are alert,
to encourage predators to look
elsewhere for an easier meal.
It is unlikely that the wagging
is meant to attract a mate, as even
juvenile birds do it, which would
be a waste of energy. Also, the
frequency or amplitude of
wagging doesn’t depend on the
proximity of potential mates.
There is speculation that the
wagging tail flushes out insects,
but this seems unlikely as surely
other species would also have
evolved this trait. ❚“ Being unnoticed is
the best way to avoid
being eaten, but
this also entails not
venturing out for food
or attracting mates”