26 October 2019 | New Scientist | 19EcologyChildhood NeuroscienceDesert ants are
world’s fastestSaharan silver ants can
run at almost a metre
per second, covering
100 times their own
body length in that time.
Researchers used a
high-speed camera to
see that the ants take
over 40 steps per second
to reach such speeds
(Journal of Experimental
Biology, doi.org/dcvp).Whales trap prey
with their flippersHumpback whales use their
flippers to swat salmon
into their mouths. A team
found that the whales first
generate a net of bubbles
to confine prey near the
water’s surface. They then
guide the prey towards
them with their flippers
while lunging with an open
mouth (Royal Society Open
Science, doi.org/dcvn).More Neanderthal
DNA found in peopleWe know that many people
have tiny bits of DNA that
come from extinct species
of human. One of the first
studies to look for longer
sequences has analysed
genomes of people from
Melanesia in the Pacific.
It found one sequence that
came from Neanderthals
and one from Denisovans
(Science, doi.org/dcvq).Too much snow may
doom Arctic speciesMORE extreme Arctic weather
may threaten the survival of
wildlife there. In 2018, it snowed
so heavily that some areas
remained covered in snow well
into summer, stopping many
plants and animals breeding.
“If this is a one-time event, it’s
not an issue,” says Niels Martin
Schmidt at Aarhus University in
Denmark. Arctic wildlife can cope
with occasional bad years, he says.
But he fears it could become muchPLAYING with a baby may help
shape their hormone system for
social interaction, possibly creating
more receptors for oxytocin, also
known as the “cuddle chemical”.
Kathleen Krol at the University
of Virginia and her team recruited
101 mothers and their babies for
two play sessions – at 5 months and
18 months of age. Interaction, such
as how close mother and baby were
and eye contact, was observed.
Each time, DNA was taken from
mother and baby, so the team could
look at epigenetic modifications to a
gene that codes for the receptor for
oxytocin. These modifications don’t
alter DNA but can control geneactivity. One, known as methylation,
suggests the gene is “switched off”.
Between the two play sessions,
the mothers’ levels of methylation
at the oxytocin receptor gene stayed
constant. But the levels changed for
babies – those who had experienced
more involved play had a fall in
methylation, while those who
received less attention had an
increase (Science Advances, doi.org/
dcvv). This suggests that babies
given more involved play have more
oxytocin receptors, says Krol.
It is too soon to draw parenting
advice from this, says Emma
Meaburn at Birkbeck, University
of London. Jessica Hamzeloumore common, possibly leading
to the extinction of some species.
He is part of a team monitoring
ecosystems around Zackenberg
in north-east Greenland. The
growing season there is very short- just July and August – so if the
ground remains covered by snow
too long it has a major impact.
During the past 23 years, on
average only 4 per cent of land has
still been covered by snow by the
third week of July – the height of
summer. In 2018, it was 45 per
cent. For the first time since
monitoring began, almost all
plants and animals failed to breed.
Closing in on secrets
of our mental powerHOW did humans get to be so
much cleverer than other apes,
given the lack of major structural
differences in our brains
compared with theirs? One
counter-intuitive idea is that it was
to do with a slowdown of our brain
growth during fetal development.
The suggestion comes from a
study that used the relatively new
approach of growing embryonic-
like stem cells in a dish and
coaxing them to turn into nervous
system cells until they form pea-
sized three-dimensional clumps
known as organoids. These are
also called “mini brains”.
Gray Camp at the Max Planck
Institute for Evolutionary
Anthropology in Leipzig,
Germany, and his colleagues
used stem cells from humans,
chimpanzees and macaque
monkeys to grow mini brains for
each species. After four months, a
key difference was that the nerve
cells in the chimp and monkey
organoids were more mature.
Identifying such differences
may be a step towards explaining
why humans are more intelligent,
although the team doesn’t
speculate on exactly how its
findings might relate to this
puzzle (Nature, doi.org/dcws).
Clare WilsonSome migratory birds starved as
they waited for the snow to melt
(PLoS Biology, doi.org/dcwq).
There was heavy snow across
much of the Arctic in 2018, not
just north-east Greenland, says
team member Tomas Roslin
at the Swedish University of
Agricultural Sciences in Uppsala.
While many people assume a
warming world means less snow,
this isn’t the case in colder regions
where the air is usually relatively
dry. As the Arctic warms and sea
ice shrinks, the air gets moister,
meaning more snow can fall
when conditions are right. MLPCloser play with a baby could
pave way to a cuddlier future
VERENA WAHL
BETSIE VAN DER MEER/GETTY IMAGESReally brief
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