18 | New Scientist | 13 February 2021WHAT’S in a somersault, a flap
of the lip or a spit of water in the
face? More than meets the eye,
it seems. They may all be new
ways of communicating that
orangutans have come up with
in captivity. This suggests that
such gestural creativity may
be ancestral in the great ape
line, adding a new piece to the
puzzle of language evolution.
Using new expressions to
convey things, known as
productivity in the field of
linguistics, is one of the
fundamental building blocks
of complex language, and
it is rarely reported in the
animal kingdom.
Instead, most animals
have a fixed set of messages,
the meanings of which are
determined by the context,
such as the arrival of a predator.
These signals seem to be innate
rather than being learned.
Humans clearly show
productivity, but whether
other apes do is debated.
To explore, Marlen Fröhlichat the University of Zurich in
Switzerland and her colleagues
examined whether orangutans
held in captivity in zoos
have developed new ways
to communicate that aren’t
seen in their wild peers.
Zoos offer orangutans a
stable yet different ecological
niche. Getting food is less of an
issue, as is avoiding predators.
In the wild, orangutans tend
to live rather solitary lives.
In zoos, they live in larger
groups in close proximity to
one another, with more social
interaction. They spend moretime on the ground, away from
foliage that can disrupt their
view of other orangutans.
All of these factors may help
establish an environment in
which productivity can flourish.
Fröhlich’s team suggests that
zoo living really has made a
difference. The group looked
at information on more than
8000 examples of non-vocal
orangutan communications
by 30 individuals in five zoos,
and 41 in wild populations
in two forests.
After identifying and
categorising the full range of
signals, the team focused on
those seen exclusively either in
wild or in captive populations.
Seven signals were used
only in zoos, whereas only
one was exclusive to the wild.
The zoo-only signals include
a head-stand and a repeated
spit of water in the face.
The results suggest an
increase of around 20 per
cent in the gestures and facial
signals of captive orangutans
compared with those in the
wild. Most of the zoo signals
were used to invite play, or toget food (bioRxiv, doi.org/ftj2).
Fröhlich and her colleagues
declined to discuss the
work before it has been
fully peer reviewed.
“The study provides
convincing evidence for
innovation with regard to
communicative signals in
orangutans,” says Christine
Sievers at York University in
Toronto, Canada. She notes,
however, that there may have
been observational difficulties
in the wild habitats, which could
have influenced how much
innovation was spotted there.
Simon Townsend at the
University of Warwick, UK, says
the study “adds to the growing
body of data that indicates
signalling in great apes may
be more plastic than previously
thought, with obvious
implications for the evolution
of human language, arguably
the most productive and
flexible communication system
in the animal kingdom”. ❚THE decline of butterfly collecting
as a hobby is making conservation
and ecology research more difficult
for entomologists, according to an
analysis of 1.4 million specimens
held in US museum collections
dating from the 1800s.
Although butterfly collecting
is often seen as a Victorian-era
pastime, Erica Fischer at King’s
College London and their colleagues
actually found that the largest
growth in US specimen numbers
occurred between 1945 and 1960,
showing an 82 per cent increase.
This may have been driven by
college-educated veterans who
received free tuition after the
second world war, the researchers
say. The number of specimens
collected in the US then faltered
in the 1960s, and plunged
after 1990, the team found
(BioScience, doi.org/ftt9).
Fischer says that instead of
collecting physical specimens,
amateurs these days are more
likely to gather observational data,
particularly photos posted to online
databases. While useful, photos
don’t let researchers analyse
DNA, chemical ratios, internal
organs or the pollen found clinging
to specimens, says Fischer.
For example, in a 2018 study,
Heidi MacLean at Aarhus University
in Denmark and her colleagues
examined specimens of the Mead’s
sulphur butterfly (Colias meadii)
collected over the course of
60 years at Loveland Pass, Colorado,
to see how they adapted to climate
change by changing colour. “We
couldn’t have done it without the
actual specimens,” says MacLean.
Fischer is now studying
collections of butterflies and
moths in UK museums to see
if the same collecting decline
holds true and to assess the cultural
forces behind the change. “Is it
that science has moved away
from collections?” says Fischer. ❚Orangutans use gestures
as well as calls to get
their message acrossLanguage BiologyRichard Kemeny Madeline BodinRMASIA/
AL
AMYNews
“Seven gestures and
facial signals were
used only by orangutans
living in zoos”
Orangutans in zoos create
new communication signals
Ecological research
harder due to lack of
butterfly collectors