68 Science & technology The Economist January 29th 2022
In a second trial using the same data
sets, the pets Lab arranged for Oblivious
Software, a company in Dublin, to test
“trusted execution environments”, also
called “enclaves”, as a form of input priva
cy. To set these up data are first encrypted
by their keeper and then sent to a special,
highly secure server that has been built in a
trustworthy way, so that every operation
can be tracked and its memory fully
cleared after the job is done.
Once safely stored in this server’s hard
ware, the data are decrypted and the de
sired analysis performed. For extra securi
ty, cryptographic hashes and digital signa
tures are applied, to prove that only autho
rised operations have taken place. The
output is likewise statistically blurred, us
ing differential privacy, before being sent
back to the original inquirer.
In the tests, both approaches did indeed
spot anomalies. For example, although
American and Canadian records of the val
ue of wood pulp traded between the two
countries were basically the same, their
data on the value of the clock trade differed
by 80%. “Techwise, it worked,” gushed
Ronald Jansen of the unstatistics division,
who administers the new lab.
Whether it works bureaucratically re
mains to be seen. But the putative benefits
would be great. The use of pets offers not
only a means of bringing together data sets
that cannot currently interact because of
worries about privacy, but also a way for all
sorts of organisations to collaborate se
curely across borders.
The pets Lab’s next goals are to dive
more deeply into trade data and to add
more agencies to the roster. This all comes
as many governments take a bigger inter
est in pets. In December America and Brit
ain announced they plan, this spring, to
launch a “grand challenge” prizearound
pet systems. The sharing of data—and
their use—may now be getting easier.nIt’s in here somewhere!ConservationSave the rhino,
save the plant
A
llspeciesofrhinocerosareintrouble,
as poachers kill them to take their
horns. But Sumatran rhinos are in extremis.
Fewer than 80 remain alive, and that hand
ful is scattered between three groups in Su
matra and one in Borneo. This is terrible
news for the species itself. But Kim McCon
key and Ahimsa CamposArceiz at the Uni
versity of Nottingham, in Britain, think it
has wider ramifications—for, as they ex
plain in a paper in Biotropica, several plant
species also depend on Sumatran rhinos
for their survival.
A large proportion of a Sumatran rhi
no’s diet is fruit. The evolutionary bargain
between frugivores and plants is that the
plants coat indigestible seeds with tasty
and nutritious pulp as payment for the fru
givores’ dispersal of those seeds by defeca
tion far from the plant that produced them.
Some plants, indeed, go further. Their
seeds will not germinate unless they have
passed through an animal’s digestive sys
tem. This arrangement works well as long
as suitable frugivores are available. But for
plants with large seeds, these need to be
big animals. And of those, there may be a
restricted supply.
Dr McConkey and Dr CamposArceiz
suspected that this might be a problem for
a number of SouthEast Asian plants which
live in the range once occupied by Suma
tran rhinos. Nor is this a theoretical threat.
Madagascar hosts many endangered
plants, including baobabs, palms and
members of the Proteaceae (a group repre
sented elsewhere by the macadamia nuttree) known by botanists as orphans of ex
tinction. The reason for this moniker is
that the large frugivores, such as giant le
murs, which used to disperse their seeds
were exterminated when people arrived on
the island in the first millennium ad.
In the case of Sumatran rhinos, an alter
native means of seed dispersal may be
available. The local elephants are certainly
large enough to eat the seeds in question. If
they actually do so, then the problem is di
minished. But, when Dr McConkey and Dr
CamposArceiz began their study, the ex
tent to which elephants’ and rhinos’ diets
overlapped was unknown.
To investigate, they and their col
leagues scoured 18.5km of forest trails in
Way Kambas National Park, in Sumatra, for
rhino faeces. Over the course of two and a
half months they discovered 48 piles of the
stuff (29kg in total), and sifted through
these for seeds, which they brought back to
their laboratory for identification.
They also delved into history. First, they
interviewed members of the Orang Asli, a
group of people indigenous to Peninsular
Malaysia, across the Malacca Straits from
Sumatra—and to its forests, in particular—
to obtain their recollections. Sumatran rhi
nos still existed in the Malay Peninsula less
than 20 years ago, and though they are now
gone, memories of the animals, including
what they ate, remain.
To cap things off, the researchers then
ran a literature search in which they exam
ined the accounts of explorers, hunters
and scientists who had come across Suma
tran rhinos in other parts of SouthEast
Asia during the early 20th century, when
they ranged more widely still. They noted
down every observation concerning the
animals’ diets. Once this was done, they
ran a similar investigation into the diets of
the local elephants, to determine how
much overlap there was.
The result was not good. Elephants turn
out to be picky eaters. Rhinos were the only
recorded dispersers of 35% of the large
fruited species found in the regions where
data were available.
To put it another way, of 79 plants
known to have their seeds dispersed by
rhinos, elephants disperse only 57. Seeds
of the remaining 22 are therefore restrict
ed, if no rhinos are around, to germinating
where they fall. So, if a local population of
one of these plants is destroyed for some
reason, it is unlikely to be replaced. And
there is also a risk of local inbreeding. In
deed, three of the species the researchers
identified are already listed as threatened.
Precisely why elephants do not eat the
fruits of these 22 plants is unknown. But
whatever that reason is, it looks as if al
most two dozen SouthEast Asian plants
should be joining the list of orphansofex
tinction. Short of a deliberate campaignof
planting, their days seem numbered.nIf Sumatran rhinoceroses vanish, other
forest organisms may do so, too