Yahoo – AFP,
Marlowe HOOD, September 13, 2017
Paris (AFP) - Like escaped convicts, elephants in eastern Africa have learned to travel at night and hide during the day to avoid poachers who are hunting tuskers into extinction, researchers reported Wednesday.
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| Normally elephants forage for food and migrate in daylight, while resting under cover of darkness (AFP Photo/TONY KARUMBA) |
Paris (AFP) - Like escaped convicts, elephants in eastern Africa have learned to travel at night and hide during the day to avoid poachers who are hunting tuskers into extinction, researchers reported Wednesday.
Normally
elephants forage for food and migrate in daylight, while resting under cover of
darkness.
But a sharp
increase in illegal hunting driven by the global trade in ivory has forced the
massive land mammals -- against their nature -- to upend their usual habits.
"As
most poaching occurs during the daytime, their transition to nocturnal
behaviour appears to be a direct result of prevailing poaching levels,"
said Festus Ihwagi, a researcher at the University of Twente in The
Netherlands.
In an
upcoming study, Ihwagi details his findings, based on data gathered from 60
elephants in northern Kenya tracked with GPS devices for up to three years
during the period 2002 to 2012.
Working
with the NGO Save the Elephants, which has fitted more than 100 of the animals
with GPS collars, Ihwagi monitored the movements of 28 females and 32 males in
and around the Laikipa-Samburu ecosystem.
Females
live in close-knit families and often have young calves at their side, while
bulls tend to be more solitary.
To
determine how, and to what extent, poaching had changed elephant behaviour, he
compared two sets of data.
The first
measured the distances travelled during the day and at night, and was logged as
a ratio between the two.
The second
-- drawing from the Illegal Killing of Elephant programme database --
identified zones and time periods when poaching was more or less severe.
Slaughtered for ivory
"Simultaneous
elephant tracking and monitoring of causes of death presented a perfect
'natural laboratory'," said Ihwagi.
The
nighttime movements of the elephants increased significantly in sync with
poaching levels, especially for females.
In
high-danger zones, females reduced daytime activity by about 50 percent on
average compared to low-danger zones, Ihwagi told AFP.
Changing
their behaviour in this way may help keep elephants alive in the short run, but
could have long term implications for their survival, he added.
Despite
their intelligence, deeply ingrained foraging strategies and mating patterns
developed on an evolutionary timescale may limit the capacity to adapt.
"For
mothers with very young calves, the risk of predation of the calves by lions or
hyenas would be higher at night," Ihwagi said.
"For
the mature elephants, it implies an alteration of their normal social
life."
The
real-time data from GPS devices could be used as an early warning system to
alert environmentalists and park rangers, the researchers noted.
A sudden
uptick in nocturnal travel, for example, could signal that elephants feel
threatened.
According
to the International Union for Conservation of Nature (IUCN), the number of
African elephants has fallen by around 111,000 to 415,000 over the past decade.
The killing
shows no sign of abating with around 30,000 elephants slaughtered for their
ivory every year, mainly to satisfy demand in the Asian market for products
coveted as a traditional medicine or as status symbols.
"The
escalation of poaching has become the greatest immediate threat to the survival
of elephants," Ihwagi said.
The
findings will appear in the January issue of the Journal of Ecological
Indicators.
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