As the
sun sets on the African Savannah, lionesses can be spotted prowling the open
land, hunting and making kills, often as a group. Males are more often lounging
around during this time, leading some observers to the assumption that they’re
lazy, poor hunters, and take advantage of the females’ kills as their food
source, says Scott Loarie, of the Carnegie Institution for Science. However,
when Loarie heard repeated anecdotes of naturalists coming upon males
successfully making kills in more hidden areas, he began to suspect that
they’re not such bad hunters after all, but might have a different strategy
than females.
To probe
how, where, and when male and female lions hunt, Loarie and his collaborators
combined two technologies. They first fastened GPS collars onto lions at South
Africa’s Kruger National Park, allowing them to track where each lion wandered
throughout the day and where and when it hunted. Then, they flew an airplane
over the park and used Light Detection and Ranging (LiDAR), a form of radar, to
get high-resolution imagery of all of the vegetation patterns in the area. With
LiDAR, the scientists could not only see the upper level of the forest’s
canopy, like previous satellite images had provided, but each plant layer
beneath. It offered the most detailed images yet of the structure of the Park’s
flora.
By
combining the two data sets for the first time, Loarie’s team could draw
conclusions about how male and female lions use different types of landscapes
for hunts.
“Females
are hunting and lounging in the same areas,” Loarie explains. “The females team
up to hunt in groups in these open areas,” he says. “While the males lounge in
more open areas and then go to denser parts of the landscape to hunt.”
This
research not only begins to explain how male and female lions’ hunting
strategies differ but also provides information on how changes to vegetation
could impact the predator–prey balance in Africa.
“We’ve
just done the very first step of saying there’s this causal relationship
between lion hunting behavior and vegetation,” Loarie says. “But what does that
tell us ultimately about ways we can manage these parks to ensure that this
menagerie of biodiversity can continue to exist?” he says.
Loarie
plans to apply the combined LiDAR–GPS tag technique to other animals to further
explore the relationship between animal predator–prey behavior and vegetation.
His team is currently analyzing data on the sable antelope.
“Once
ecologists become more comfortable with these technologies, we can apply them
more and more to fields like animal behavior which have mostly been done in the
past with naturalists in the field with a pad of paper and a pen,” says Loarie