Spotted hyenas adjust their foraging behavior in response to climate
change

Date:
April 4, 2022
Source:
Leibniz Institute for Zoo and Wildlife Research (IZW)
Summary:
Spotted hyenas adjust to a decreased presence of migratory
prey in their territories induced by climate change. Researchers
investigated the relationship between rainfall volume and migratory
herbivore presence in hyena clan territories in the Serengeti
National Park, Tanzania, and the responses of lactating hyenas to
recent changes in the climate-prey relationship.



FULL STORY ========================================================================== Spotted hyenas adjust to a decreased presence of migratory prey in
their territories induced by climate change. This is the key result of
a paper recently published in the scientific journal Ecosphere. A team
of researchers from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), Germany, and the Centre for Functional and Evolutionary
Ecology (CEFE), France, investigated the relationship between rainfall
volume and migratory herbivore presence in hyena clan territories in
the Serengeti National Park, Tanzania, and the responses of lactating
hyenas to recent changes in the climate-prey relationship. Using an observation-based dataset spanning three decades, they showed that
the substantial increase in annual rainfall during this time halved the presence of migratory herds inside the hyena clan territories, but did not affect the ability of female hyenas to access their prey and successfully
nurse their young. This suggests a high plasticity of foraging behaviour
of hyenas in response to changing environmental conditions.


==========================================================================
It is crucial to understand the mechanisms and extent to which animals
in diverse ecosystems are resilient to climate change. Changes in the
timing or amount of precipitation can alter vegetation growth and hence
the distribution of migratory herbivores, such as the blue wildebeest (Connochaetes taurinus) and plains zebras (Equus quagga) in the Serengeti ecosystem in Tanzania, East Africa. Climate change may thus ultimately influence the location of profitable feeding areas for predators, such
as spotted hyenas, who feed on these herbivores. A recent paper reveals
that spotted hyenas (Crocuta crocuta)can adjust their foraging behaviour
to shifts in migratory prey presence in their territories that are linked
to recent changes in pattern and amount of rainfall.

Scientists from the Leibniz-IZW and CEFE analysed data from a long-term
project on three clans of spotted hyenas in the centre of the Serengeti National Park.

The three clans have been monitored continuously from 1990 to
2019, on a near- daily basis. Weather data show that total annual
rainfall substantially increased in the Serengeti over these three
decades. Simultaneously, the presence of migratory herds in hyena clan territories essentially halved. "To assess how the hyenas responded
to these changes in rainfall patterns and prey abundance in their
territories, we focused on maternal den attendance -- the presence of
lactating hyenas with entirely milk-dependent offspring at communal dens,"
says Morgane Gicquel, first author of the paper and doctoral student at
the Leibniz-IZW.

The research team found that, over the course of a year, the probability
of migratory herd presence in hyena clan territories increased with
the amount of rainfall two months earlier, and that the probability
of maternal den presence in clan territories also increased with
that of migratory herd presence. As rainfall volume increased over
the years, the presence of migratory herds in hyena clans decreased
because the association between rainfall and herd presence became
weaker. Surprisingly, maternal den attendance did not decrease throughout
the entire study period and still matched periods of high prey abundance.

"The presence of mothers at the communal den is a key behaviour directly related to cub survival. Spotted hyenas in the Serengeti National Park reproduce throughout the year. Their cubs entirely depend on milk for
their first six months of life," explain Dr Marion East and Prof Heribert Hofer, senior scientists at the Leibniz-IZW who investigated the hyenas
in the Serengeti throughout the study period. "When large aggregations of migratory herbivores occur in the clan territory, all lactating mothers
feed inside the territory and nurse their cubs daily. When migratory
herds are absent, there is no other prey around and females fuel milk production by regularly commuting to distant areas to feed on migratory herbivores. After one to several days, they return to the communal dens
to nurse their cubs." It could be expected that a decline in migratory
herd presence within clan territories increases the time mothers spent
away from their cubs searching for prey. So, why did maternal den presence
not decrease in the hyena clans? "Our findings suggest that hyenas may not
so much rely on an expectation of where aggregations of migratory herds
should be on a given month, but rather employ other means of locating
good foraging locations when commuting," says Dr Sarah Benhaiem, senior
author of the paper and senior scientist at the Leibniz-IZW. A hyena
might obtain information on the best direction to set out on a commuting
trip from the direction from which well-fed clan members return to the
den or the scent trail left by these members. Previous research by the Leibniz-IZW team had shown that hyenas use well established commuting
routes which cross many territories. Dr Sarah Benhaiem explains: "The
use of these tracks would allow hyenas to obtain information on foraging success of animals from different clans they encounter on the way. This
could help improve their efficiency in locating distant migratory herds."
"Our results suggest that hyenas appear to be well suited to cope with
changes in the presence of migratory herds in their territories induced by climate change," says Morgane Gicquel. "This indicates a high plasticity
in the response of this keystone predator to environmental variability,"
adds Dr Sarah Cubaynes, a scientist at the CEFE and co-author of the
paper. Although migratory herbivores in the Serengeti National Park are
the main prey of several large carnivore species when they occur in their territories, only hyenas regularly commute long distances outside their
clan territory to feed on migratory herbivores. Even so, the impact of potential changes in migratory herbivore movements might also affect
other carnivores in this ecosystem.


========================================================================== Story Source: Materials provided by Leibniz_Institute_for_Zoo_and_Wildlife_Research_(IZW).

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Morgane Gicquel, Marion L. East, Heribert Hofer, Sarah Cubaynes,
Sarah
Benhaiem. Climate change does not decouple interactions between a
central‐place‐foraging predator and its migratory prey.

Ecosphere, 2022; 13 (4) DOI: 10.1002/ecs2.4012 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220404105732.htm

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