Female bushbabies more stressed, may be more vulnerable to changing environment

Date:
November 10, 2021
Source:
University of Colorado at Boulder
Summary:
Life isn't always easy for small primates in the Soutpansberg
Mountains of South Africa -- foraging for food, contending with
cold temperatures and fighting off rivals. A new study explores
how they may weather the environmental changes ahead.



FULL STORY ==========================================================================
A new study has explored the yearly routine of a small primate called
the thick-tailed greater galago (Otolemur crassicaudatus), discovering
that females may be under a lot more stress than males.


==========================================================================
The findings raise possible alarm bells for the conservation of greater galagos, sometimes called bushbabies, which are native to sub-Saharan
Africa, and other primate populations across the globe -- especially
ones in which females carry the sole burden of raising offspring. The researchers, including anthropologist Michelle Sauther of CU Boulder,
published their results Oct. 25 in the journal Conservation Physiology.

"There's been a trend of decreasing primate populations around the
world over the last few years," said Channen Long, lead author of the
new study and a doctoral student at the University of Pretoria in South
Africa. "We're trying to see if there are any driving forces that could
be affecting these galagos now or might affect them in the future."
The team's new study takes a journey to the Lajuma Research Centre,
sitting at an altitude of 1,200 meters (4,000 feet) and higher, in the Soutpansberg mountains of northern South Africa. Here, you'll find five
primate species, including greater galagos. They grow to about the size
of a small housecat and have bushy tails.

The International Union for Conservation of Nature (IUCN) currently
lists the cute primate's status as "least concern." But bushbabies
face a number of threats from humans, and have been killed by cars,
power lines and dogs. In recent years, temperatures in the mountain
range have also soared, while humans have leveled forests to make room
for macadamia farms and other agriculture, Long said.

To get a better idea of what may lie in store for the bushbabies,
the researchers collected 186 fecal samples from wild bushbabies
at Lajuma. They then tested those samples for the byproducts of glucocorticoids, a class of hormones that mammals produce when they're
coping with stressful conditions.

The team discovered that female bushbabies seem to experience sharper
increases in the hormones than males. That usually happens in the Southern Hemisphere springtime, or around October and November, when females give
birth and nurse their young.



========================================================================== Those patterns, Sauther said, could hint that female bushbabies will
have less wiggle room to work with as they try to survive in a changing environment.

"One thing that always surprises me is how resilient wild animals can
be," said Sauther, professor in the Department of Anthropology at CU
Boulder. "They have a lot thrown at them in their environments, and they
deal with it quite well.

But everybody reaches their limit." A bruising life Sauther has spent
years traveling to Lajuma to study the primates there.

Winters can get chilly in the Soutpansberg mountains, she said, dipping
down to lows of about 0 degrees Celsius (32 degrees Fahrenheit).

During her time in those forests, one particular bushbaby stood out
for the anthropologist. He was a male who was missing an eye and always
seemed to be getting in fights with other males over females. Sauther
and study coauthor Frank Cuozzo, a CU Boulder alumnus, nicknamed the
primate Bruiser.



========================================================================== "These galagos are quirky," Sauther said. "They have a lot of interesting personalities." Such a hard-knock life, however, can take a toll on an animal's body. Study coauthor Juan Scheun explained that when mammals experience stress -- they get beat up, say, or can't find enough food --
their bodies will produce a pulse of glucocorticoids.

"It helps animals to get more energy," said Scheun, a postdoctoral fellow
at the University of South Africa. "It gives you that extra oomph you
need to survive." Too much of that oomph, however, can backfire. When
animals experience stress for too long, the constant exposure to high
levels of glucocorticoids may weaken their immune systems and even affect
their brain functioning.

In the new study, the researchers set out to discover just how well
Bruiser and his friends and enemies were handling stress in the forests
of Lajuma.

Sex differences The team spent a year hiking through Lajuma, tracking
the animals as they foraged for insects, fruits and tree gum in the
summers and faced leaner times in the winter. They collected monthly
fecal samples from individual bushbaies during that time. Long explained
that poop samples contain a record of the byproducts, or metabolites,
of glucocorticoid hormones.

She added that the team assumed that those hormone levels would jump up
in males during the mating season from June to August when they tussled
over females.

"I was expecting to see some sort of elevation within that winter period
during the mating season, but we didn't see anything," Long said.

Scheun noted that the team's findings may indicate that female and male bushbabies face different pressures in their environments -- a finding
that he thinks could prove true in some other primate species. When it
comes to protecting at-risk species, in other words, the sexes may not
always be equal.

"In most mammals, females carry the brunt of the work, especially
around raising young," Scheun said. "For a lot of primate species,
I think you're going to need to look at sex differences when making conservation decisions." Other coauthors of the new study include CU
Boulder alumnus James Millette and Adrian Tordiffe and Andre Ganswindt
of the University of Pretoria.

========================================================================== Story Source: Materials provided by
University_of_Colorado_at_Boulder. Original written by Daniel
Strain. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Channen Long, Adrian Tordiffe, Michelle Sauther, Frank Cuozzo, James
Millette, Andre Ganswindt, Juan Scheun. Seasonal drivers of faecal
glucocorticoid metabolite concentrations in an African strepsirrhine
primate, the thick-tailed greater galago (Otolemur crassicaudatus).

Conservation Physiology, 2021; 9 (1) DOI: 10.1093/conphys/coab081 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211110131639.htm

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