Unlocking the mysteries of the pecking order
Researchers celebrate 100 years of study in dominance hierarchies

Date:
January 13, 2022
Source:
University of Cincinnati
Summary:
Dominance hierarchies were first described in chickens a century ago
by a Norwegian zoologist who coined the term 'pecking order.' Since
then researchers have examined the intricacies of conflict and
competition in species as diverse as primates, whales, birds
and insects.



FULL STORY ========================================================================== Dominance hierarchies were first described in chickens a century ago by
a Norwegian zoologist who coined the term "pecking order."

========================================================================== Since then researchers such as University of Cincinnati biologist
Elizabeth Hobson have examined the intricacies of conflict and competition
in species as diverse as primates, whales, birds and insects.

Hobson, an assistant professor of biology in UC's College of Arts and
Sciences, has contributed to this discussion in several published studies, particularly in birds such as monk parakeets. This month she co-edited
a special issue of the journal Philosophical Transactions of the Royal
Society B dedicated to a century of research on dominance hierarchies.

Hobson also authored a new study in the journal using data mining
in Google Scholar to examine trends in the field of dominance
hierarchies. She found increasingly more publications on the topic in
each decade, totalling 26,000 published papers in the past 100 years. The growth in published works each decade along with the diverse communities
that are studying the topic suggest dominance hierarchies still captivate researchers for all they teach about animal behavior.

The subject continues to intrigue both the public and researchers because
we as a society are often preoccupied with conflict and competition,
Hobson said.

"Think of the interest we have in sports and competition," Hobson said.

"Figuring out who is the best underlies a lot of what we like to watch." Norway's Thorleif Schjelderup-Ebbe first described dominance hierarchies
in his dissertation in 1921 while studying how domestic chickens both
create pecking orders and understand their place in them. Chickens peck
those with lower status and are in turn pecked by higher-ranking birds.



========================================================================== "He's like the Charles Darwin of dominance hierarchies," Hobson
said. "Many kernels of insight he had 100 years ago hold up today."
It might be easy to see a reflection of our lives in the daily struggle of animals. But Hobson said that would be an oversimplification considering
the vast spectrum of human emotions, our complicated motivations and
our even more complex relationships.

"You want to be careful making one-to-one comparisons," Hobson
said. "It's more of an analogy. What do we see in animals and what
could that potentially tell us about how people interact?" Even so,
people are fascinated by the struggle.

The journal issue was co-edited by Eli Strauss, a postdoctoral researcher
at the Max Planck Institute of Animal Behavior; James Curley, associate professor of psychology at the University of Texas at Austin; and
Daizaburo Shizuka, an associate professor of biology at the University
of Nebraska at Lincoln.



==========================================================================
"Of all the behavioral biology topics, dominance must be one of the
most familiar to nonscientists, probably because power structures are
so intuitively familiar to us," co-editor Strauss said.

But contrary to conventional wisdom, dominance often has more to do
with circumstance and opportunity than good genes or superior size
and condition.

"The idea that the most dominant animals get the most mating opportunities
and resources is not completely wrong, but it's also overly simplistic,"
he said.

Strauss said in some cases, dominant animals face greater risk of
injury from frequent battles defending their position or territory. As a result, some animals don't maintain their status very long. And perhaps surprisingly, over time, many individuals are likely to hold high status
at some point in their lives, he said.

Strauss works in Kenya's Maasai Mara studying spotted hyenas, highly
social carnivores maligned by their unflattering portrayal as villains in
the Disney movie "The Lion King." When it comes to dominance hierarchies,
the movie misses the mark in how it depicts the titular character as
noble and selfless.

"The view that dominant animals act as benevolent leaders of their
groups is wishful thinking that I believe says more about how we view
our societies than it does about the nature of animal social lives,"
Strauss said. "Individuals holding high status use their status to advance their personal interests." In the decades since Schjelderup-Ebbe's first observations, researchers have learned much about dominance hierarchies, including the ways animals signal their superiority to others, the
clever ways they avoid conflict and how factors like group size and
social alliances affect the order.

"Dominance hierarchies in groups are incredibly common. But species
form these systems in ways that might look similar but are managed quite differently," Hobson said.

In some animals, sheer size dictates one's dominance. But more often,
it's not that simple, Hobson said.

Some animals signal their dominance to potential mates, perhaps to preempt conflict with rivals. Hobson said fish like African cichlids adopt vivid
colors when they ascend in rank. Male monkeys called mandrills, too,
have skin colors linked to their hormones.

A key to understanding how these different species manage dominance is comparative analysis. Strauss and his colleagues created a new database
on 135 different species in which dominance data have been published.

"This new package will drastically simplify comparative analyses of
dominance," Hobson said.

Hobson has studied how monk parakeets quarrel with competitors closest
in status to cement their positions rather than wasting effort fighting
the lowest-ranking members of the colony. This strategy may reflect a
high level of cognition.

"In the parakeets I work with, we don't find a strong correlation between
size and dominance. Instead, individuals may need to recognize their
rivals and remember past fights and outcomes to come up with a mental
model of rank," she said. "That's a very different cognitive task than
choosing to fight an opponent simply because it is slightly smaller
than you." Then there is politics. Some animals such as baboons and
hyenas form coalitions to maintain status.

"Coming in and being hyperaggressive can allow you to rise to the top of
the hierarchy. But if your only method of keeping rank is aggression, the moment you let down your guard, someone else can take over," Hobson said.

Hobson said she and her group are excited about pursuing new questions
in the field of dominance hierarchies.

"The more you know, the more you realize all you don't
know," Hobson said. "So will there be fertile ground
for another 100 years of research on the topic? Absolutely." ========================================================================== Story Source: Materials provided by University_of_Cincinnati. Original
written by Michael Miller. Note: Content may be edited for style and
length.


========================================================================== Journal Reference:
1. Elizabeth A. Hobson. Quantifying the dynamics of nearly 100 years of
dominance hierarchy research. Philosophical Transactions of
the Royal Society B: Biological Sciences, 2022; 377 (1845) DOI:
10.1098/ rstb.2020.0433 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220113151428.htm
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