Abstract

1
The Comparison of Behavioral Convergences among
the Mammalian Orders Carnivora and
Rodentia.Bethany WestrickBiology
DepartmentBellarmine University
Abstract The purpose of this research is to
observe and analyze the behaviors of three
different mammalian species from the orders
Carnivora and Rodentia to determine behavioral
convergences and the link to evolutionary
convergences. The research conducted for this
project studied the behaviors of species
representing different mammalian orders
Carnivora and Rodentia. From the Carnivora order,
meerkats (Suricata suricata) were observed, and
from the Rodentia order, degus (Octodon Degus)
and gerbils (Meriones unguiculatus) were
observed. The degus and gerbils can be further
categorized into suborders. The degus belong to
suborder, Hystricognathi, and the gerbils belong
to suborder Sciurognathi. Although the different
species belong to different orders, other
similarities, including behaviors exhibited by
the animals can be seen. All three of the species
are primarily native to desert-like habitats,
live in social settings, and are burrowing
mammals. By observing behavioral convergences of
the different species belonging to different
orders, it may be possible to like this to an
evolutionary convergence as well.
Materials and Methods Video analysis was used to
record the behaviors of the meerkats, degus, and
gerbils. Due to the nature of this research being
an observational study of naturally occurring
behaviors, it was important for the recording to
have as small an impact as possible on the
animal. To achieve this, the video camera was set
up to record while the observer vacated the area
under surveillance. This provided an opportunity
for the animals to act more naturally as if no
one was watching them. Once video data collection
was completed, the tapes were digitized and
downloaded on the computer for analysis. During
this process, the film was watched at least two
times to determine which behaviors were noticed
and chosen for analysis. Significant behaviors
such as stand, sit, and scan are some
examples of noteworthy behaviors. The behaviors
were given one-letter codes to make analysis more
time efficient. When recording the behavior of an
animal it is crucial to notice even the most
subtle behaviors expressed by the animals because
they may prove to be just as important as more
obvious, elaborate behaviors. Once a list of all
behaviors was composed for each species, the data
was analyzed using a program called time-line
analysis. This program compiled the data to
create the frequency of behaviors expressed and
the transitions between the different behaviors.
From the information provided by time-line
analysis, an ethogram was created. (See Figs.
1-A, 2-A, and 3-A). Ethograms are used by
ethologists to study and predict behaviors
exhibited by animals. The ethogram factors in the
frequency of the occurrence of the behavior and
the occurrence among transitions from one
behavior to the next. The size of the square
boxes on the ethogram indicate how frequent a
behavior occurs in relation to the other
behaviors. A larger box indicates the behavior in
the box occurred more frequently than one in a
smaller box. The size of the transition arrows
are also proportional to how frequently the
transition occurs between certain behaviors. A
larger arrow, and the number corresponding with
the arrow describe how frequently the transition
occurred. Ethograms, along with probability, are
useful in predicting behaviors seen in animals.
Graphs of the behavior frequencies using Excel
were also created. All of the data was used to
compare the different animal species for
behavioral and evolutionary convergences. In
addition to this, a chi-square analysis was
completed to examine if a significant difference
existed among the behaviors of the different
species.
Results
Taxonomy
Fig. 1-A Meerkat Ethogram
Fig. 1-B Behaviors Observed in Meerkats
Figure 1
Table 1 Chi-square analysis among the percentage
of behaviors seen in the meerkats, degus, and
gerbils, (MMeerkats, DDegus, and GGerbils).
Frequency
Behavior
Fig. 2-A Degu Ethogram
Fig. 2-B Behaviors Observed in Degus
Meerkats (Suricata suricata)
Discussion As this research shows, behavioral
analysis of an animal can give viable information
about the particular animal. Many evolutionary
convergences can be seen when examining
behaviors. The behaviors observed in the animals
give more insight as to why the animal may have
certain physiological traits. For example
meerkats are found in hot, dry areas where they
may be in the sun many hours each day. As seen in
the Fig 1-A, the meerkat ethogram, the most
frequent behavior exhibited by the animal is the
scan behavior. Most of the animals time is spent
scanning in bright sunlight, and to accommodate,
meerkats have dark fur around the eyes to reflect
the light. In addition to this, meerkats fall
prey to many predators and must scan in an
attempt to avoid predators. The same examples can
be seen in the degus and gerbils. The largest
frequencies exhibited by both species is the sit
and scan behaviors. Again, these animals fall
prey to many predators and must constantly be
aware of potential dangers. All three of the
species examined have long tails which can act to
help balance the animal during long hours of
sitting or standing (behaviors frequently seen in
all three species), making it easier to do for
long periods. From an evolutionary standpoint,
the behaviors aid in survival of the species by
making the individuals more attentive to
predators. The behavioral analysis of the
different mammalian orders, carnivora and
rodentia can be compared to an evolutionary
convergence. Based on biological taxonomy, the
meerkats are members of the order, carnivora
whereas the degus and gerbils both belong to the
order rodentia. The degus and gerbils can also be
divided into further suborders, Hystricognathi
and Sciurognathi, respectively. Based on this, it
can be hypothesized that if behaviors correspond
to evolutionary factors, then the behaviors seen
in the gerbils and degus will be more similar
than those seen in the meerkats, but if there are
still some similarities between all three
species, then this could mean a possible
evolutionary convergence among the mammalian
orders. Chi-squared analysis was used to
determine the significant difference between the
behaviors of the three species. As seen in the
results from the analysis, whenever the degus and
gerbils were compared, there was no significant
difference seen in the frequency of the
behaviors. (See Table 1). This data corresponds
with the fact that these animals are more closely
related on an evolutionary scale since they are
in the same order. However when comparing the
behaviors of the degus, meerkats, and gerbils,
the chi-square analysis shows a significant
difference exists between these behaviors. Any
other significant differences shown by the
analysis occur only when comparing the meerkats
to another species, but there are still some
examples which show no significant difference
between the meerkats and other species. This
entails that even though the meerkats are in a
different order from the degus and gerbils, there
are still behavioral convergences which could
also mean evolutionary convergences. In addition
to this, the chi-squared analysis shows no
significant difference between the degus and
gerbils even though they are in different
suborders. This convergence can also be linked to
an evolutionary convergence. All three
species examined in this research are unique in
the fact that they all are different species in
two different orders. However based on the
similarities seen in the behaviors exhibited by
the animals, they can be more closely linked to
one another suggesting an evolutionary
convergence.
Frequency
Behavior
Photo courtesy of Dr. Bill Tietjen
Fig. 3-A Gerbil Ethogram
Fig. 3-B Behaviors Observed in Gerbils
Degus (Octodon degus)
Frequency
Behavior
Gerbils (Meriones unguiculatus)
Acknowledgements I would like to thank Dr.
William J. Tietjen for all is help and insight
for this research References Cloyd, E. 2003.
"Octodon degus" (On-line), Animal Diversity Web.
Accessed November 21, 2005 at http//animaldiversi
ty.ummz.umich.edu/site/accounts/information/Octodo
n_degus.html Clutton-Brock, T.H., COOPERATION,
CONTROL, AND CONCESSION IN MEERKAT GROUPS, By
Science, 00368075, 01/19/2001, Vol. 291, Issue
5503 Database Academic Search Premier Fitzpatric
k, K. Meerkats (On-line). Accessed November 21,
2005 at http//www.bio.davidson.edu/people/vecase/
Behavior/Spring2004/fitzpatrick/fitzpatrick.htm P
oor, A. 2005. "Gerbillinae" (On-line), Animal
Diversity Web. Accessed November 21, 2005 at
http//animaldiversity.ummz.umich.edu/site/account
s/information/Gerbillinae.html Tietjen, W. J.,
Spider Lab (On-Line). Accessed Novemer 20, 2005
at http//cas.bellarmine.edu/tietjen/