1. A Pilot Study Quantifying Xenopus laevis Swimming Behavior
Through Infrared Technology
David Chu1, Nay Lui Saw3, Sherril Green1, Mehrdad Shamloo1,2, 3
Comparative Medicine1, Neurosurgery2, Behavioral & Functional Neuroscience Lab3
Intro & Abstract Materials and Methods
Results
Discussion
Xenopus laevis has emerged as a
preeminent amphibian animal model in
fields of vertebrate cell and
developmental biology and more recently
oncology as well as drug discoveries.
Although we have a good understanding
of their laboratory husbandry and care
conditions, we still need to better
elucidate Xenopus behavior in captivity if
we wish to use their behavior as a
research paradigm. We tracked a mature
female’s swimming distance and water
column preference from 16:00 to
10:00 the following morning within a 10
gallon aquarium. Results showed that the
female swam 259 horizontal meters in 18
hours; 16.4 meters per hour during the 12
hour dark phase and 10.3 meters per hour
during the 6 hour light phase with 93%
and 7% of time on water column bottom
and top, respectively. We expanded this
investigation by tracking mature females’
swimming distance over 200
hours within converted standard
polycarbonate rat cages. We provided
husbandry (feeding and physically
moving frogs to cage with clean water) at
hour 135. For the first 135 hours, frogs
again demonstrated higher nocturnal
activity with an average of 86.8 meters
per hour during dark phase and 36.8
meters per hour during room’s light
phase. Interestingly, dark and light phase
swimming distance plummeted
dramatically to 23.1 meters per hour and
12.1 meters per hour, respectively, for the
final 83 hours after physical manipulation
(husbandry service). Results clearly
demonstrate this specie’s nocturnal
nature in the laboratory and its propensity
to “lay low” after physical handling.
Although we’ve gained additional
insights into Xenopus frog’s swimming
behavior, one should exercise caution
when using this paradigm if the study
involves frog handling.
 Chum H. et al. Biology, behavior, and
environmental enrichment for the
captive African clawed frog (Xenopus
spp). Appl Anim Behav Sci 143:150-
156.
 Erichsen J. and Woodhouse J. 2012.
Human and Animal Vision. In:
Batchelor B. (editor). Machine Vision
Handbook. London: Springer-Verlag
p 89 – 115.
 Green S. 2010. The Laboratrory
Xenopus sp. Boca Raton: CRC Press.
 Tomhave B. [Internet]. Xenopus
tropicalis behavior: Is activity level
based on presence or duration of
light? [cited August 28, 2015]. At
https://prezi.com/mkyaag1hdhwk/xen
opus-tropicalis-behavior-is-activity-
level-based-on-presence-or-duration-
of-light/
 Witkovsky P. et al. A micro-
spectrophotometric study of normal
and artificial visual pigments in the
photoreceptors of Xenopus laevis.
Vision Res 21(6):867-73
References
Work was approved by the IACUC (#22935). Water (pH: 7.5-8.5, conductivity 500-
3000 μS, total dissolved gas < 102%) was tapped from Aquatic Habitat modules.
Session 1: We tracked a mature female’s swimming distance and water column
preference using Ethovision XT automated tracking system (Noldus Information
Technology, Wageningen, the Netherlands) equipped with infrared cameras from
16:00 until 10:00 the following morning within a standard 10 gallon glass aquarium
(figure 1). Camera was placed on a tripod and data was recorded and analyzed.
Session 2: We tracked two mature females’ horizontal swimming distance over 200
hours within converted standard polycarbonate rat cages. Outer surfaces of rat cages
were sprayed with non-toxic black paint and tops were covered with clear Plexiglass.
Infrared cameras were mounted above cages. At hour 135 we paused recording and
provided husbandry (fed 10 Xenopus Brittle pellets per frog and manually moved
frogs to cages with clean water 3 hours post feeding). Water was allowed to
equilibrate to room temperature prior to frog transfer. We continued recording at
hour 144 to hour 210.
Session 1: Frog demonstrates
higher activity level when lights
are off from 19:00 to 07:00.
These four panels depict
activity pattern and level within
60 minute increments. Frog
swam 259 horizontal meters in
18 hours; 16.4 meters per hour
Figure 1. The arena was divided into four zones
top left (TL), top right (TR), bottom left (BL),
bottom right (BR) for the first recording session.
http://sbfnl.stanford.edu/
time on water column bottom (BL+BR) and top
(TL+TR), respectively.
Session 2 (left charts): For the first 135 hours,
the two frogs demonstrated higher nocturnal
activity with an average of 86.8 meters per hour
during dark phase (gray bars) and 36.8 meters
per hour during light phase (white bars).
Swimming distance plummeted dramatically to
23.1 meters per hour and 12.1 meters per hour,
respectively, for the final 83 hours post
husbandry service.
during the
12 hour
dark phase
and 10.3
meters per
hour during
the 6 hour
light phase
with 93%
and 7% of
 This pilot series demonstrates the
utility of continuous infrared light
recording of an aquatic lab animal
species over several days.
 IR is 0.7-1000 mm and Xenopus
retinal cones are reported to have
absorption spectrum of about 0.6 mm
so IR during dark cycle should be
“invisible” to African clawed frogs.
 This methodology potentially may be
adapted to gain further insights on
aquatic animal behaviors and
preferences.