Vol. 39 No. 2, 2000
No Divergence of Habitat Selection between Male and Female
Arboreal Snakes, Trimeresurus s.
Tu*, Shiuang Wang and Yu-Chun Lin
of Biology, National Taiwan Normal University, Taipei, Taiwan 116
Tu, Shiuang Wang and Yu-Chun Lin (2000) Sexual dimorphism in
body size is a common phenomenon among animals, and possibly allows the
sexes to exploit different habitats. In snakes, low body mass is
valuable for arboreal life because it enables the exploitation of a
wider range of habitats. Therefore, we would predict that larger and
heavier female arboreal snakes, Trimeresurus
s. stejnegeri, may use
thicker or lower branches than males. We visited 2 field-sampling sites
and 1 outdoor enclosure regularly to check the micro-habitats that were
used by adult T. s. stejnegeri.
Totally 872 observations of 202 mature snakes were recorded from August
1996 to October 1997. The results contradicted our expectation. No
difference in habitat selection between females and males was found in
the measured parameters. Limited differences in size between the sexes
and the physical structure of plants may account for this negative
result. All snakes perched on thinner twigs more frequently than
thicker branches. Twigs of diameter larger than 2 cm were rarely used
by snakes. We found a significant vertical movement between day and
night by the individuals in all 3 locations. Snakes in the outdoor
enclosure showed a greater tendency to perch on higher branches than
did those in the field. In the field, more than 93% of snakes were
found at a height of less than 4 m. However, less than 64% of snakes
were found within 4 m of the ground in the outdoor enclosure.
Key words: Habitat,
Sex, Arboreal, Snake, Pitviper.
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