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A Comparison Of Adrenal In Toad-Eating And Nontoad-Eating Snakes, Shabnam Mohammadi
A Comparison Of Adrenal In Toad-Eating And Nontoad-Eating Snakes, Shabnam Mohammadi
Biological Sciences Theses & Dissertations
Toads are chemically defended by bufadienolides, a class of cardiotonic steroids lethal to most predators, including many snakes. Bufadienolides bind to Na+K +-ATPase, inhibiting their ability to transport ions. In cardiocytes, this inhibition cause arrhythmia and severely increased contraction strength, which, if prolonged, lead to death. However, several snakes are resistant to bufadienolides and consume toads with no ill effects. Adrenal glands produce hormones that are important for the maintenance of Na+K +ATPase, and may therefore play an important role in countering the negative effects of bufadienolides. Indeed, the toad-eating specialist Heterodon platirhinos has been known to possess enlarged, and …
A Staging Sequence And Analysis Of Growth In Postovipositional Embryos Of Lamprophis Fulignosus, Angela Renee Vogel Rivera
A Staging Sequence And Analysis Of Growth In Postovipositional Embryos Of Lamprophis Fulignosus, Angela Renee Vogel Rivera
Biological Sciences Theses & Dissertations
The brown house snake, Lamprophis fuliginosus, is a small, oviparous snake found throughout much of Africa. This lamprophiine colubrid reproduces rapidly; captive females can lay clutches every three to four months for a sustained period. Thus, L. fuliginosus is an excellent model for developmental studies requiring large numbers of embryos. In addition, the embryos of oviparous species are more suitable for some procedures than are those of viviparous forms. The most widely used system for staging embryonic snakes was developed for the common gartersnake, Thamnophis sirtalis, a viviparous natricine colubrid (Zehr, 1962). Based on the examination of 135 …
Movement Patterns And Habitat Use Of The Copperhead Snake (Agkistrodon Contortrix) In Southeastern Virginia, Christopher Edwin Petersen
Movement Patterns And Habitat Use Of The Copperhead Snake (Agkistrodon Contortrix) In Southeastern Virginia, Christopher Edwin Petersen
Biological Sciences Theses & Dissertations
Radiotelemetry was used to study seasonal movement patterns, habitat use, and thermal relations of nine copperhead snakes, Agkistrodon contortrix, in southeastern Virginia from May 1993 to May 1995. Daily movements ranged from 0-450 m, with 0-5 m movements accounting for 65% of the observations. The seasonal movements of males were more extensive than those of females. Differences in seasonal movements between the sexes may be due to reproductive activity of the snakes. Both males and females significantly reduced their movements prior to shedding. More time was spent using upland deciduous forests than lowland river swamps or anthropogenic habitat. Copperheads …