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Gordon M Burghardt

Publications and source records attributed to Gordon M Burghardt.

6 recordsLinked to original sources
PubMed2006

Post-glacial recolonization of the Great Lakes region by the common gartersnake (Thamnophis sirtalis) inferred from mtDNA sequences.

Pleistocene events played an important role in the differentiation of North American vertebrate populations. Michigan, in particular, and the Great Lakes region, in general, were greatly influenced by the last glaciation. While several hypotheses regarding the recolonization of this region have been advanced, none have been strongly supported. We generated 148 complete ND2 mitochondrial DNA (mtDNA) sequences from common gartersnake (Thamnophis sirtalis) populations throughout the Great Lakes region to evaluate phylogeographic patterns and population structure and to determine whether the distribution of haplotypic variants is related to the post-Pleistocene retreat of the Wisconsinan glacier. The common gartersnake was utilized, as it is believed to have been one of the primary vertebrate invaders of the Great Lakes region following the most recent period of glacial retreat and because it has been a model species for a variety of evolutionary, ecological, behavioral, and physiological studies. Several genetically distinct evolutionary lineages were supported by both genealogical and molecular population genetic analyses, although to different degrees. The geographic distribution of the majority of these lineages is interpreted as reflecting post-glacial recolonization dynamics during the late Pleistocene. These findings generally support previous hypotheses of range expansion in this region.

Animals↗
PubMed2006

Editorial: Journal of Comparative Psychology.

Both continuity and change typically mark the changing of editors at a long-established journal with extended editorial terms. Change is inherent in any dynamic field and is independent of editorship, but editors have an influence that should be wielded in a fair, responsible, judicious, and scientifically rigorous manner, while inevitably reflecting their own perspectives and values. The Journal of Comparative Psychology will continue to publish exciting, fascinating, assessable, controversial, and well-written reports on research, be the topic traditional, interdisciplinary, applied, or one breaking risky new ground. Editorial standards must be high, but appropriate for various subfields, and as editor the author will try to make those judgments carefully. The author would also like to see more submissions of brief reports describing exciting developments as well as submissions on significant theoretical, conceptual, and methodological issues during his tenure as editor.

Humans↗
PubMed2006

Environmental enrichment alters the behavioral profile of ratsnakes (Elaphe).

This study investigated the effects of environmentally enriched and standard laboratory housing conditions on behavioral performance in 16 subadult ratsnakes (Elaphe obsoleta) using a split-clutch design. In a problem-solving task, snakes housed in enriched environments (EC) exhibited shorter latencies to the goal hole as compared to snakes housed in standard conditions (SC). In an open field task, EC snakes tended to habituate more quickly than SC snakes with repeated testing. A feeding task did not reveal any significant differences between EC and SC snakes. A discriminant function analysis correctly assigned all snakes to their appropriate housing treatment groups, based on the responses in each of the behavioral tasks. This suggests that each group had a distinct behavioral profile; that is, EC snakes were more behaviorally adaptive than SC snakes. This study demonstrated that housing conditions can affect the behavior of captive snakes and produce improvements in behavior similar to those seen in mammalian enrichment studies.

Animals↗
PubMed2005

Unlearned appetite controls: watersnakes (Nerodia) take smaller meals when they have the choice.

Studies of appetite in mammals emphasize that meal size is learned, but lactation and parental care constrain testing of naive individuals. Neonatal reptiles, in contrast, are self-sufficient foragers. The authors examined the effect of prey size on meal size in primivorous (at first feeding) northern watersnakes (Nerodia sipedon). When offered an excess of small prey (2%-20% of snake mass), neonates ate significantly smaller meals (M = 23.5% of snake mass) than when offered a single huge item (range = 32%-55%). The authors conclude that (a) the taking of smaller meals is not a learned effect, (b) there may be a satiety threshold for meal size rather than a target, (c) oropharyngeal stimuli may provide satiety cues, and (d) huge meals may have fitness costs.

Age Factors↗
PubMed2005

Snake mating systems, behavior, and evolution: the revisionary implications of recent findings.

Sexual selection and mating systems profoundly influence the behavior and psychology of animals. Using their own studies of green anacondas (Eunectes murinus) and reviewing other recent studies, the authors conclude that incomplete data derived from a few well-studied snake species have led to general acceptance of polygyny as the dominant mating system in snakes. New data on behavior, paternity, and life history in a diverse taxonomic array of snakes support the view that polyandry is not only common in snakes but may have been the ancestral mating system. This interpretation helps to explain many seemingly paradoxical behavioral differences between lizards and snakes, such as the lack of territorial systems in most snakes and their frequent female-biased sexual size dimorphism.

Animals↗