Pfaff, D. Hormonal regulation of synapses and cell number in adult canary brain and its relevance to theories of long-term memory storage. This has already been documented in some turtle species. Other species show disproportionately high female production at both high and low temperatures, with intermediate temperatures causing mostly male development.
Many species—such as several species of turtle and lizards, like the green iguana—have X and Y sex chromosomes again, like mammalswith females being "homogametic," that is, having two identical X chromosomes. Evolution of sex determination and the Y chromosome: SRY related sequences in marsupials.
Variations on this theme also exist. Why male garter snakes have small heads: The evolution and endocrine control of sexual dimorphism. Receptivity and 2-deoxyglucose uptake in female red-sided garter snakes submitted for publication.
We are finally beginning to understand the mechanisms by which this masterpiece is created. High levels of aromatase activity increase the production of female hormonesresulting in the development of female characteristics. As the Earth experiences climate change, increased temperatures could result in skewed and even lethal incubation conditions, which would impact turtle species and other reptiles.
PLOS One. Turtles of the World.
Psychobiology — The first attempts to understand sex-determination in mammals were made by removing the gonadal primordium in rabbit fetuses, resulting in all cases developing as females and therefore implying that the testicles were responsible for a male decision being made. Sex determination in Caenorhabditis and Drosophila in which the sex-determination signal depends on the relationship between the autosome and X chromosome dose is thus not comparable to what occurs in mice and most mammals where the presence of the Y chromosome leads to male development Wallis et al.