Seahorses. Plus if Jurassic park is to be believed, some frogs. Oh! And hyenas. (Seriously.)
- Gators, crocodiles. That's is why conservatives dont believe climate change. They want trans animals. On the other hand, leftists are transphobics, and want to combate natural sex-change!
Rising temperatures could force the birth of more female crocodiles and fewer males, an expert said today. The scenario could cause some croc populations to disappear. Crocodile gender is determined by temperature during incubation. Nest temperatures of 89.6 to 91.4 degrees Fahrenheit (32-33 Celsius) result in males.
https://www.livescience.com/1154-global-warming-doom-male-crocodiles.html#:~:text=Rising temperatures could force the,33 Celsius) result in males.
Warming climate could cause a sex imbalance in crocodiles making it more difficult to find mates, according to a south African scientist.
Dr. Alison Leslie, a prefessor at South Africa’s University of Stellenbosch, said that crocodile gender is determined by embryo temperature during incubation and that higher temperatures could skew the sex ratio of populations.
“A difference of 0.5 – 1ºC in incubation temperature results in markedly different sex ratios,” said Leslie, principal investigator of the ‘Crocodiles of the Okavango Delta’ project organized by the Earthwatch Institute, a global volunteer organization that supports scientific field research by offering members of the public opportunities to work alongside leading field scientists and researchers. “Research shows that nest temperatures of about 32-33 degrees Celsius result in males, while temperatures higher and lower result in females. Temperatures within a nest can vary from the top to the bottom of the nest, and can result in mixed-gender hatchlings. ”
“More female hatchlings due to the cooler or hotter incubation temperatures could lead to eventual extirpation of the species from an area,” added Leslie. “Even though crocodilians have been around for millions of years, and as important as these creatures may be in the systems they occupy, they are a much understudied species,”
https://news.mongabay.com/2006/11/climate-change-could-cause-sex-switch-in-crocs/
Global warming may cause sex changes in lizards
By
Rachel Feltman
According to new research, climate change may leave some lizards in a gender lurch. The Australian bearded dragon's sex is determined by both its chromosomes and the environment its egg is incubated in, so warmer temperatures could be skewing wild populations to have more females.
In a
study published Wednesday in Nature, researchers report that they've seen evidence of this in wild populations of
Pogona vitticeps.
"This is the first time we have proved that sex reversal happens in the wild in any reptile at all," lead study author
Clare Holleley of the University of Canberra
told the Associated Press. The study, she said, is an example of how climate extremes can put animals at risk on the most basic biological level.
It's normal for some of these lizards to hatch as females when they have the chromosomal makeup of males. That's because the species doesn't rely solely on chromosomes to determine their sex.
The lizards are also influenced by the temperature at which their eggs are incubated. Some species use just chromosomes or just egg temperature to determine their sex (and no one is really sure why), but the bearded dragon uses a combination of both.
With temperatures warming, however, this mechanism may end up putting the lizards at a disadvantage.
In the new study, Holleley and her colleagues combined controlled breeding experiments with field data collected from observations of 131 adult lizards.
In warmer areas, 11 of the wild lizards were found to be females with male chromosomes -- indicating that temperature had determined their fate.
Eleven isn't a lot, and the researchers plan on continuing their research with larger sample sizes. But here's the potential problem: When those females reproduced -- which they did at nearly twice the rate of chromosomal females -- their offspring all lacked sex chromosomes, meaning that their sex was determined entirely by temperature.
So in a warming climate, it's possible that the species could see a snowball effect of females primed to produce female offspring, spurring a growing sex imbalance. Sure enough, the researchers saw the percentage of heat-determined females going up each year of their study. Eventually, there could be so few males that the species would lack the genetic diversity needed to stay strong in the face of their warming world.
It wouldn't be impossible for the male sex chromosome to disappear entirely, according to the researchers.
@Zookeeper Gabe
https://www.washingtonpost.com/news...bal-warming-may-cause-sex-changes-in-lizards/