Global heating means almost every sea turtle in Florida now born female | Hacker News Reader

Global heating means almost every sea turtle in Florida now born female

theguardian.com

32 pointstpc37 comments

Temperature based sex determination was new to me, so I went searching for more information. This book chapter describes the mechanism:

https://www.ncbi.nlm.nih.gov/books/NBK9989/

But left me wondering what the advantage of such mechanisms might be. Elsewhere in the same book they state:

"One advantage is that it probably gives the species the benefits of sexual reproduction without tying the species to a 1:1 sex ratio. In crocodiles, in which temperature extremes produce females while moderate temperatures produce males, the sex ratio may be as great as 10 females to each male (Woodward and Murray 1993). The major disadvantage of temperature-dependent sex determination may be its narrowing of the temperature limits within which a species can exist. This means that thermal pollution (either locally or due to global warming) could conceivably eliminate a species in a given area (Janzen and Paukstis 1991).

Ferguson and Joanen (1982) speculate that dinosaurs may have had temperature-dependent sex determination and that their sudden demise may have been caused by a slight change in temperature that created conditions wherein only males or only females hatched from their eggs."

In most cases one sex has more phenotypic variation, conferring greater survivability of the species in changing environments.

In humans and most mammals it's males. But in nature sex is much more complex.

I don't know a lot about reptiles. But perhaps this female swing will be ultimately good for them over time.

I wonder if we are looking at it from the wrong point of view, yes the environment is warmer but that should be an advantage to reptiles. It would make sense that all the turtles would be more active in a warmer environment including their reproductive activities. Less but more active males plus more females equals more reproduction of the species. No?

A minor problem for the loggerhead, but a potentially big problem for Lepidochelys kempii, critically endangered that basically only breeds in Tamaulipas and Texas.

Does anyone where have personal experience with this? Sounds like a fascinating subject.

I walk on a nesting sea turtle beach each morning here in Florida and chat up the local researchers who pass by daily. There are around 300 nests in the 1/2 mile zone I walk, with around 100 eggs per nest. Every few feet there’s a yellow wooden marker in the sand indicating a nest. They’re just starting to hatch now and yes, it’s adorable. I’m not an expert by any means, but take an interest and have some personal experience if you have any basic questions!

Is the population of sea turtles falling fast? It sounds like this wouldn’t last more than a generation or two.

But I’ve also been told that - in humans - fertility rate is dependent on the number of females not males.

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