Mike Szydlowski| Columbia Daily Tribune

The Earth is warming. There is no doubt about that.

With that warming comes melting glaciers, sea level increases, stronger storms and now, lots of female sea turtles!

What?Thats right:another strange consequence of climate change is that the male/female ratio of some animals is becoming skewed at an alarming rate.Buthow does this happen?

In most animals, the gender of the animal is determined by genetics passed down by parents. However, in some fish and reptiles, the temperature during a very specific time duringincubationdetermines the gender.Sea turtles are just one species where gender is controlled by temperature.

In sea turtles, that very specific time of sex determination is during the middle third of the incubation period. With the sea turtle incubation period being about 60 days, the temperature of the egg during days 20-40 determines the gender of the turtle hatchling.

Scientists say if the egg is below about 82 degrees Fahrenheit during days 20-40, the turtle will hatch as a male. If it is above about 88 degrees, it will come out female. In between those temperatures, the gender could go either way.

Scientists at a Florida turtle sanctuary reported they have seen almost no male sea turtlehatchlings in the last four years. Those four years have also been the hottest four years on record on the beaches where the sea turtles lay their eggs.

Scientists studying sea turtles in Australia have found the very same circumstance. In that case, 99% of all turtle hatchlings were female. The changing climate has caused the sandy nests to constantly stay above the critical 88 degrees Fahrenheit.

Scientists have found it isn't just turtles being affected by climate change. A recent study found some species of bearded dragons are also shifting to disproportionally female populations due to the rising temperatures.Other studies have found the same thing happening to some species of fish.

Obviously, a population of sea turtles that is 99% female is not a great thing for the future. There is no doubt this is troubling for populations of sea turtles that are already struggling from habitat loss. There is no good news in this scenario, but there are some other circumstances that offer hope.

First, in the animal world, males can fertilize quite a few females. While bad, the mostly-female scenario we have now is better than a mostly-male scenario. The population would still suffer, but maybe not quite as much as one would think.

Second, not all populations of sea turtles are experiencing this phenomenon. Some populations are in regions that are warming, but not as drastically as in other places. This is not good news for the Florida or Australia turtle populations, but could mean other populations remain more stable.

Third, it is possible over time that sea turtles will migrate to cooler waters farther north. This would solve that problem.However, the adult turtles do not know there is a problem, so there really is no reason for them to migrate.

Some have suggested humans relocate some turtle populations farther north. While this could help, there are countless examples of negative things that occur when you move a species into a new ecosystem to solve a problem.That solution often causes other problems.

While this is sad for the sea turtles future, does it really impact humans? It does! What humans are just now starting to realize(scientists have always known this) is that everything in the plant and animal world is connected. Humans are part of that world, and every change ends up impacting us in some way.

Lets hope for some cooler weather for our nesting sea turtle eggs.

Mike Szydlowski is a science teacher and zoo facilitator at Jefferson STEAM School.

TIME FOR A POP QUIZ

1.What is temperature-dependent sex determination?

2.What types of animals have genders that are determined by the temperature?

3.Why is it unlikely that female turtles will travel north to lay eggs in cooler areas?

4. While still bad, why is a mostly-female population better than a mostly-male population?

5.What is one strategy that humans could try to help this problem?

LAST WEEKS POP QUIZ ANSWERS

1.What is a hellstrip?

A hellstrip is a nickname for the strip of grass between the street and the sidewalk. It was given this name because of how much abuse this area receives.

2.What are the benefits to planting trees in your yard?

Trees provide habitat for our important species, cool your yard and house in the summer, and increase the value of your home.They also make your home look much better.

3.While trees feed caterpillars, what needs to be done to help them to turn into butterflies and moths?

Most caterpillars burrow into soil to pupate and turn into butterflies and moths. Our lawns are not easy to burrow into. Turning the areas below trees into native areas will help them complete their lifecycle.

4.Why is the soil below our lawns often difficult to dig into?

Lawns have very shallow roots (which is why they dry out so quickly). The shallow roots do not break up the soil the way native plants would.

5.Why would people want to save insects? Dont we try to get rid of them?

Insects support all life on Earth.If insects continue to disappear, so will humans. Most insects do not cause any issues for humans.

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Why a warming Earth affects the gender ratio of sea turtles - Columbia Daily Tribune

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