Learn More About Sea Turtles...
If you have read our previous posts about the Anna Maria Island, Florida Sea Turtles, you know we are passionate about helping save them from extinction.
Extinction: In biology and ecology, extinction is the cessation of existence of a species or group of taxa, reducing biodiversity. The moment of extinction is generally considered to be the death of the last individual of that species (although the capacity to breed and recover may have been lost before this point). Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively.
Sea turtles once populated our oceans by the millions, yet today many species of sea turtle are endangered and need our help!
We believe the more you know about sea turtles, the more able you are to help save them. We hope that you enjoy reading our posts about Florida's sea turtles... they truly are amazing. What follows are some of the most commonly asked questions about sea turtles.
Commonly Asked Questions About Sea Turtles
When do hatchling sea turtles emerge from their nests?
In the Southeast, hatchlings emerge in June, July, August, September and October.
Is it true the turles only emerge from the next when there is a full moon?
It is a myth that hatchlings emerge only around the time of a full moon. Hatchlings ready to emerge wait just beneath the sand surface until conditions become cool enough. This temperature cue prompts them to emerge primarily at night, although some have emerged in late afternoon or early morning.
When turtle hatchlings emerge from their nests, how do they (sea turtles) know where the Gulf is?
They have an inborn tendency to move in the brightest direction. On a beach, the brightest direction is most often the open view of the night sky over, and reflected by, the gulf. Turtle hatchlings also tend to move away from darkly silhouetted objects such as dunes and vegetation.
Are sea turtle shells hard or soft?
All species of sea turtle have a hard shell, or carapace, except for the leatherback sea turtle, which has a soft leathery carapace.
Do sea turtles have penises and vaginas?
Yes, similar to all other vertebrates male sea turtles have a penis and female sea turtles have a vagina. Both are internal organs located inside the tail. The penis is > 30 cm in length in male green turtles, and the hook at the end of the penis, adjacent to the sperm duct presumably assists in sperm transfer.
Both sexes have a cloaca, an opening on the tail that permits sexual intercourse, egg laying and removal of wastes. During mating, the male hooks his tail under the female (he has a claw like tip on the end of his tail) and then brings the cloacas together to allow entry of the penis into the females cloaca.
Very little is known about the mechanisms involved in mating and sperm transfer and these are areas of biology that warrant more investigation. Turtles have been seen mounted for over an hour, but it is impossible to tell whether intromission has occurred the whole time. For more information on the anatomy, please see the NOAA Guide to Sea Turtle Anatomy, by Dr Jeanette Wyneken. Answer courtesy of Mark Hamann, The World Conservation Union - Vietnam Office.
How do you tell a male from a female? And at what age?
In adult sea turtles males have a prominent tail that extends well beyond the carapace. It is more difficult to distinguish males from females in younger turtles. Some common methods that have been used are to use laparoscopy, a surgical technique, to directly view the gonads, or to measure the amount of testosterone in the blood (males have more).
How long have sea turtles been living on this earth?
Sea turttles appearared about 65 million years ago, by the same time that dinosaurs disappeared from earth. It is believed that they started life in the oceans, went onto land and then back to the water. They probably survived the cathastrophic fate of dinos by beeing in the water, although there are species of turttles known to have gone extinct at about those times.
The book The Biology of Sea Turttles by editors Peter L. Lutz and John A. Musik ( CRC Press, 1996) have the first chapter about evolution of these animals.
I brought home a small turtle (6'' diam shell), found washed up on the beach at Newcastle, NSW, AUSTRALIA.
Try contacting your local government wildlife agency or check the Online Directory of Sea Turtle Rescue, Treatment and Rehabilitation Organizations.
Is there a SPECIFIC temperature to determine whether the egg of a sea turtle is female?
For all sea turtles, the direction of sexual differentiation is dependent on sand temperatures during the middle third of incubation. Warmer sand temperatures produce more or all female hatchlings, and cooler sand temperatures produce more or all males. The pivotal temperature is the constant incubation temperature that produces equal numbers of male and female hatchling sea turtles. The transitional range of temperatures (TRT) is the range of temperatures that produces both sexes (for more details on these standardized definitions, see Mrosovsky and Pieau 1991). Only a handful of studies have determined the pivotal temperature and TRT for certain sea turtle populations.
So far, the pivotal temperature seems to be nearly always close to 29 °C or 82 °F (see Mrosovsky 1994 for more details). On the other hand, the TRT seems to vary quite a bit more. For example, leatherback sea turtles from French Guiana in South America have a transitional range of temperatures that span <0.75 °C or <1 °F, whereas green sea turtles from Suriname have a transitional range of temperature >3 °C or >6 °F (Mrosovsky et al. 1984; Chevalier et al. 1999). Because of the variability of the TRT in different sea turtle species and populations, and because we have studied incubation temperatures and sex ratio in only a few different populations, it is impossible to say what egg incubation temperature will absolutely produce a female sea turtle hatchling.
Probably, incubation temperatures greater than 33 °C or 91.4 °F are likely to produce only females, but it is not known for sure. There is an alternative, sure-fire way to produce female sea turtle hatchlings from developing eggs: simply place a drop of estrogen on the egg during the first half of incubation (Crews et al. 1994).
Sea Turtles spend there whole lives in the sea, but what do they drink for liquid intake?
All sea turtles drink only seawater all of their lives. They have special glands behind each eye, called "salt glands" that they use to get rid of all the salt from the seawater. When they drink the salt water the salt enters the blood and is transported to the salt glands that then produce a solution that contains about twice the concentration of salt as the seawater they drank. This concentrated solution comes out from the corner of the eye as salty tears and is washed away. In this way they can drink seawater, get rid of the salt in their tears and have about half the amount of seawater left as freshwater to use for their physical requirements. Other animals like sea birds and sea snakes can do this too, but sea turtles are the best at it.
What does a sea turtle look like?
Check the Sea Turtle Image Library at: http://www.seaturtle.org/imagelib/.
What is the genus and species of a sea turtle?
There are six genera and seven species of sea turtles.
- Chelonia mydas - green turtle
- Caretta caretta - loggerhead
- Eretmochelys imbricata - hawksbill
- Dermochelyis coriacea - leatherback
- Lepidochelys kempii - Kemp's ridley
- Lepidochelyis olivacea - Olive ridley
- Natator depressus - Flatback
What time of year do leatherback turtles lay their eggs, and where?
It depends on where you are in the world. Sea turtles tend to nest during the local summertime. In the northern hemisphere this would be May to August, and November to February in the sourthern hemisphere. As you approach the equator where there is no distinct summer nesting may occur year-round.
My neighbors' lights are visible from the beach. Why should I modify the lights on my beachfront property?
Sea turtles benefit from any reduction of artificial lighting on the nesting beach. As lighting is reduced, hatchlings will have a better chance of reaching the sea.
How bright can a light be without affecting hatchlings or sea turtles on the beach?
Unfortunately, no simple measure of light intensity can reveal whether a light source is a problem. Any light that is visible from the beach is likely to cause problems.
Will placing bright lights on platforms offshore guide hatchlings into the water off lighted beaches?
Apart from being overly expensive and complicated, lighting the gulf to draw hatchlings offshore probably would create more problems, such as interfering with hatchling dispersal and making the babies more vulnerable to predatory fish.
How expensive is a beach-darkening program?
The simplest solution, turning off lights visible from the beach during the nesting season, costs little or nothing and may actually save electricity costs. Most of the essential lighting that remains can be easily shielded so that the light performs its intended function without reaching the beach. Proper shields can be made from inexpensive metal flashing and fastened with screws.
Replacing fixtures is more expensive but is necessary only when an owner is concerned about lighting efficiency or aesthetics. Choosing well-designed fixtures and incorporating light-management techniques into the plans for coastal development are the most effective ways to fulfill lighting needs while protecting sea turtles.
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