Sea Turtle Hatchlings
See if you can guess the species below! (answers at the bottom of the page)
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The sex of hatchlings is influenced by the temperatures during the middle-third of embryonic development (as the eggs are incubating in the clutch) - this is called Temperature Dependent Sex Determination (TSD) and is common in reptiles. Warmer temperatures typically produce females in sea turtles, and cool temperatures produce males. The pivotal temperature is the incubation temperature that produces equal numbers of males and females. Recent research suggests that other environmental factors may be at play in TSD (e.g., rainfall) and that the pivotal temperature varies by geographic location and species.
Unlike mammals, sea turtles don’t have sex chromosomes (no X or Y). How can we tell if a sea turtle is female or male? In adults, it’s relatively easy—a male has a long tail that extends well beyond the carapace. In comparison, a female has a short tail. With hatchling, juvenile, and sub-adult sea turtles, it’s not possible to determine their sex simply by looking at them; they are not sexually dimorphic, meaning that they do not have any external features to distinguish males from females. The exact mechanism for sex determination is unknown.
1 - Loggerhead
2 - Leatherback
3 - Green
4 - Green
5 - Leatherback
6 - Leatherback
7 - Loggerhead
8 - Leatherback