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Explore the fascinating world of long-lived turtles, from their thermal constraints to reproductive behaviors. Learn about their unique characteristics, diet preferences, and nesting habits. Discover the conservation challenges they face and potential solutions like captive breeding. Delve into the remarkable trans-Pacific migration of Loggerhead sea turtles and the mysteries behind their navigation abilities.
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Long -lived Thermal constraints Surface area:volume Small - bask Left-right shunt! Large Size (8’ long leatherback!) Thermal inertia 37 degree BT in 29 deg water Counter-current exchange of heat in flippers
Most aquatic and sea turtles carnivorous (jellyfish, sponges, molluscs) Terrestrial tortoises often herbivorous Green Sea turtle herbivorous - sea grass
Mating - Males have penis - internal fertilization Tortoises call to attract mates, male-male fights All turtles Oviparous!
All turtles lay eggs in soil 10- 100 or more eggs/clutch several clutches/season
Female sea turtles come ashore at night to lay eggs - Why?
28-130 day incubation Group needed to dig out and to survive race Race for the sea Often at night Orient by 1) light, 2) wave motion 3) magnetic Exercise & imprinting
TDS (Temperature Dependent Sex Determination) Fig 10-9 % Male Loggerhead sea turtles at different temperatures
Young turtles drift with plankton, probably join currents in Atlantic Conservation challenges: Long Life, low repro, slow devpt Loss of breeding sites, harvest, development Captive breeding? Helping young to water to avoid predators?
Loggerhead trans-Pacific migration See Figure 10-11 for an astonishing movement from Brazil across the Atlantic to Ascension Island How do they do it? Olfaction? Magnetic orientation?