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!

or more eggs/clutch several clutches/season All turtles lay eggs in soil

Female sea turtles come ashore at night to lay eggs - Why?

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?

See Figure for an astonishing movement from Brazil across the Atlantic to Ascension Island How do they do it? Olfaction? Magnetic orientation? Loggerhead trans-Pacific migration