This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Sea turtles are famous for being prodigious wanderers. Guided by Earth's magnetic field, ocean currents and the sun, they tend to crisscross the seas in search of food, returning to the region of their birth every few years to breed.
So when scientists discovered a population of sea turtles that appear to be very much homebodies, they were taken aback. "Here we show that 'yellow-morph' green sea turtles—one of two genetically distinct forms—occupy individual foraging areas that span one or more islands in the Galápagos. We expected them to migrate to distant beaches in the western Pacific to reproduce, yet interestingly, none of our satellite-tagged turtles even left the Galápagos Marine Reserve over the three years of our study," said Dr.
Rowe, a professor at Alma College in the United States and the corresponding author of a new study in Frontiers in Amphibian and Reptile Science. Green sea turtles are unique among the seven living species in being mainly vegetarian. Hatchlings start life as omnivores, but once fully grown, their diet consists of seagrasses and algae.
Yellow-morph green sea turtles roam the western Pacific Ocean's tropical and subtropical latitudes, while black morphs live in the eastern Pacific west of the Americas below Southern California. The only known waters in the world where these two coexist are around the Galápagos, where they intermingle and feed on the same species of marine plants. However, yellow morphs tend to grow faster than black morphs when young, which suggests that uncharacterized physiological differences do exist.
Rowe and colleagues set out to study the yellow morph's habitat preferences, range and movements between islands within the 198,000 square kilometers (76,400 square miles) of the Galápagos Marine Reserve. In 2015, they gently caught seven adult males and two adult females in the shallow waters off four islands. They gave them nicknames and fitted them with electronic tags that sent 'pings' to the low-orbit Argos satellite network.
The scientists tracked their charges for up to 418 days, typically until the tags fell off or stopped transmitting. Overall, the turtles preferred to stay in shallow coastal waters, although occasionally they ventured up to 25 kilometers (16 miles) offshore. Five of the nine animals stayed mostly in the vicinity of a single island during the study period, while Bernardo and Sara traveled between the islands of Isabela and San Cristóbal.
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