Twenty northern elephant seals wearing brand-new GPS satellite tags are swimming toward Alaska. UCSC doctoral student Jason Hassrick and his team of taggers will keep an eye on the seals' tracks on computers for 9 months, until they return to Año Nuevo State Reserve in February 2008.

The researchers want to know whether seals' physiological makeup or their age have any bearing on their feeding and diving abilities. Elephant seals are deep divers – the deepest recorded dive by the lab for a female seal is 4,800 feet (1600 meters) – and Hassrick wants to know if it's air capacity or diving experience that gives the seals their ability to dive so deep.

The seals live on Año Nuevo's beaches only about 10 weeks throughout the year – to breed in the winter months and to molt in the Spring and Summer . The researchers had to tag the seals after they molted to ensure that the tags stay on the seals, which meant they had three weeks to select and tag the seals.

After the seals return to Año Nuevo, the tagging team will scramble to retrieve the tags before the seals molt and the tags fall off. Then, the researchers will download the data from the tags, which gather information about their distribution at sea, their diving behavior and their physical environment.