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ELEPHANT SEALS - Divingambience: ocean Elephant Seals are able to make dives up to nearly a mile in depth. They can stay submerged for up to one and a half hours, and - they dive continuously for eight months at a time. I'm Jim Metzner, and this is the Pulse of the Planet. Till recently, scientists didn't know how elephant seals were able to perform their record-breaking dives, but now clues are beginning to emerge.Burney leBoeuf is a biology professor at the University of California in Santa Cruz.leBoeuf: There's a number of things that Elephant Seals do that enable them to dive long. They store most of the Oxygen that they require during a dive in blood, and they have a lot of blood - two and a half times more blood than we do. They lower their metabolic rate during the course of a dive. In that way they can parcel out this limited oxgyen supply over a long period of time, while they are finding and eating prey."Elephant seals also collapse their lungs before they dive deep.leBoeuf: Elephant seals exhale before they dive because air is compressable and under great pressure it would create a problem.The problem is what we humans call "the bends," which can be fatal.leBoeuf: The bends results when air under pressure causes Nitrogen to bubble up in the blood stream. Because the Elephant Seal does not dive with a lungful of air, this problem never comes up.On surfacing, the Elephant seal reinflates its lungs, to replenish its oxygen supply. Scientists are still trying to figure out how it does that - and does it quickly enough to enable another deep dive after spending just a few minutes on the surface. Part of the answer seems to be the seal's ability to store oxygen in its muscles. We've been listening to a program from our archives. If you want to hear more, check out our podcast. I'm Jim Metzner.