Study Finds Seals Sometimes Sleep on Ocean Floor

November 12, 2009

If you think your sleeping environment isn't perfect, try the bottom of the ocean. A recent study in the journal Biology Letters found that elephant seals while migrating from their breeding colonies in California to their wintering areas further north will roll over and sink to the seabed below for rest. A team of researchers tagged six juvenile elephant seals and released them 21 to 43 miles from their home at a reserve in California. Study co-author Russel Andrews told National Geographic, "Fortunately for us, as the seals swam back to the rookery, they performed the same kind of repetitive, deep-diving behavior that they do on their migrations across the Pacific." According to Andrews, the seals drift down to the ocean floor much like "a leaf that has dropped from a tree branch and is falling toward the ground." The researchers believe this fluttering motion keeps them from sinking too fast. They also note that diving to the bottom protects them from predators because few reside at those depths.

• Read the National Geographic article.
• Check out Animals' Sleep: Is There a Human Connection?