Northern Elephant Seals
Nature’s power nappers
Last week, while the TND fam were preparing for our latest get together, the New York Times’ Trilobites section, dedicated to unearthing fascinating morsels of science, hit the mark when it profiled the northern elephant seal.
My diligent research reveals that elephant seals are large, carnivorous earless seals. They weigh up to 11k pounds and measure up to 13 feet long — smaller than elephants, who typically sleep around two hours per day. Like humans, elephant seals completely shut their minds down when they sleep. Unlike (most) humans, they typically sleep only two hours per day, often in ~10-minute increments — that is, while they’re out gorging (when at sea to breed and molt, where they don’t eat, they sleep around 10 hours per day). They take these power naps as far as as 2500 feet below the ocean’s surface to protect themselves from predators.
Northern elephant seals experience sleep cycles not unlike humans, including REM sleep while they flip upside down and gently go deeper as they spin in circles. It’s not clear to me how the timing and length of these sleep cycles compare with those of humans, given that our sleep cycles typically last 90 minutes.
I wonder if northern elephant seals ever have trouble falling asleep or staying asleep, wrestling with how long or how late to nap. I wonder if there is a northern elephant seal equivalent of TND or TAENR. I wonder if we’ll ever have a NES guest writer on TND some day. I wonder.