Science News for Students: Parasite survives seal's deep dives

University of Cincinnati biologist Joshua Benoit explained to Science News for Students how a tiny parasite the size of a sesame seed can withstand the extreme atmospheric pressure of diving more than a mile below the ocean's surface with its host – an elephant seal.

Elephant seals are champion divers. They can hold their breath for more than 90 minutes while diving for food a mile deep. This depth would crush even many modern submarines. 

But not only do the seals survive the trip, but their parasites called seal lice do as well.

The Institute of Biology of Marine Organisms in Argentina put seal lice to the pressure test under lab conditions and found that most survived pressures equal to diving 6,500 feet.

Benoit told Science News for Students that it makes sense that lice that live on seals must be evolved to go where the seals go.

Benoit has studied other "extremophiles" in Antarctica. Extremophiles are creatures that live on the fringes of what's considered possible in extreme environments. Benoit's research found that a wingless fly in Antarctica cover their eggs in a kind of antifreeze to protect them from routine freezing and thawing.

Read the Science News for Students story.

Featured image at top: A northern elephant seal. Photo/Michael Miller