 The thin skin of the octopus accounts for a large portion of in-vitro oxygen uptake; estimates suggest around 41% of all oxygen absorption is through the skin when at rest.This number is affected by the activity of the animal – the oxygen uptake increases when the octopus is exercising due to its entire body being constantly exposed to water, but the total amount of oxygen absorption through skin is actually decreased to 33% as a result of the metabolic cost of swimming.When the animal is curled up after eating, its absorption through its skin can drop to 3% of its total oxygen uptake.