As of 2014, the exact lifespan of a lobster is unknown, but scientists have estimated that a European lobster's lifespan averages 31 years for males and 54 years for females. Scientists obtained these estimates by measuring fat deposits in the creatures' eyestalks.
Contrary to popular belief, lobsters are not immortal. Most decapod crustaceans do not have a maximum size limit, and they continue to grow until death. When lobsters molt, they grow larger. An average lobster can molt up to 44 times before it's a year old, but as lobsters age, the rate of molting slows down. Lobsters that are near the end of their lifespan stop molting completely, which leaves them susceptible to various infections and diseases from bacteria.