BRISTOL, R.I. – A rare blue lobster kept at the Audubon Society of Rhode Island has just molted, revealing an intensely hued bright blue shell.

The female lobster molted last month, said Anne DiMonti, co-director of education for the group. Growing lobsters lose their shells periodically through molting, when the old thick shell is replaced by a new one.

“When lobsters go through a molt, their new shell underneath, well, it’s new. It’s like a new pair of shoes. It’s bright and shiny,” DiMonti said.

DiMonti said the blue color will become less intense as the lobster’s shell thickens and gets heavier.

Molting generally happens about 25 times in the first 5 to 7 years of life, according to the Audubon Society. After that, the crustacean might only molt once a year.

DiMonti said the lobster, thought to be about 8 years old, was donated in the summer of 2003 by Tom Wallis, a Barrington fisherman who caught it in Narragansett Bay. It is the second blue lobster Wallis has donated to the Audubon Society, and the third one he has caught in his career, DiMonti said.

Earlier this year, scientists at Bowdoin College and the University of Connecticut said they believed a genetic defect in some lobsters produces an excessive protein that forms a blue color in the shells of roughly one in a million lobsters.