How do you find out the age of a lobster? Count its rings—just like a tree.

There's evidence lobsters and trees are more alike than they may appear on the outside.

Lobsters, pictured at a Maine processing plant in 2014 (left), and a tree stump (right). Robert F. Bukaty / AP, Wikimedia Commons

Wondering about the age of the huge lobster you just caught?

Typically, fisherman and scientists have relied on the unscientific method of estimating the crustacean’s age based on its size (after all, they really do never stop growing until they die, which could take awhile).

However, Maine scientists are hoping to validate findings that suggest there is another way.

As the Associated Press reported in 2012, Dr. Raouf Kilada, of the University of New Brunswick, found lobsters have growth rings — just like that of a tree — inside their stomachs. And now Dr. Rick Wahle and graduate student Carl Huntsberger, both of the University of Maine, are testing a new technique to validate those findings.


Per the university’s Darling Marine Center:

Kilada found tree-ring like microscopic bands, less than 1 millimeter thick, within the gastric mill of lobsters and crabs, a part of the stomach that grinds up food. He is now working with labs like the Darling Marine Center to validate that they do indeed show annual growth.

Since lobsters molt (i.e. shed their shells), any exterior signs of growth bands are discarded with the rest of their exoskeleton. Not knowing a lobster’s true age has been a problem for those trying to measure the animal’s health and stock sustainability, according to the center.

Huntsberger says they will dissect lobsters held in captivity over the course of three years.

According to Huntsberger, there’s preliminary data showing that the bands, which will be studied under a microscope, show annual growth patterns.