A curious Evan Fox, 7, gently touched sea cucumbers and sea stars during a recent visit to the Waikiki Aquarium but his favorite encounter was with sea urchins.

“It’s so cool to touch it,” he said, as he excitedly explained how the prickly spines closed around his finger.

Evan was attending Critter Encounters with his grandmother, Ida Sagadraca of Pearl City, and younger brother Brennan, 5. The half-hour, behind-the-scenes sessions allow youngsters to interact with a variety of sea creatures while learning more about them.

Micah Bagley, 4, of Kaimuki, was intrigued with the hermit crabs. “It was crawling on my hand,” he said joyfully.

The families gathered around special display tables holding the marine animals and were allowed to feed miniature frozen shrimp to coral. Four-year-old Bailey Anderson giggled as she dropped the tiny shrimp from tweezers and enjoyed feeding seaweed to the urchins and tropical fish.

Mary Roney, community programs coordinator at the Waikiki Aquarium, leads Critter Encounters on Mondays. Private sessions are available to groups of five or more.

“Everyone comes with their own agenda so the class is tailored to the group,” she said. “We have locals who have lots of knowledge, visitors who are starting at ground zero or others who are working on a school project.”

This particular group had a lot of little ones so Roney focused on what the critters eat and whether they are velvety soft or prickly.

“I find that common Hawaiian reef creatures are still a mystery to many people even if they grow up here,” she said. For example, many don’t know that rock-boring sea urchins, found in tidepools and exposed reef flats, don’t sting, she explained.

“They don’t realize how crucial urchins are in keeping the reef ecosystem from getting smothered with seaweed. But after the kids feed the urchins, it clicks. They realize that those animals don’t just sit there. They use their teeth and mow the algae off of the reef.”

Learning about the marine environment and its inhabitants is the first step to getting people to care about it, according to Roney.

Critter Encounters are $5 per person, plus admission ($12 adults, $8 kamaaina and military, $5 ages 4-12 and 65 and older). Call 440-9011 or email reservations@waikikiaquarium.org.