FactSlap
The secret life of otters and their rocks.
Otters don’t just swim, hunt, and float. Some of them carry lifelong attachments — to rocks.
Here’s a pocketful of strange, stone-cold facts about one of the animal kingdom’s quietest love affairs:
• Sea otters are among the few non-primate species known to use tools — most often rocks to crack open hard-shelled prey.
• They have loose pouches of skin under their forearms, used to stash prized rocks and snacks.
• Some otters carry the same “lucky” rock for years — sometimes for life.
• Young otters don’t instinctively use tools; they learn by watching their mothers.
• Otters show preferences for certain rocks — usually flat, easy to grip, and rough enough to hold slippery prey.
• In parts of California and Alaska, researchers have found “anvil” stones reused by generations of otters — forming little otter dining stations.
• Otters have been seen tossing, juggling, and playing with rocks — behavior that likely hones their dexterity.
• Studies suggest stone use gives otters a survival edge, helping them access food few others can.
• One long-observed female sea otter in Monterey Bay used the same rock for at least five years.
• Not all otters use tools — the behavior is more common in sea otters than in river otters, and more frequent in certain regions and populations.
