{"id":350,"date":"2025-08-14T09:35:03","date_gmt":"2025-08-14T16:35:03","guid":{"rendered":"https:\/\/scienceblog.com\/wildscience\/?p=350"},"modified":"2025-08-14T09:35:03","modified_gmt":"2025-08-14T16:35:03","slug":"river-otters-feast-in-filthy-spots-and-still-keep-the-bay-healthy","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/wildscience\/2025\/08\/14\/river-otters-feast-in-filthy-spots-and-still-keep-the-bay-healthy\/","title":{"rendered":"River Otters Feast in Filthy Spots and Still Keep the Bay Healthy"},"content":{"rendered":"

They dine where they defecate, swim where they hunt, and swallow prey crawling with parasites. North American river otters in Maryland\u2019s Chesapeake Bay<\/a> may not follow our hygiene rules, but their eating habits reveal a surprisingly important ecological role.<\/p>\n

In a new study published in Frontiers in Mammal Science<\/a>, Smithsonian Environmental Research Center<\/a> scientists offer the first detailed look at these otters\u2019 diets, latrine sites, and the parasites they consume\u2014showing how their feeding behavior could help maintain balance in local food webs.<\/p>\n

From Docks to Beaches, Otters Leave Clues in Scat<\/h2>\n

Elusive and mostly nocturnal, river otters are rarely spotted in the wild. Instead, researchers tracked them by locating \u201clatrines,\u201d shoreline sites where otters gather to eat, socialize, and leave scat. Over 11 months, the team identified 18 active latrines along the Rhode River near Edgewater, Maryland<\/a>. While many were on natural beaches and riverbanks, five turned up on manmade structures such as docks, boardwalks, and even shoreline staircases.<\/p>\n

\u201cIt is shocking how little information there is about their biology and ecology,\u201d said Katrina Lohan, co-author and head of SERC\u2019s Coastal Disease Ecology Lab<\/a>.<\/p><\/blockquote>\n

These sites were hotspots of otter activity, often marked by flattened vegetation, woody debris, and easy access to open water. Researchers collected 90 scat samples, using gloves and sterile tools to prevent contamination, then analyzed them under microscopes and with genetic metabarcoding techniques<\/a>.<\/p>\n

What\u2019s on the Menu? Fish, Crabs, and the Occasional Duck<\/h2>\n

DNA analysis revealed that finfish and crustaceans dominated the otter diet, making up 93 percent of all prey items. Blue crabs (Callinectes sapidus<\/em>)<\/a> and mummichogs (Fundulus heteroclitus<\/em>)<\/a> were among the top catches. Otters also dined on frogs, worms, and occasional birds, including ducks. Notably, they consumed two invasive species\u2014the common carp<\/a> and the southern white river crayfish<\/a>\u2014which could help curb their spread in the Bay.<\/p>\n