Marine Otter Diet and Feeding Habits

The marine otter is a member of the weasel family that inhabits areas along the western coasts and shorelines of South America. This type of otter should not be confused with the better known sea otter which only lives in North America. While less is generally known about the marine otter when compared to knowledge of other otter species, there is some documented information concerning its diet and feedings habits.


The diet of the marine otter primarily consists of a combination of crustaceans, fish and mollusks. The exact amounts of these primary constituents will vary depending on location as well as availability. Most small to medium prey that are carnivorous or omnivorous and live in the sub-tidal zone will be something that the marine otter would hunt if it had the opportunity. In addition to the three common dietary categories, the marine otter may also go after small mammals, birds, as well as fruits from local plants which are near the coast. On occasion, the marine otter may successfully hunt prey that is as large as its own anatomical dimensions, between thirty-two and forty-five inches (83 to 115 centimeters), or perhaps even larger.

The typical crustaceans that the marine otter feeds on include the local Chilean king crab which lives in the ocean and also freshwater prawns which are found in waterways near the coast. Mollusks that it feeds on include lapa, limpets, snail, octopus as well as cuttlefish. Most fish that the marine otter hunts are small to medium in size and are not usually longer than 24 inches (60 centimeters) long. Typical fish that may be part of the marine otter’s diet include: toad fish, clingfishes, damsel fish, whitemouth croaker, blennies, rock codling, and morwongs which are all indigenous to the South American habitat of this otter.


Like other otter species, the marine otters have a high metabolism and must spend much of their day hunting for food; as much as forty percent of total daylight hours. Peak activity for this otter usually occurs around 2pm but they are known to hunt as early as dawn. There are unfortunately no known studies or documentation on the nocturnal habits of the marine otter.

Hunting by the marine otter is usually done no more than fifteen hundred feet (five hundred meters) from the shoreline while and it does not usually hunt more than one hundred feet inland (thirty meters). Most of its hunting is done in the ocean around one thousand feet from shore (three hundred meters) and it dives for food along rocks where seaweed is present. For a yet unknown reason, the marine otter prefers a coastal habit that is rocky and with rough seas in order to forage in. This would be considered quite dangerous for any mammal as these areas usually have high winds and large swells but for some reason they do not hunt along sandy beaches or in calmer seas. This particular choice/habit is unique to the marine otter.

When in the water, small prey is often eaten while the otter is swimming or floating on its back, which is common for many otters. Larger prey is often brought to shore and eaten on the rocks. While some other otter species are known to use tools to get at their food (such as using rocks to break hard crustacean shells), no tool use has ever been documented for the marine otter so it is not known if they use the same methods. It is possible that they do know how to use tools like other otter species, but these activities have just not been seen by the low to moderate amount of observation and research done on these creatures.