THE ANIMAL FILES

Sea otter

Enhydra lutris

A sea otter can carry a meal back up in a fold of skin.

Sea otters forage underwater and often eat while floating on their backs. Forepaws handle prey, skin pouches store collected food, and some individuals use stones to open hard shells. Grooming and feeding both occupy important parts of the day.[1]

Follow the evidence ↓
Sea otter
Image: Mike Baird from Morro Bay, USA · Commons · CC BY 2.0
Food storage
Loose skin pouches beneath the forelegs[1]
Tools
Stones can help open shellfish[1]
Ecosystem link
Predation on urchins can benefit kelp[1]

From seabed to floating table

Sea otters lift rocks, dig for clams and collect prey on dives. A loose skin pouch beneath a foreleg can hold food until surfacing. At the surface, the paws bring food to the mouth while the animal floats on its back. Stones may serve as a surface against which hard-shelled prey is struck.[1]

Grooming is a daily job

Grooming includes cleaning fur, removing loose hairs, untangling knots and working air into the coat. Frequent rubbing and rolling need not be interpreted as parasite removal alone. Feeding can leave scraps in the fur, and rolling in water also helps clear them. The animal actively maintains the condition of the coat between foraging bouts.[1]

A predator’s indirect effect

Urchins graze kelp, and otters can reduce that grazing by eating urchins. This creates an indirect benefit for kelp habitat. The relationship varies: some kelp forests persist without otters because other factors control urchins. “Keystone species” describes a strong ecological influence, not a rule that every healthy kelp bed must contain otters.[1]

A COMMON MIX-UP

Must every kelp forest have sea otters to survive?

No. Otters can strongly affect urchin grazing, but other controls also operate in some systems.[1]

TRY A LITTLE REASONING

How can eating an animal indirectly help a plant-like organism?

Reveal the explanation

Eating urchins reduces their grazing pressure on kelp, connecting predator, herbivore and habitat.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Enhydra lutris (adapted and translated; exact revision)
  2. NCBI Taxonomy — Enhydra lutris (identity and game lineage)

Last fact check:

One discovery leads to another

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