SpeciesFacts

All species › Mammals › Sea Otter

Sea Otter

Enhydra lutris

Mammal · family Mustelidae · order Carnivora

  1. G1
    Critically imperiled
  2. G2
    Imperiled
  3. G3
    Vulnerable
  4. G4
    Apparently secure
  5. G5
    Secure

NatureServe global rank G4: apparently secure[2].

Updated October 30, 2026. Published by Humblebee.

Sea Otter
Photo: Mike Baird from Morro Bay, USA, CC BY 2.0, via Wikimedia Commons.
Endangered Species Act
Not listed[1]
NatureServe global rank
G4 Apparently Secure[2]
Native in
3 states[3]
Longest recorded life
27 years[4]

The sea otter (Enhydra lutris) is a mammal in the weasel family, Mustelidae[5]. It is not listed under the US Endangered Species Act[1], and NatureServe records it as native along the coasts of Alaska, California and Washington[3].

Conservation status

Sea otters are not listed as endangered or threatened under the US Endangered Species Act[1]. NatureServe ranks the species G4, Apparently Secure, worldwide[2] and N4, Apparently Secure, in the United States[6]. The IUCN Red List category recorded by NatureServe is Endangered[7]. The species is also on CITES Appendix II, which means its international trade is controlled[8].

Status Value
Endangered Species Act[1] Not listed
NatureServe global rank[2] G4 (Apparently Secure)
NatureServe US rank[6] N4 (Apparently Secure)
IUCN Red List (via NatureServe)[7] Endangered
CITES (international trade)[8] Appendix II
Total population (NatureServe estimate)[9] 10,000 to >1,000,000 individuals

Where Sea Otter lives

NatureServe lists the sea otter as native in 3 US states: Alaska, California and Washington[3]. It is ranked as possibly gone from Oregon[10]. NatureServe gives each state its own rank, shown in the table on this page[11]. The Washington group began with 59 otters moved from Alaska in 1969 to 1970, and a spring 1996 count found 430[12].

Alaska: native, state rank S4AKMaine: not recordedMEWisconsin: not recordedWIVermont: not recordedVTNew Hampshire: not recordedNHWashington: native, state rank S2WAIdaho: not recordedIDMontana: not recordedMTNorth Dakota: not recordedNDMinnesota: not recordedMNIllinois: not recordedILMichigan: not recordedMINew York: not recordedNYMassachusetts: not recordedMAOregon: extirpated or possibly extirpated, state rank SHORNevada: not recordedNVWyoming: not recordedWYSouth Dakota: not recordedSDIowa: not recordedIAIndiana: not recordedINOhio: not recordedOHPennsylvania: not recordedPANew Jersey: not recordedNJConnecticut: not recordedCTRhode Island: not recordedRICalifornia: native, state rank SNRCAUtah: not recordedUTColorado: not recordedCONebraska: not recordedNEMissouri: not recordedMOKentucky: not recordedKYWest Virginia: not recordedWVVirginia: not recordedVAMaryland: not recordedMDDelaware: not recordedDEArizona: not recordedAZNew Mexico: not recordedNMKansas: not recordedKSArkansas: not recordedARTennessee: not recordedTNNorth Carolina: not recordedNCSouth Carolina: not recordedSCDistrict of Columbia: not recordedDCOklahoma: not recordedOKLouisiana: not recordedLAMississippi: not recordedMSAlabama: not recordedALGeorgia: not recordedGAHawaii: not recordedHITexas: not recordedTXFlorida: not recordedFLPuerto Rico: not recordedPR
State presence as recorded by NatureServe[11].
Show state ranks (4 states)
StateRankMeaning
AlaskaS4Apparently Secure
CaliforniaSNRNot Ranked
OregonSHPossibly Extirpated
WashingtonS2Imperiled

Habitat

Sea otters live in bays and sounds, along tidal flats and shores, and in near shore waters[13]. They tend to stay within about 2 km of land, in shallow water with kelp forests and plenty of shellfish[14]. When the weather turns rough, they shelter in kelp or in sheltered coves[14]. In Alaska they often come out onto land, while in California they rarely do[14].

Habitat types recorded by NatureServe[13]

Size, diet and lifespan

Sea otters eat both fish and invertebrates, animals without a backbone[15], with one estimate putting the diet at 50% invertebrates and 50% fish[16]. Sea urchins, crabs and shellfish are key foods, and an otter may use a rock as a tool to crack open hard shells[17]. A typical adult is about 150 cm (59 in) long[18] and weighs about 35 kg (77 lb)[19]. A mother usually has 1 young at a time[20]. Gestation, the time a baby grows inside its mother, is about 140 days[21]. Females can first breed at about 974 days old[22]. The longest recorded lifespan is 27 years, in captivity[4].

Trait Value
Typical length[18] 150 cm (59 in)
Typical adult weight[19] 35 kg (77 lb)
Longest recorded lifespan (AnAge)[4] 27 years (captivity)
Litter or clutch size[20] 1
Gestation or incubation[21] 140 days
Female maturity[22] 974 days (about 2.7 years)
Food habits[15] Piscivore, Invertivore
Active[23] crepuscular, diurnal
Migration[24] non-migrant, local migrant

Estimated diet composition (EltonTraits 1.0)[16]

  • 50% invertebrates
  • 50% fish

When to look for it

Sea otters feed during both day and night, resting between meals[25][26]. Most stay in one area, though some move locally with the seasons[24][27]. Young are born mostly in early summer in Alaska and in late winter in California[28]. People report the most sightings on GBIF in May, June and July[29].

January: 1,258 recordsJanFebruary: 1,345 recordsFebMarch: 1,694 recordsMarApril: 2,318 recordsAprMay: 2,636 recordsMayJune: 2,928 recordsJunJuly: 3,091 recordsJulAugust: 2,266 recordsAugSeptember: 1,887 recordsSepOctober: 1,523 recordsOctNovember: 1,445 recordsNovDecember: 985 recordsDec
US observation records on GBIF by month, all years. The three months with the most records are highlighted. Records show when people look and report, not how many animals there are[29].
Show records by month
MonthRecords
January1,258
February1,345
March1,694
April2,318
May2,636
June2,928
July3,091
August2,266
September1,887
October1,523
November1,445
December985

Where to see it

National Park Service species lists record Sea Otter as present in 5 park units[30]. Present means the park has a confirmed record, not that sightings are common.

States with the most GBIF observation records: California, Alaska, Washington, Oregon, Hawaii[31]. These counts follow where people look and report, not population size.

Questions people ask

Is the sea otter endangered?
Sea otters are not listed under the US Endangered Species Act[1]. The IUCN Red List category recorded by NatureServe is Endangered[7], while NatureServe ranks them G4, Apparently Secure[2].
Where do sea otters live in the US?
NatureServe lists them as native in Alaska, California and Washington[3]. They are ranked as possibly gone from Oregon[10].
What do sea otters eat?
They eat invertebrates and fish, estimated at 50% each[16]. Sea urchins, crabs and shellfish are main foods[17].
How big is a sea otter?
A typical adult is about 150 cm (59 in) long[18] and weighs about 35 kg (77 lb)[19].
How long do sea otters live?
The oldest known sea otter in AnAge lived 27 years in captivity[4]. This is a record, not a typical lifespan[4].

Facts and sources

  1. Sea Otter is not listed as endangered or threatened under the US Endangered Species Act in USFWS ECOS data (checked 2026-10-30). USFWS ECOS
  2. NatureServe global conservation status rank for Sea Otter: G4 (Apparently Secure). NatureServe Explorer
  3. NatureServe lists Sea Otter as native in 3 US states and territories: Alaska, California, Washington. NatureServe Explorer
  4. Maximum recorded lifespan in AnAge: 27 years in captivity. This is a record, not a typical lifespan. AnAge
  5. Sea Otter (Enhydra lutris) is a mammal in the family Mustelidae, order Carnivora. NatureServe Explorer
  6. NatureServe national rank in the United States: N4 (Apparently Secure). NatureServe Explorer
  7. IUCN Red List category as recorded by NatureServe: Endangered. NatureServe Explorer
  8. CITES listing recorded by NatureServe: Appendix II (controls on international trade). NatureServe Explorer
  9. NatureServe estimate of total adult population (global, as a range): 10,000 to >1,000,000 individuals. NatureServe Explorer
  10. NatureServe ranks Sea Otter as extirpated or possibly extirpated (SX or SH) in: Oregon. NatureServe Explorer
  11. NatureServe state ranks for Sea Otter (map and table on this page). NatureServe Explorer
  12. NatureServe notes on trend for Sea Otter. NatureServe Explorer
  13. Habitat types NatureServe records for Sea Otter: Bay/sound, Tidal flat/shore, Near shore. NatureServe Explorer
  14. NatureServe notes on habitat for Sea Otter. NatureServe Explorer
  15. Adult food habits recorded by NatureServe: Piscivore, Invertivore. NatureServe Explorer
  16. Estimated diet composition in EltonTraits 1.0: 50% invertebrates, 50% fish. EltonTraits 1.0
  17. NatureServe notes on food for Sea Otter. NatureServe Explorer
  18. Typical length recorded by NatureServe: 150 cm (59 in). NatureServe Explorer
  19. Typical adult weight recorded by NatureServe: 35 kg (77 lb). NatureServe Explorer
  20. Typical litter or clutch size in AnAge: 1. AnAge
  21. Gestation or incubation period in AnAge: 140 days. AnAge
  22. Age at female sexual maturity in AnAge: 974 days (about 2.7 years). AnAge
  23. Activity time in EltonTraits 1.0: crepuscular, diurnal. EltonTraits 1.0
  24. NatureServe migration category for Sea Otter: non-migrant, local migrant (populations can differ). NatureServe Explorer
  25. NatureServe notes on phenology for Sea Otter. NatureServe Explorer
  26. Adult activity patterns recorded by NatureServe: Circadian. NatureServe Explorer
  27. NatureServe notes on migration for Sea Otter. NatureServe Explorer
  28. NatureServe notes on reproduction for Sea Otter. NatureServe Explorer
  29. GBIF observation records of Sea Otter in the US by month (chart on this page). GBIF
  30. NPSpecies park lists recording Sea Otter as present (list on this page). NPS NPSpecies
  31. US states with the most GBIF observation records of Sea Otter: California, Alaska, Washington, Oregon, Hawaii. Record counts follow observer effort, not population size. GBIF

Status, range and habitat come from NatureServe Explorer (CC BY 4.0) and USFWS ECOS at the snapshot date. Listings change by federal rule. State lists are where NatureServe records the species, not a promise that you will see it there. Never name a place smaller than a state. GBIF and park records count observations and checklists. They show where and when people report the species, not how many animals live there.

NatureServe. 2026. NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org. (Accessed: October 30, 2026). Licensed under CC BY 4.0; SpeciesFacts selected and summarized it.

Photo: Mike Baird from Morro Bay, USA, CC BY 2.0, via Wikimedia Commons.