Animal Diversity Web

Ge­o­graphic Range

Za­lo­phus cal­i­for­ni­anus are found along the shore from Cal­i­for­nia to Mex­ico in­clud­ing Baja and Tres Marias Is­lands, in the Gala­pa­gos Is­lands and in the south­ern Sea of Japan (Schef­fer, 1958). The pop­u­la­tions in each area do not in­ter­act with other pop­u­la­tions (Schef­fer, 1958) and there­fore are con­sid­ered sub­species. Cal­i­for­nia sea lions tend to sea­son­ally mi­grate long dis­tances (Ried­man, 1990). Males usu­ally mi­grate north to British Co­lum­bia after the breed­ing sea­son (Mate, 1978).

• Biogeographic Regions
• nearctic
  • native
• pacific ocean
  • native

Habi­tat

Za­lo­phus cal­i­for­ni­anus gen­er­ally live along coast­lines but have been found in rivers in along the north­ern Pa­cific coast. Cal­i­for­nia sea lions often con­gre­gate on man-made struc­tures such as jet­ties, piers, off­shore buoys and oil plat­forms. Za­lo­phus cal­i­for­ni­anus tend to in­habit places which have un­der­gone human in­ter­ven­tion (Ried­man, 1990).

• Habitat Regions
• temperate
• saltwater or marine

• Aquatic Biomes
• rivers and streams
• coastal

Phys­i­cal De­scrip­tion

New­born pups av­er­age 75 cm in length and weigh be­tween 5 to 6 kg. Adult males av­er­age 2.2 me­ters in length and 275 kg in weight but can reach length of 2.4 me­ters and weights of 390kg. Fe­males are smaller, av­er­ag­ing 1.8 me­ters in length and 91 kg in weight but can reach lengths of 2 me­ters and weights of 110kg . Pups have a black­ish brown coat, which is molted by the first month and re­placed with a light brown coat. The light brown coat is shed after 4 or 5 months and re­placed with the adult pelage. Adult males are mostly dark brown with lighter belly and side col­or­ing. Adult fe­males are dark brown but can also ap­pear tan. Za­lo­phus cal­i­for­ni­anus ex­hibit pro­nounced sex­ual di­mor­phism . Adult males have an en­larged sag­gi­tal crest and a lighter pelage. In ad­di­tion to the head fea­tures males are more ro­bust and larger than fe­males. All Cal­i­for­nia sea lions have black flip­pers which are coated with short black stub­ble. The typ­i­cal den­tal for­mula is 3/2, 1/1, and 5/5.

(Mate, 1979,)(Jef­fer­son et al., 1993), and (Ried­man, 1990)

• Other Physical Features
• endothermic
• bilateral symmetry

• Range mass

  390 (high) kg

  859.03 (high) lb

• Range length

  2.4 (high) m

  7.87 (high) ft

Re­pro­duc­tion

Dur­ing breed­ing sea­son males claim ter­ri­to­ries. A male con­sis­tently oc­cu­pies a ter­ri­tory until fac­tors change and cause him to be dis­placed. Typ­i­cal oc­cu­pa­tion time is ap­prox­i­mately two weeks; few Z. cal­i­for­ni­anus males re­main at their site for longer. While guard­ing their ter­ri­tory, males re­main pre­sent and do not leave even in pur­suit of food. As ex­ter­nal fac­tors change, males re­place other males on the ter­ri­tory. Re­place­ment oc­curs through­out the en­tire breed­ing sea­son. Males are known to at­tack if oth­ers in­vade their ter­ri­tory. Cal­i­for­nia sea lions tend to breed on is­lands or re­mote beaches. Za­lo­phus cal­i­for­ni­anus ex­hibit mod­er­ate to ex­treme polyg­yny and tend to live in colonies of a few males and many fe­males. Fe­male Z. cal­i­for­ni­anus ex­hibit mate choice, by "re­spond[ing] dif­fer­ently to the at­tempts of var­i­ous males"(Ried­man, 1990).

• Mating System
• polygynous

The peak breed­ing sea­son oc­curs in early July. The total ges­ta­tion pe­riod is about 11 months (Ried­man, 1990). Most births occur from mid-May to mid-June (Schef­fer, 1958) with the ma­jor­ity of pups born in mid-June. The time be­tween birth and es­trus is about 28 days. Cal­i­for­nia sea lions reach sex­ual ma­tu­rity be­tween four and five years (Ried­man, 1990).

• Key Reproductive Features
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • internal

• Breeding season

  mating in July, births in mid-May to mid-June

• Average number of offspring

  1

• Average number of offspring

  1.2

  AnAge

• Average gestation period

  11 months

• Average gestation period

  259 days

  AnAge

• Range weaning age

  6 to 12 months

• Average age at sexual or reproductive maturity (female)

  4-5 years

• Average age at sexual or reproductive maturity (female)
  Sex: female

  1095 days

  AnAge

• Average age at sexual or reproductive maturity (male)

  4-5 years

• Average age at sexual or reproductive maturity (male)
  Sex: male

  1826 days

  AnAge

The lac­ta­tion pe­riod in Z. cal­i­for­ni­anus ranges from six months to a year. There are many pos­si­ble rea­sons for the vari­a­tion in lac­ta­tion pe­ri­ods in­clud­ing avail­abil­ity of food re­sources, the mother's age and health, the sex of the pup and the birth of a new pup. Za­lo­phus cal­i­for­ni­anus pro­vide more lengthy ma­ter­nal care for fe­male off­spring then for male off­spring, yet dur­ing lac­ta­tion both males and fe­males have equal ac­cess and re­ceive equal re­sources.

• Parental Investment
• female parental care

Lifes­pan/Longevity

The old­est recorded wild Z. cal­i­for­ni­anus lived 17 years (Mate, 1979).

In cap­tiv­ity, the old­est recorded Z. cal­i­for­ni­anus lived to be 31 years old. The age of Z. cal­i­for­ni­anus can be de­ter­mined by count­ing the num­ber of rings on cross sec­tions of its teeth (Mate, 1978).

• Range lifespan
  Status: wild

  17 (high) years

• Range lifespan
  Status: captivity

  31 (high) years

• Average lifespan
  Status: wild

  17.0 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Status: captivity

  30.0 years

  Max Planck Institute for Demographic Research

Be­hav­ior

Za­lo­phus cal­i­for­ni­anus are ca­pa­ble of div­ing to depths of 274 me­ters (Ried­man, 1990) and can reach speeds of 15 to 20 miles per hour while swim­ming (Mate, 1978). Like cer­tain other ma­rine mam­mals, Z. cal­i­for­ni­anus use a sys­tem of echolo­ca­tion to find food, ori­ent them­selves, and nav­i­gate un­der­wa­ter. Z. cal­i­for­ni­anus some­times adopt and fos­ter a pup that has been aban­doned by its mother (Ried­man, 1990).

The nor­mal body tem­per­a­ture of Za­lo­phus cal­i­for­ni­anus is 37.5 de­grees Cel­sius. Be­cause Z. cal­i­for­ni­anus can­not sweat or pant (Odell, 1981), in order to ther­moreg­u­late they must alter their ex­te­rior en­vi­ron­ment. For ex­am­ple, if the air tem­per­a­ture in­creases they seek cooler areas, such as water (Ried­man, 1990).

Pups ex­hibit many dif­fer­ent play be­hav­iors in­clud­ing mock fight­ing (Mate, 1978).

• Key Behaviors
• motile
• migratory
• territorial
• social
• colonial
• dominance hierarchies

Com­mu­ni­ca­tion and Per­cep­tion

• Perception Channels
• tactile
• chemical

Food Habits

Male Cal­i­for­nia sea lions have been known to as­sem­ble at the mouths of fresh water rivers where there is a steady sup­ply of fish. Cal­i­for­nia sea lions tend to feed alone or in small groups un­less there is an large quan­tity of food. Under con­di­tions of in­creased food sup­ply, Z. cal­i­for­ni­anus hunt in larger groups. Za­lo­phus cal­i­for­ni­anus have been known to feed co­op­er­a­tively with cetaceans, seabirds and har­bor por­poises. Often one species lo­cates a school of fish and sig­nals the pres­ence of food to the other species. While rare, it has been recorded that Cal­i­for­nia sea lions drink sea­wa­ter while not breed­ing (Ried­man, 1990).

Foods eaten in­clude: cephalopods, an­chovies, her­ring, Pa­cific whit­ing, rock­fish, hake, salmon, squid and oc­to­puses (Ried­man, 1990).

• Primary Diet
• carnivore
  • piscivore
  • molluscivore

• Animal Foods
• fish
• mollusks

Pre­da­tion

See Ried­man, 1990.

• Known Predators

  • great white sharks (Carcharodon carcharias)
  • bull sharks (Carcharhinus leucas)
  • killer whales (Orcinus orca)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Za­lo­phus cal­i­for­ni­anus used to be hunted for their hides and for an­i­mal food. Cal­i­for­nia sea lions are also used by the U.S. Navy for re­trieval pro­grams, in­clud­ing search and res­cue and re­trieval of mil­i­tary hard­ware. They are also used to pa­trol areas in search of threats. Cal­i­for­nia sea lions are widely used in ed­u­ca­tional pro­grams through­out the world be­cause of their agility and train­abil­ity. They are charm­ing am­bas­sadors for their sea lion cousins. (Mate, 1978; Mate, 1979)

• Positive Impacts
• ecotourism
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Cal­i­for­nia sea lions are thought by some to se­ri­ously re­duce stocks of com­mer­cially-valu­able fish such as salmon. They also may in­ter­fere with nets used by fish­er­men.

• Negative Impacts
• crop pest

Con­ser­va­tion Sta­tus

Za­lo­phus cal­i­for­ni­anus are well pro­tected in most areas. Oc­ca­sion­ally, they are trapped with a per­mit for dis­play in zoos, aquar­i­ums, and cir­cuses (Mate, 1979). In Mex­ico, a few Cal­i­for­nia sea lions are trapped each year, while in the United States they are fully pro­tected under the Ma­rine Mam­mal Pro­tec­tion Act.

Oc­ca­sion­ally Cal­i­for­nia sea lions pose a prob­lem for fish­er­men by steal­ing fish from com­mer­cial fish­er­men net­ting. A sig­nif­i­cant num­ber of Cal­i­for­nia sea lions have been killed as a re­sult of get­ting tan­gled in dis­carded fish­ing gear. (Ried­man, 1990). From 1983 to 1984, Z. cal­i­for­ni­anus ex­pe­ri­enced a de­cline of 60 per­cent in pup pro­duc­tion from pre­vi­ous years. Also dur­ing this time food re­sources de­clined, which led to in­hib­ited growth and in­creased mor­tal­ity. Dur­ing this time moth­ers left their pups ear­lier in search of food, which trun­cated the lac­ta­tion pe­riod, thus re­duc­ing the amount of nu­tri­ents a pup re­ceived and mak­ing it more sus­cep­ti­ble to death.

Ac­cord­ing to IUCN, the fol­low­ing sub­species are rec­og­nized:

Za­lo­phus cal­i­for­ni­anus ssp. japon­i­cus (ex­tinct)

Za­lo­phus cal­i­for­ni­anus ssp. wolle­baeki (vul­ner­a­ble)

Za­lo­phus cal­i­for­ni­anus ssp. cal­i­for­ni­anus (no spe­cial sta­tus).

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

Other Com­ments

Be­cause Z. cal­i­for­ni­anus are highly train­able (Ried­man, 1990), they are often used as per­form­ing an­i­mals in zoos, cir­cuses and aquar­i­ums (Jef­fer­son et al., 1993).

In 1970, a dis­ease called lep­tospiro­sis spread through­out the Cal­i­for­nia sea lion pop­u­la­tion via urine. This dis­ease was the first doc­u­mented wide­spread dis­ease in ma­rine mam­mals. The ori­gin of the lep­tospiro­sis was be­lieved to be Mex­ico due to the warmer water there, which was con­ducive to bac­te­ria growth. (Mate, 1978)

Con­trib­u­tors

Re­becca Price (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Kate Teeter (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Jef­fer­son, T., S. Leather­wood, M. Web­ber. 1993. Ma­rine Mam­mals of the World. Rome, Italy: United Na­tions En­vi­ron­ment Pro­gramme and Food and Agri­cul­ture Or­ga­ni­za­tion of the United Na­tions.

Mate, B. 1979. Cal­i­for­nia Sea Lion. Pp. 5-8 in FAO Ad­vi­sory Com­mit­tee on Ma­rine Re­source Re­search Work­ing Party on Ma­rine Mam­mals, ed. Mam­mals in the Sea vol. 2 Pin­niped Species Sum­maries and Re­port on Sire­ni­ans. Rome, Italy: Food and Agri­cul­ture Or­ga­ni­za­tion of the United Na­tions.

Mate, B. 1978. Cal­i­for­nia Sea Lion. Pp. 172-177 in D Haley, ed. Ma­rine Mam­mals of East­ern North Pa­cific and Artic Wa­ters. Seat­tle, Wash­ing­ton: Pa­cific Search Press.

Odell, D. 1981. Cal­i­for­nia Sea Lion - *Za­lo­phus cal­i­for­ni­anus*. Pp. 67-97 in S Ridg­way, R Har­ri­son, eds. Hand­book of Ma­rine Mam­mals: vol. 1: The Wal­rus, Sea Lions, Fur Seals and Sea Otter. Lon­don: Aca­d­e­mic Press.

Ried­man, M. 1990. The Pen­nipeds: Seals, Sea Lions, and Wal­ruses. Berke­ley, Cal­i­for­nia: Uni­ver­sity of Cal­i­for­nia Press.

Schef­fer, V. 1958. Seals, Sea Lions and Wal­ruses: A Re­view of the Pin­ni­pedia. Stan­ford Cal­i­for­nia: Stan­ford Uni­ver­sity Press.