Monachus tropicalisWest Indian monk seal

Ge­o­graphic Range

Monachus trop­i­calis has of­fi­cially been de­clared ex­tinct. His­tor­i­cally, the range of Caribbean monk seals was in the trop­i­cal wa­ters of the Florida Keys, the Ba­hamas, the Greater and Lesser An­til­lies, around the Yu­catan Pen­nin­sula, and around off­shore islets and atolls. Cur­rently, un­con­firmed sight­ings are most com­mon in North­ern Haiti and North-east Ja­maica. It is the only pin­niped ever known to exist in the Caribbean re­gion. The last recorded sight­ing of M. trop­i­calis in the United States was in 1932 off the coast of Texas and a small group was sighted on Seranilla Bank, be­tween Hon­duras and Ja­maica, in 1952. (Boyd and Stan­field, Oct. 1998; De­brot, Oct. 2000; IUCN, 2008; Knud­sen, Oct. 1977)

Habi­tat

Lit­tle is known about the habi­tat of M. trop­i­calis. Likely, beach habi­tat was im­por­tant, how­ever they spent much of their time in the water. Caribbean monk seals oc­cu­pied a ma­rine en­vi­ron­ment, with rocky or sandy coast­line for shel­ter and breed­ing areas. Un­con­firmed sight­ings of M. trop­i­calis by divers usu­ally take place un­der­wa­ter. This sug­gests they are rarely seen at the sur­face, or when they are, they are rarely rec­og­nized. Re­cent ev­i­dence in­di­cates the ul­ti­mate con­tribut­ing fac­tor to the de­cline of Caribbean monk seals was loss of habi­tat. (Boyd and Stan­field, Oct. 1998; Lav­i­gne, Dec. 1998)

Phys­i­cal De­scrip­tion

Caribbean monk seals were known to be beau­ti­ful an­i­mals. They had brown pelage, lightly frosted with gray, fad­ing to a pale yel­low on the stom­ach. They had hood­like rolls of fat that sur­round their necks. Their hair was very short and stiff. The nails on the an­te­rior dig­its were well de­vel­oped, and nails on the pos­te­rior dig­its were sim­ple. Their soles and palms were naked. They have also had 4, rather than 2 mam­mary glands. Their den­tal for­mula was 2/1, 1/1, 5/5. It is likely that there was sex­ual di­mor­phism, with males reach­ing up to 200 kg in some ac­counts. Fe­males were likely smaller, rang­ing from 70-140 kg, al­though there is dis­par­ity in records. In­fants were born with coal-black pelage. (Knud­sen, Oct. 1977; Mac­don­ald, 1984)

  • Sexual Dimorphism
  • male larger
  • Range mass
    70 to 200 kg
    154.19 to 440.53 lb
  • Range length
    220 to 240 cm
    86.61 to 94.49 in
  • Average length
    222.50 cm
    87.60 in

Re­pro­duc­tion

The mat­ing sys­tem of these seals is un­known.

Very lit­tle is known about the re­pro­duc­tive be­hav­ior of M. trop­i­calis. Births were likely in early De­cem­ber be­cause sev­eral fe­males killed in the Tri­an­gle Keys dur­ing this time had well-de­vel­oped fe­tuses. One young per fe­male is thought to have been born. (Kenyon, Nov. 1972; Knud­sen, Oct. 1977)

  • Breeding season
    Births were likely to occur in early December.
  • Average number of offspring
    1

Lit­tle is known of the parental care of Caribbean monk seals. The nurs­ing pe­riod is likely to have been rel­a­tively short, be­cause the mother did not feed be­tween birth and wean­ing. It is un­known what role, if any, male parental care played. (Mac­don­ald, 1984)

  • Parental Investment
  • precocial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female

Lifes­pan/Longevity

Ac­tual lifes­pan of M. trop­i­calis is un­known. How­ever it is be­lieved the av­er­age life span was around 20 years. (Mac­don­ald, 1984)

  • Average lifespan
    Status: wild
    20 years

Be­hav­ior

Monachus trop­i­calis is thought to have been most ac­tive at dawn and dusk. This seal species was un­ag­gres­sive and cu­ri­ous, but also very sen­si­tive to dis­tur­bance. This likely con­tributed to the demise of M. trop­i­calis be­fore thor­ough in­ves­ti­ga­tions could be made into its be­hav­ior pat­terns. (Boyd and Stan­field, Oct. 1998; Seal Con­ser­va­tion So­ci­ety, 2001., date un­known)

Com­mu­ni­ca­tion and Per­cep­tion

Food Habits

Be­cause Caribbean monk seals were clas­si­fied as ex­tinct be­fore it was pos­si­ble to study them, their pri­mary diet is not known to sci­ence. It is as­sumed how­ever, that it fol­lowed the typ­i­cal monk seal diet of fishes and in­ver­te­brates. Caribbean monk seals are also as­sumed to have preyed on pelagic species, along with spiny lob­sters, eels, oc­to­pus, and var­i­ous other reef fish. (Boyd and Stan­field, Oct. 1998; Mac­don­ald, 1984)

  • Animal Foods
  • fish
  • mollusks
  • aquatic crustaceans

Pre­da­tion

Caribbean monk seals had rel­a­tively few preda­tors. It is likely that the biggest threats to them (other than hu­mans) were the sharks. Al­though they were agile swim­mers, these seals were not able to move quickly while on land. Bbe­cause of their iso­lated evo­lu­tion­ary his­tory, M. trop­i­calis was not equipped with an in­nate fear of pre­da­tion on land. This made them rel­a­tively easy tar­gets for pi­o­neers and fish­er­men. (Kenyon, Nov. 1972)

Ecosys­tem Roles

The exact role this species played in the Caribbean ecosys­tem is un­known. As preda­tors, they prob­a­bly had some af­fect on reg­u­lat­ing local fish pop­u­la­tions.

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Christo­pher Colum­bus was the first to note this species in his ac­counts. With the ar­rival of other Eu­ro­peans, M. trop­i­calis was re­lent­lessly ex­ploited for the com­mer­cially valu­able oil pro­duced from their blub­ber. It was also used, less com­monly, for meat. (De­brot, Oct. 2000; Seal Con­ser­va­tion So­ci­ety, 2001., date un­known)

  • Positive Impacts
  • food

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

It was be­lieved that M. trop­i­calis was a com­peti­tor to the fish­ing in­dus­try. This be­lief in­spired mass killings of M. trop­i­calis by fish­er­men. (De­brot, Oct. 2000)

Con­ser­va­tion Sta­tus

It is be­lieved that M. trop­i­calis is now ex­tinct. Al­though there are un­con­firmed sight­ings still in Caribbean areas, two ex­pe­di­tions in search of M. trop­i­calis failed to pro­duce any ev­i­dence that M.​tropicalis is still pre­sent in these wa­ters. (Boyd and Stan­field, Oct. 1998; De­brot, Oct. 2000; Knud­sen, Oct. 1977; Mignucci-Gi­an­noni and Odell, 2001)

Other Com­ments

Some re­searchers be­lieve that all seals evolved in trop­i­cal wa­ters where only 2 species sur­vive: Hawai­ian monk seals and Mediter­ranean monk seals, both of which are crit­i­cally en­dan­gered. Until the 1960's there was a third species in trop­i­cal wa­ters-- Caribbean monk seals. Today it is un­known whether this an­i­mal still ex­ists.

In 1493, dur­ing his fa­mous voy­age to the Amer­i­cas, Colum­bus dis­cov­ered the Caribbean monk seal. He called this crea­ture a "sea-wolf." Be­cause of its long iso­la­tion in the Caribbean and on the is­lands there, the species did not have the char­ac­ter­is­tic sus­pi­cious­ness dis­played by most seals. It was eas­ily killed for its blub­ber and meat. Once fish­er­men began to col­o­nize what lit­tle habi­tat M. trop­i­calis had left, the re­main­ing pop­u­la­tion suf­fered a loss.

Re­cently, two sci­en­tific crews set out to find M. trop­i­calis around Ja­maica and Haiti. Air sur­veys and per­sonal in­ter­views took place with fish­er­men in the area. About 23% stated they had seen a monk seal this, or last year. Be­cause there are only 3 trop­i­cal species of seal, sep­a­rated by oceans, it is be­lieved that these sight­ings in­di­cate the pres­ence of Caribbean monk seals. How­ever, be­cause of ex­panded com­mer­cial and sus­te­nance fish­ing, it is un­likely that these seals have been able to sur­vive. Undis­turbed habi­tat is nec­es­sary to meet the re­quire­ments of this an­i­mal, and in this area such habi­tat is very lim­ited. Un­con­firmed sight­ings of monk seals in their na­tive range are prob­a­bly of wan­der­ing hooded seals (Cystophora cristata), which have been con­firmed near Puerto Rico and the Vir­gin Is­lands. (Boyd and Stan­field, Oct. 1998; IUCN, 2008; Kenyon, Feb. 1977; Kenyon, Nov. 1972; Knud­sen, Oct. 1977; Lav­i­gne, Dec. 1998; Seal Con­ser­va­tion So­ci­ety, 2001., date un­known)

Con­trib­u­tors

Laura Davies (au­thor), Hum­boldt State Uni­ver­sity, Brian Ar­bo­gast (ed­i­tor), Hum­boldt State Uni­ver­sity.

Glossary

Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

World Map

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

crepuscular

active at dawn and dusk

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

food

A substance that provides both nutrients and energy to a living thing.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

molluscivore

eats mollusks, members of Phylum Mollusca

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

piscivore

an animal that mainly eats fish

reef

structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

young precocial

young are relatively well-developed when born

Ref­er­ences

Boyd, I., M. Stan­field. Oct. 1998. Cir­cum­stan­tial ev­i­dence for the pres­ence of monk seals in the West In­dies. Oryx, 32: 310-316.

Copy­righted 1997 Texas Tech Uni­ver­sity, "The Mam­mals of Texas - On­line Edi­tion" (On-line). Ac­cessed Oct. 19, 2001 at http://​www.​nsrl.​ttu.​edu/​tmot1/​monatrop.​htm.

De­brot, A. Oct. 2000. A Re­view of Records of the Ex­tinct W. In­dian Monk Seal. Ma­rine Mam­mal Sci­ence, 16 (4): 834-837.

IUCN, 2008. "Monachus trop­i­calis" (On-line). 2008 IUCN Red List of Threat­ened Species. Ac­cessed Oc­to­ber 07, 2008 at http://​redlist.​org/​details/​13655.

Kenyon, K. Nov. 1972. Jour­nal of Mam­mal­ogy, 53: 687-696.

Kenyon, K. Feb. 1977. Caribbean monk seal ex­tinct. Jour­nal of Mam­mal­ogy, 58 (1): 97-98.

Knud­sen, P. Oct. 1977. The Case of the Miss­ing Monk Seal. Nat­ural His­tory, 86 (1): 78-83.

Lav­i­gne, D. Dec. 1998. "The Monachus Guardian: His­tor­i­cal bio­geog­ra­phy and phy­lo­ge­netic re­la­tion­ships among mod­ern monk seals, Monachus spp." (On-line). Ac­cessed Oct. 17, 2001 at www.​monachus.​org/​library.​htm#​BACK%20ISSUES.

Mac­don­ald, D. 1984. The En­cy­clo­pe­dia of Mam­mals. Barns & Noble Books, Spain: An­drom­eda Ox­ford Lim­ited.

Mignucci-Gi­an­noni, A., D. Odell. 2001. Trop­i­cal and sub­trop­i­cal records of hoodd seals dis­pel the myth of ex­tant Caribbean monk seal.. Bul­letin of Ma­rine Sci­ence, 68(1): 47-58.

Seal Con­ser­va­tion So­ci­ety, 2001., date un­known. "Seal Con­ser­va­tion So­ci­ety: Caribbean Monk Seal" (On-line). Ac­cessed Oc­to­ber 15, 2001 at http://​www.​pinnipeds.​org/​species/​caribmnk.​htm.