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.
- Biogeographic Regions
- nearctic
- neotropical
- atlantic ocean
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.
- Habitat Regions
- temperate
- tropical
- saltwater or marine
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.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
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.
- Key Reproductive Features
- iteroparous
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
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.
- Parental Investment
- precocial
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
provisioning
Lifespan/Longevity
Actual lifespan of
M. tropicalis
is unknown. However it is believed the average life span was around 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.
- Key Behaviors
- natatorial
- crepuscular
- motile
- solitary
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.
- Primary Diet
-
carnivore
- piscivore
- eats non-insect arthropods
- molluscivore
- 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.
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.
- 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.
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.
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.
Additional Links
Contributors
Laura Davies (author), Humboldt State University, Brian Arbogast (editor), Humboldt State University.
- 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.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- 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.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- 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.
- saltwater or marine
-
mainly lives in oceans, seas, or other bodies of salt water.
- 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.
- coastal
-
the nearshore aquatic habitats near a coast, or shoreline.
- 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.
- 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.
- 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).
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- 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
- natatorial
-
specialized for swimming
- crepuscular
-
active at dawn and dusk
- motile
-
having the capacity to move from one place to another.
- solitary
-
lives alone
- food
-
A substance that provides both nutrients and energy to a living thing.
- carnivore
-
an animal that mainly eats meat
- piscivore
-
an animal that mainly eats fish
- molluscivore
-
eats mollusks, members of Phylum Mollusca
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
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 .