Species: Three species:
Mediterranean Monk Seal
Caribbean Monk Seal
Hawaiian Monk Seal
Hawaiian monk seal, Monachus
Monk seals belong to
the Mammalian Order Pinnipedia, in the family Phocidae. Other
members of Phocidae include elephant seals, gray seals, and leopard
seals. Phocids are referred to as true seals. They are
distinguished from other pinnipeds by their inability to support
their body using their hind limbs.
The monk seal's
scientific name generic name, Monachus, means "monk". This
probably describes the seals' occasional solidarity, as well as
their large rings of neck fat which resemble a monk's hood. The
Hawaiin monk seal's specific name, schauinslandi, refers to a
German zoologist, Professor H. H. Schauinsland (1857-1937),
responsible for discovering the seal. The Mediterranean monk
seal's specific name monachus, which means "monk". The
Caribbean monk seal's specific name, tropicalis, means
"belong to tropical regions", which refers to the tropical
environment of the Caribbean.
Monk seals exhibit
morphological characteristics developmentally more primitive than
prehistoric seal fossils dating 14.5 million years. This group of
seals is the most ancient-looking of all seal species. The Hawaiian
monk seal separated from an Atlantic-Caribbean monk seal population
15 million years ago. They share similar coloration with the
Caribbean monk seals. Both are brownish gray dorsally, with yellow
underbellies and muzzle. The Mediterranean monk seal is also
brownish gray, but has a distinctive white patch on its underside.
Monk seals range in size from 6-7.5 feet. Mediterranean monk seals
are the largest species, usually weighing about 700lbs. Males and
females are similar in weight and length. Hawaiian monk seal
females weigh less about 550lbs, and males weigh about 370lbs.
Males are significantly smaller than females. Caribbean monk seals
are the smallest, weighing about 350lbs.
Monk seals are the
only tropical phocid species. All other seal species live in the
temperate and polar regions close to the Arctic or Antarctic. The
Hawaiian monk seal is endemic to the southwestern beaches of the
northwestern islands and atolls of the Hawaiian archipelago. In
fact, along with the hoary bat, Hawaiian monk seals were one of two
mammal species present on the Hawaiian archipelago before humans.
seals inhabit a variety of nations bordering the Mediterranean and
Aegean Seas. Populations are found in Greece, Turkey, Albania,
Morocco, and Algeria. The mid-Atlantic populations live on the
archipelagos and coast of Mauritania. Secluded beaches and caves
away from human disruption are the preferred locations for monk
seals. The beaches of the Mediterranean have become so crowded that
Mediterranean monk seals haul out in ocean caves, some only
accessible from underwater.
Caribbean monk seals
once inhabited islands throughout the Caribbean Sea and the Gulf of
Mexico. Formally declared extinct in the 1996 IUCN Red List of
Threatened Animals, the location of any surviving monk seals is
unknown. The last confirmed sighting of the species occurred
between Jamaica and Honduras, on the Island of Seranilla Bank in
1952. More recent sightings within their former range have been
Mediterranean monk seals feed primarily on lobster, octopus, and a
variety of fish. Fish prey species include eel, tuna, sardines,
flatfish, and mullet. The Caribbean monk seal was poorly studied
before it became extinct. Consequently, its diet is mainly unknown.
Hawaiian and Caribbean
monk seals evolved on islands without land predators. Sharks are
their main predator, especially the Galapagos shark. A lack of land
threats resulted in relatively docile behavior towards terrestrial
animals. Both species became easy targets for hungry sailors.
Despite the fear of land intruders by Hawaiian and Caribbean monk
seals, all three species are easily disturbed by human presence.
Seals will abandon pupping beaches. Disruption of nursing often
results in the death of the pup. Due to their conflicting ranges
with human tourism, this disruption has become a serious
Hawaiian monk seal, Monachus
Monk seals lead
solitary lives. They are not migratory species. Pupping beaches
and feeding grounds are within the same range. Seals return to
beaches each year to pup. Males travel the beaches within their
range for receptive females. A breeding practice by male Hawaiian
monk seals, called mobbing, has become a conservation threat.
Females and juveniles of both sexes are attacked by groups of males
intending to breed. In the Hawaiian monk seal population, males
outnumber females three to one in some colonies. Mobbing has become
a threat to monk seal survival in those colonies. Breeding for
Hawaiian monk seals occurs in May and June. Breeding for
Mediterranean monk seals occurs in October and November. Delayed
implantation occurs, and the time between fertilization and birth is
about one year. Monk seals of all species are 20-30lbs in weight
and about three feet in length at birth. A dark brown or black coat
is characteristic of all species. Mediterranean monk seal pups have
a characteristic yellow patch on their underside. The female seal
does not feed during the nursing period. She relies on stored fat.
Seals are weaned at about six weeks. They weigh between 150-200lbs
at weaning age. The black lanugo coat is molted at this time.
Mediterranean monk seals of both sexes reach sexual maturity at 4-6
years. Hawaiian monk seals of both sexes mature sexually at 5-9
years. The lifespan of a monk seal is 20-30 years.
The Caribbean monk
seal was formally declared extinct in the 1996 IUCN Red List of
Threatened Animals. The Mediterranean monk seal is the most
endangered pinniped, with fewer than 400 individuals remaining.
The Hawaiian monk seal is the second most endangered pinniped, with
about 1,300 individuals remaining. The tropical environmental
preferences of these species place them in direct competition with
humans, who also enjoy tropical climates. Monk seals are easily
disturbed by the presence of humans as well. This behavioral
characteristic prevents the coexistence of monk seals and tourists
on European and Hawaiian beaches. Nets from commercial fishing
boats incidentally drown monk seals. The bioaccumulation of toxins
in monk seals from ocean pollutant is another cause of death. Also,
Hawaiian and Mediterranean monk seals are both protected under the
United States' Marine Mammal Protection Act of 1972 and the
Endangered Species Act of 1973.
Hawaiian monk seal
populations suffer from a variety of threats. Ciguatera, a toxin
that naturally occurs in dinoflagellates of the marine food chain,
builds up in Hawaiian monk seal prey species. Significant die-offs
have occurred from this poison. This species recovered minimally
during the early 20th century. During this time the northwestern
Hawaiian Islands were designated as a bird reserve. The advent of
World War II altered the fortune of the monk seal. Naval bases were
established, and naval engagements took place throughout the
Hawaiian archipelago. This disruption caused the species to decline
between 1950 and 1980. Nature preserves and sanctuaries have since
been established to guard Hawaiian monk seals from human disruption.