Monachus

Hawaiian monk seal

Monk seals (Monachus ) are a genus of the earless seals. The only seals inhabit year-round tropical and subtropical seas. Today monk seals are distributed throughout different regions of the world, but rarely anywhere. Are known the following three types:

• Mediterranean monk seal, Monachus monachus ( Hermann 1779)
• Hawaiian monk seal, Monachus schauinslandi ( Matschie 1905)
• Caribbean monk seal, Monachus tropicalis (Gray 1850)

The reason for the wording can no longer be traced today. A tentative explanation is that the layer of fat in the neck area is a reminder of the habit of a monk.

Mediterranean Monk Seal

→ Main article: Mediterranean monk seal

The only seal of the Mediterranean has become extremely rare by persecution. The IUCN estimates the remaining population at 350 to 450 individuals, bringing the Mediterranean monk seal is one of the rarest mammals in Europe.

Hawaiian monk seal

→ Main article: Hawaiian Monk Seal

Once common on all coasts of the Hawaiian Islands, this species is now pushed back to the small, uninhabited Leeward Islands in the northwest of the archipelago. Found only on five of the islands Young rearing instead, but outside the breeding season the seals migrate far and wide and reach while the beaches of the main islands in the Hawaiian chain.

Hawaiian monk seals are 220 ​​cm long and 170 kg ( males ) and 270 kg ( females ) difficult. The color is light gray on the upper side and lower side slate gray. The animals live solitary and mate in the water. After the females have thrown her baby on the beach, they stay about 40 days for him to suckle it. During this time, they lose up to 90 kg body weight.

The constant adjustment by the people had the stocks reduced so much that keeping the Hawaiian monk seal extinct 1824. Undetected remained stocks to small and remote islands, including the Midway Islands. In the 1950s, it was estimated the stock to 150 animals. When the Midway Islands were largely bulldozed for the construction of an air force base, also the local population disappeared. Since then, the small Leeward Islands are the only remaining area of ​​distribution. By protective measures, inter alia, Appointment of the entire island chain to Papahānaumokuākea Marine National Monument in 2006, there was now back 1,200 Hawaiian monk seals, whose biggest threat now seem to represent not the people, but shark attacks.

Caribbean monk seal

→ Main article: Caribbean monk seal

The Caribbean monk seal is extinct with high probability. Even Columbus described after his first trip, the encounter with this seal, which was thus the first discovered by the Spaniards mammal in the New World. She was spread throughout the Caribbean and the Gulf of Mexico. The last time a colony of Caribbean monk seal was seen in 1952 on the Seranilla sandbar (south of Jamaica). Since there is no scientifically confirmed sighting anymore, although fishermen occasionally claim to have spotted these seals. However, scientific search expeditions to the rediscovery of this species of seal have brought no positive result. 2008, the type of the U.S. government was officially declared extinct.

System

Many zoologists have the monk seals described as particularly "primitive" seals. Bonner even goes so far as to call the genus and in particular the Hawaiian monk seal as "living fossils". Various anatomical details have led to the assumption that monk seals would be a particularly old group. Thus we find here, unlike other seals no enlargement of the temporal bone surrounding the inner ear; this increase is interpreted as an adaptation to the hearing under water, the lack of this feature thus indicates an unfinished adaptation. In addition, calf and shin are not knee - end fused together, a feature that monk seals have in common with land predators. Whether all of these features can be really close to a basal position of the monk seal, has recently become controversial again.

After Wyss 1988, the Mediterranean monk seal and the Caribbean monk seal are related to other earless seals closer than with the Hawaiian monk seal. Thus, it would be at Monachus a paraphyletic taxon. The lines parted apparently 15 million years ago, when Central America was closed and lost the marine connection between the Atlantic and Pacific.

Bininda - Emonds and Russell came in 1996 with their cladistic analyzes of the earless seals, however, a contrary view. In their opinion, the monk seals are very well monophyletic. The frequently expressed view of the monk seals as basal or even particularly "primitive" group within the earless seals also could not be confirmed in the study.