Mammals

Wholly aquatic mammals are confined to two orders, the Cetacea and the Sirenia. The Cetacea comprises some 78 species, all except five marine, distributed throughout the world’s seas. They include the largest living animals – the rorquals in the family Balaenopteridae. All cetaceans are carnivorous; the baleen or whalebone whales are filter feeders, feeding on organisms several orders of magnitude smaller then they are.

Of four living members of the order Sirenia, only one – the dugon Dugong dugon – is exclusively marine, occurring widely in costal waters of the Indo-Pacific. One other, the Caribbean manatee Trichechus manatus, is found in both marine and inland waters while the other two (the Amasonian manatee Trichechus inunguis and West African manatee T. senegalensis) enter coastal waters marginally if at all. All Sirenians are herbivores; marine populations feed mainly on sea-grasses.

The remaining marine mammals are all included in the order Carnivora. Two New World otters in the family Mustelidae feed largely or exclusively in marine waters; other otter species may frequent coastal areas but are predominantly inland water animals. Members of the three pinniped families Odobenidae (the walrus), Otariidae (eared seals) and Phocidae (earless seals) are all very largely aquatic, emerging on land to breed and rest, particularly when moulting; all are marine with the exception of one or two species of Phocidae. All species are carnivorous.

In contrast to most terrestrial mammal families, pinnipeds are considerably more diverse and more abundant at higher rather than lower latitudes. Of the 32 extant or recently extant species, only five occur within the tropics. Part of the explanation for this undoubtedly lies in the greater availability of suitable habitat at higher latitudes: 70% of continental shelf waters and just over 69% of the world’s marine area are found outside the tropics. However, this in itself is unlikely to account for the entire difference. It is likely that the greater productivity of shelf waters at high latitudes and of upwelling areas at mid-latitudes plays a major part.

VOCABULARY:

Mammal – ссавець Otter – видра

Cetacea – кити Walrus – морж

Carnivorous – м’ясоїдний Seal – тюлень

Whale – кит Terrestrial – земний

Manatee – морська корова, ламантин Moult – линяти

Herbivorous – травоїдний Abundant – багатий на щось

I. ANSWER THE FOLLOWING QUESTIONS:

1. What are the two orders of aquatic mammals?

2. What are the largest living animals?

3. Are cetaceans carnivorous or herbivorous?

4. What do Sirenians feed on?

5. What aquatic mammals emerge on land to breed and rest?

6. Why are pinnipeds more abundant at higher latitudes?

7. Does the greater productivity of shelf waters play any part in the diversity of pinnipeds?

II. GIVE THE ENGLISH EQUIVALENTS OF THE FOLLOWING WORDS AND WORD COMBINATIONS:

Ряд (підклас), вид, морський, живитися, прибережні води, виринати на поверхню, розмножуватися, різноманітний, широта, наявність, середовище існування.

III. TRANSLATE INTO ENGLISH:

1. Розрізняють два підкласи морських ссавців.

2. Усі кити є м’ясоїдними.

3. Деякі види видр часто трапляються в прибережній зоні.

4. Моржі виринають на поверхню, коли линяють.

5. На вищих широтах є підходяще середовище існування для морських ссавців.

IV. FILL IN THE BLANKS WITH THE WORDS GIVEN BELOW:

1. … give birth to live babies and feed their young on milk.

2. Animals feeding on milk are called … .

3. Mammals feeding on sea-grasses are … .

4. Seals … on land to breed and rest.

5. Only five … occur in tropics.

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Herbivorous, emerge, mammals, species, carnivorous.

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Birds

Defining marine birds, or seabirds, is somewhat more problematic than defining marine species in other groups. All birds breed in terrestrial habitats, but a large number obtain all or much of their food from aquatic or littoral habitats. Some of these, including all frigatebirds, tropicbirds, gannets and boobies, penguins and petrels, albatrosses and shearwaters are indisputably marine, in that they obtain all their food from marine habitats, almost invariably breeding along coastlines and spending most or all of their when not breeding out at sea. Many others, however, have less clear-cut habits. Some, such as a number of cormorants and shags have both resident inland and marine populations. Others, such as a number of gulls and terns and some ducks and geese may breed inland but spend the rest of the year living in coastal areas or out at sea. Yet others, such as sandpipes and other waders, typically feed in littoral or intertidal habitats rather than in the sea itself; many of these species also occur inland.

Adopting a somewhat arbitrary division, and excluding all wading birds with the exception of the grey phalarope, something over 300 species of birds can be considered wholly or largely marine.

In common with pinnipeds, seabirds show a latitudinal distribution in which diversity is much higher at higher latitudes than it is in the tropics. Two-thirds of all seabirds are confined as breeding species to these latitudes, compared with only 7% that are exclusively tropical. This stands in sharp contrast to the pattern found in most major terrestrial groups and many marine groups such as sea turtles, mangroves and reef-building corals in which species diversity increases dramatically with decreasing latitude. Diversity is also markedly higher in the southern than in the northern hemisphere, with over half of all seabirds species breeding in southern temperate and polar latitudes. Dominance of this region is even more marked in the Procellariidae, the family with the greatest number of truly marine species, in which over 60% of species breed at these latitudes and half are confined to it.

VOCABULARY:

Breed – розмножуватися Cormorant – великий баклан

Littoral – прибережний Shag – баклан чубатий

Frigatebird – фрегат (птах) Tern – крячок

Gannet – баклан Wader – чапля

Petrel – буревісник Phalarope – плавунчик

Mangrove – мангрове дерево Wading bird – болотяний птах

I. ANSWER THE FOLLOWING QUESTIONS:

1. Is it easy to define marine birds?

2. What birds are indisputably marine?

3. What birds breed inland but spend the rest of the year out at sea?

4. How many birds are considered wholly marine?

5. Where is the diversity of seabirds higher?

6. Does terrestrial species diversity decrease with decreasing latitudes?

7. Is diversity higher in the southern or in the north hemisphere?

II. GIVE THE ENGLISH EQUIVALENTS OF THE FOLLOWING WORDS AND WORD COMBINATIONS:

Наземне середовище існування, здобувати їжу, узбережжя, звички, живитися, траплятися, розмаїття, широта, модель, зростати, знижуватися, обмежуватися.

III. TRANSLATE INTO ENGLISH:

1. Багато морських птахів живиться у прибережних зонах.

2. Велика кількість чайок і крячок проводить більше часу на узбережжі.

3. Чаплі здобувають їжу на прибережних територіях.

4. Розмаїття морських птахів набагато нижче в тропіках, ніж на вищих широтах.

5. Наземні види більш різноманітні на нижчих широтах.

IV. FILL IN THE BLANKS WITH WORDS GIVEN BELOW:

1. All seabirds … in terrestrial habitats.

2. Penguins and petrels obtain their food from … habitats.

3. Some seabirds have both … and marine populations.

4. Two-thirds of all seabirds are confined to higher … .

5. Major … groups are more diverse at lower latitudes.

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Inland, terrestrial, breed, latitudes, marine

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