MARINE MAMMALS

                 " THE FEAR OF THE LORD IS THE BEGINNING OF THE KNOWLEDGE"

                                                                   Proverbs 1:7

 MARINE MAMMALS:

                                     Mammals are warm blooded, have lungs not gills, breathe air, and suckle their young. Human beings are mammals. So are whales, dolphins, and porpoises. As a group, these are the cetaceans.

SPERM WHALE:

Some whales have teeth, and the largest toothed whale of all is the sperm whale. They spend their days diving deep in search of giant squid. A sperm whale’s teeth can grow up to 20 cm (8 inch) in length.      

                                           

                           

BALEEN WHALES:

                               

Baleen whales like the humpback have fringed brushes called baleen plates that grow in rows from their top jaw. They filter food with these baleen plates. Baleen plates are used to filter tiny shrimp like creatures from water

                                                       

DOLPHINS:

                                          

Dolphins live in groups called schools. A school can contain 1,000 dolphins. Dolphins need to eat at least 10 kg (22 lbs) of fish each day, swallowing them whole. When hungry, they will “herd” a shoal of fish together at the sea’s surface before picking the fish off. Like all cetaceans a dolphin’s blowhole is on top of its head.

 

ECHOLOCATION:

                                

The thick pad, or melon, on the top of a dolphin’s head helps to produce clicks.Dolphins talk to each other with clicks. The clicks also help a dolphin to find its prey. How? Because the noise bounces off objects in the water. It’s called echolocation.

 

PORPOISES:

                       Porpoises are smaller than dolphins. Ther are six species.

     

Spectacled porpoises:

                                 

                      Spectacled porpoises look as though they are wearing white spectacles.

 

Dall’s porpoise:

                             

                  Dall’s porpoise is the largest porpoise, growing up to 2.4 m (7 ft 9 in)

 

Finless porpoises:

                                 

        Finless porpoises are the only ones that lack a dorsal (top) fin.

 

Harbour porpoises:

                                   

                         Harbour porpoises can often be spotted in shallow water, near harbours.

 

Vaquitas:

                             

            Vaquitas are the smallest of the porpoises, at just 1.5 m (4 ft) in length.

 

Burmeister’s porpoises:

                                        
                     Burmeister’s porpoise has a dark colouring, and a low dorsal fin.

 

 

 Can cetaceans breathe under water in the same way as fish?

                                    No. Cetaceans have lungs, not gills, and must come to the surface to breathe.