Marine Mammal Research

Marine mammals are a popular research subject and even more so in the face of increasing awareness of climate change and other environmental issues. This also includes man-made threats such as whaling and pollution.

Marine mammals dwell in the ocean or rely on the ocean for food. There are three groups which are listed below plus several species of otter and the polar bear.

These mammals can be traced back to early forms of land dwelling mammals although they have evolved into sea creatures over time. Their adaptation is marked by several features such as a large size, streamlined body shape and an efficient temperature control system.

These adaptations include large fat reserves (whales) stored as energy, shortened limbs, e.g. fins and better able to retain core body temperature.   

Hawaiian marine mammal projects

There are research projects in Hawaii into marine mammal behaviour, for example the 'whalesong' emitted by humpback whales whilst residing in their breeding grounds. Other research looks at the sensory perceptions of dolphins and small whales: another is focussed upon the effect human intervention has on the lives of marine mammals and ecosystems in general.

These types of research are undertaken both in the laboratory and in the field and aim to create a greater understanding of the importance of conservation and the environment. 

Types of marine mammals

There are three classes of marine mammals which are:

  • Cetaceans
  • Sirenians
  • Pinnipeds

Cetaceans This refers to the order of whales, dolphins and porpoises. These warm blooded mammals are ideally suited to aquatic life and have developed a range of features to enable them to do so. Several of these species are known for their intelligence.

Sirenians

These are more commonly known as 'sea cows' and refer to a class of mammal which is herbivorous and lives in swamps, rivers and coastal marine waters. This group includes manatees and dugongs.

Pinnipeds

These are fin footed mammals which are known for their sleek, streamlined appearance and barrel shaped body. This group comprises seals and walrus.

Cetaceans and sirenians have fully adapted to life at sea and are unable to survive for any period of time out of water. Most species within these three classes are protected according to international law.

Communication

Cetaceans communicate by means of biosonar in which they emit sounds such as clicks, moans, whistles or 'singing'. They also use biosonar or 'echolocation' to detect objects in the water such as prey by emitting sounds which reverberate off this object. This enables them to locate and identify an object.

Sirenians have poor vision and auditory senses which means that they have to use personal contact with another mammal as a means of communication.

Pinnipeds use a series of loud trilling or teeth chattering noises to communicate with others. They also rely on close tactile communication especially between mothers and pups.