Marine Biology - Whales - Case Study Example

Marine Biology: Whales Whales are largest living mammals belonging to the broader order of cetacean, which also comprises porpoises and dolphins. Whales are further classified into two suborders that are toothed and Baleen whales. The main distinguishing factors are the feeding habits and physical characteristics. Baleen whales have two blowholes and a unique comb-like feature called baleen special for filtering seaweeds, planktons, crustaceans, as well as small fish. Among all whale species, Baleens are the largest and populous. On the order hand, toothed whales with one blowhole and have teeth making them more carnivorous feeding on squid, fish, marine mammals and eve whales of other species. Just like any other mammal, whales inhale air into their lungs through blowholes at the top and they breastfeed their young ones called calves. Furthermore, they are warm-blooded and have scanty hair. They have streamlined bodies just like fish that make them easily cruise through deep waters with minimal resistance and friction. Their forelimbs assume the peddle shape for propulsion through water. Enormous propulsion power is derived from a combined effort the fore limbs and the tail flukes. They communicate through variety of sounds. Furthermore, they are considered the noisiest animals living today. Whales are classified in several species basing on their physical and feeding characteristics. They include; blue whale, gray whale, bowhead whale, minke whale, narwhal whale, pilot whale, sperm whale and beluga whale. Whale Species Description Bowhead whale has an average length of 14-15 meters with females being larger than males, weighing 50-60 tones. They are skim feeders preying on copepods and krill. This species migrates Northwards during spring and Southwards during autumn. They are largely found in the circumpolar high altitudes of the Northern Hemisphere. North Atlantic right whale; this is a skim feeder preying on copepods measuring 13.5-17 meters long and weight ranging 40-80 tones. They are found in Western North Atlantic and Fundy Bay during summer, in spring they are found in Cape Cod having their main breeding grounds in Florida during winter. They oscillate between lower-latitude breeding zones in winter to high-latitude feeding grounds during summer. Gray whale; they have average length of 13-14 meters, weighing 14-35 tones and are bottom feeders preying on benthic amphipods. They are found in the North Pacific Ocean and migrate between lower-latitude breeding zones in winter to high-latitude feeding hubs in summer. Females are lager in size than males. Blue whale; this whale measures 25-26 meters long weighing 100-120 tones making it the largest of all whales. Blue whale feeds through lunging and gulping preying on krill, they move to Polar Regions to feed during summer and return to lower latitudes during winter for breeding. They are distributed all over the blue waters ranging from the equator region to both hemispheres of Polar Regions. Fin whale species feed through lunging and gulping with primary prey as krill and schooling fish. Measures 21-22 meters long with females being larger than males. They weighs 45-75 tones and with a worldwide distribution. They are found in temperate regions to polar waters and less frequent in tropics. They migrate between high-latitude feeding regions during summer and lower-latitude grounds for breeding in winter. It is estimated that a single fin whale can urinate up to 970 liters in a day. Sperm whale; males are 15 meters long while females are 11meters long, they do their feeding near the ocean bottom with squid and fish as their main prey. They are distributed all over the blue waters from the equatorial region to Polar Regions. Male adults migrate latitudes past 45 degrees in all the hemispheres in such for food. There is notable migration from higher to lower latitudes between summer and winter in some assorted populations. Sperm whales have the largest and heaviest brain in the animal kingdom weighing up to 9 kilograms. Humpback whale;12-14 meters in length, weighs between 25-30 tones and feed through lunging and gulping with small school fish and krill as the primary prey. This species is widely distributed seasonally surfacing in all oceans from Antarctic to Arctic regions. Migrate between high and mid latitude summer to feed and to the tropical regions during winter breeding and calving zones. Reproduction Whales give birth to young ones called calves, mothers lactate this young whales until maturity just like other mammals. Breeding is seasonal in warm tropical regions with one female bearing a calf every 1-3 years. They have longer gestation periods ranging from 9-18 months depending on the species. The strong bond between mothers and calves is due to the long association period that goes for more than a year. This also provides protection of younger whales to survive the harsh predatory aquatic life. Whale Behavior Most whales specifically baleen whales move long distances from their usual Coldwater feeding zones to warmer regions for breeding annually. They travel singularly or in-group formations during their yearly migration. Toothed whales are known to hunt in groups, migrate as a team, and share duties in upbringing of their young ones. Whales are active and highly mobile while in water, they flex and manipulate their bodies jumping high out of water then back with their tails slapping and flipping out of water frequently. Whales have a distinguished way of communication through lyrical sounds. The sounds are acutely loud varying from species to species and can be heard a couple of miles away. Whales are known conscious breathers by the fact that they decide when to breathe by intentionally coming out of water to get enough air. Whales also sleep but not too long since they need to breathe occasionally by accessing the water surface. Cuvier’s beaked whales can dive up to three thousand meters for a period more than 2 hours followed by sperm whales that can dive up to 2000 meters in two hours. Whales can live for more than one century especially the Bowhead whales. They spend most of their lives in the Cold Artic waters making them less susceptible to fishing and other known aquatic threats that shorten lifespan. Humpbacks, which feed in the Antarctic region and move to the north for breeding, cover the longest migration of mammals. Close to the Humpbacks are the Gray whales that move enormous distance, they circumnavigate an average of 11000 miles annually between their breeding lagoons in warmer waters and feeding zones in the arctic region during summer. Threats to whales The number of whales today is worrying as compared to some years ago; this is because they are several menacing factors towards the existence of whales. To begin with, the changing climate is not giving a good chance for the whales to thrive. Almost all marine life whales included are experiencing changes in their breeding seasons. Too long summer and winter are the factors disrupting the normal sea life. The changes in the sea temperatures and level make whales more susceptible and may not adapt fast enough to survive. Similarly, the major habitats of whales; the Arctic and Antarctic regions experience the same threats from climate change. The source of food foe whales is drastically diminished due to either excessive fishing, water population or climatic changes. For instance, the krill, which are the primary source food for whales, have decreased over time. This means that if the whale species are not going to adapt swiftly to a new feeding style then they are likely to be depopulated by starvation. Conclusion Apart from whales being the largest living mammals of both terrestrial and aquatic life, they exhibit a very interesting life pattern. The many whale species have their unique physical features and distinguished characteristics. All species differ in body size, feeding habits, weight and migration pattern as well as distribution. However, they all tend to breed in the same time of the year in specific places of the blue waters. Once the calves are born, mothers take care of them until they reach maturity. Today these great mammals have several threats that are likely to limit their survival. Climate change together with human activities interferes with the feeding pattern and breeding of whales (Whale Life Documentary, retrieved from https://www.youtube.com/watch?v=wYImXDBwoew) Works cited Whale Life Documentary, Retrieved from https://www.youtube.com/watch?v=wYImXDBwoew Read More