Mammal Marine Biologists 101

There are several aspects of marine biology. Some of these tend to be very boring and take several trials and repetitions before you can come up with a definite conclusion or results. If you, however, study mammals instead, you may realize that research tends to become more interesting and easier, since these animals react very quickly. You will have more data to gather and observe, thereby providing you the opportunity to enhance your skills.

The 3 Orders

Marine mammals are generally grouped into 3 orders. The order Cetacea includes dolphins, whales and porpoises. The order Pinnipedia involves walruses, seals and sea lions. The order Sirenia includes dugongs and manatees.

The whole lifecycle of the order Cetacea is aquatic. There are a couple of sub-orders founded on the feeding mechanism, namely Odonticeti and Mysticeti. The order Pinnipedia involves part of their lifecycle being terrestrial. The word Pinnipedia means “feather-footed” since the animals possess 4 webbed fins. These can be found in all oceans, but most reside at high latitudes, traveling usually in herds and carrying out very long migrations. The order Sirenia usually spends their whole lifecycle in the water. These are the only aquatic animals that eat plants mainly.

The Suborders of Cetacea

The sub-order Mysticeti includes baleen whales and blue whales. These animals use baleens or brush-like triangular continuously renewing plates that hang from the roof of the mouth, with 480 plates on each jaw side. The plates filter zooplankton, squid and small fish, with the tongue moving the food into the throat.

Right whales are skim feeders, grey whales feed via a suction mechanism on animals living on the bottom of the ocean and minke whales feed by gulping and lunging. Different whales use various approaches to eat successfully. The sub-order odonticeti includes mammals that have their first teeth remain until they die. These grasp and swallow whole prey. A good example is the killer whale.

About the Pinnipeds

Pinnipeds have a low SA/V ratio and develop insulation via their hair and blubber. Fur seals can have so many hair belonging to either underfur fibers and guard hairs. These all moult, especially during the summer after breeding period, while others just remain out of the water until complete. Pinnipeds exhale before deep dives and have high myoglobin and hemoglobin concentrations. These animals feed usually on fish and squid. The walrus will use their tusks to dig for animals living on the bottom.

The Sirenia

Sirenians are distributed widely but are usually caught for their hides, meat and oil. They are particularly prone because they are placid and slow moving. Danger comes mainly from powerboats at present and their loss of habitat. These animals are very social but now prefer to go in family groups or alone.

Dugongs are usually found in the Pacific and Indian Ocean. Manatees can be found in Atlantic coastal waters. Sireneans inhale before they dive into the water, just like whales. These can dive for 10 to 20 minutes. Bristles can detect food to help themselves tide over the lean months.

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The Marine Mammals

Studying marine mammals may be one of the most interesting parts in a marine biologist’s profession. There are 3 main orders that you need to know about. Each category has its own unique mechanism, feeding pattern and characteristics. These animals tend to live in different places as well, others in groups and the rest in families or alone. Once you become familiar with their lifestyle and features, you get to appreciate the species more.

Cetacea Order

The whole lifecycle of the order Cetacea is aquatic. There are a couple of sub-orders founded ont he feeding mechanism – Odonticeti and Mysticeti. The sub-order Mysticeti includes baleen whales, blue whales, minke whales, grey whales and right whales. The whales feature mechanisms to boost the success feeding.

The sub-order Odonticeti includes animals like killer whales, dolphins, toothed whales and porpoises. River and coastal species reside in small home ranges if they are offshore. Others prefer warm equatorial waters, while the rest are located in every ocean like the bottle-nosed dolphins and killer whales. Some animals like big baleen whales move from the tropics for winter breeding to high latitudes for summer feeding. Animals propel themselves using the broad and boneless tail flukes. They also shed skin and exude oil as much as 12 times per day to reduce friction.

Pinnipedia Order

These animals adapt to the environment through a variety of processes. Heat conservation is done and get a low SA/V ratio and develop insulation through their hair and blubber. All the animals moult, after breeding in the summer while the others should stay out of water until everything is done.

The respiration is done by exhaling before the deep dives. They have relatively high concentrations of haemoglobin and myoglobin. The heart of the animals drop during deep dives and the blood is limited to the heart and brain. Dives can be as deep as 1700m, lasting anywhere between 80 to 160 hours.

Sirenia Order

Sirenians are sought mainly for their hide, oil and meat. They spend their entire lives in the water and are the only aquatic animals labeled as herbivores. The flat tail propels itself via paddles. These can walk at the benthic or move backwards. Locomotion is usually slow but they can also burst at around 13 knots. Sirenians inhale before they dive, just like whales.
When they breathe, they can swap about 90% of lung volume.

Manatees can see very clearly underwater, while taste and smell are retained. These touch when they greet each other and lead to chirps, between calf and mother. Dugongs can live for as long as 70 years but fecundity is rather low. The animals reach puberty at 10 years old and produce only 1 calf every 5 years. Their population has to be protected to maintain the ability to recover from environmental stress and hunting.

Interacting with Man

All animals have interactions with man, although sirenians are the most widely known to be friendly towards humans. Fishing nets and fishing lines tend to be a problem for most of these animals.

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