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.
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.
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.
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.