Cetaceans
There are many forms of cetacean life living in the worlds waters. How an why they came into existence is uncertain, but there have been many theories. Some say that dolphins are aquatic forms of goats, and others believe they evolved just like everything else, from a single cell, and not from an actual multi-cellular being. Because most cetaceans have some vestigial structures such as under-developed os coxae, the former of these two theories remains prevalent in most researchers minds.
The theory that cetaceans evolved from a goat-like being is not at all farcical. The similarities between the skeletal systems are more than coincidental. The only difference is that the cetaceans adapted to a marine lifestyle. The front limbs became modified as paddle-shaped flippers, the bones of which are still reminiscent of jointed limbs and digits, but the hind limbs were lost. The broad horizontal tail flukes that provide the main propulsive thrust bear no anatomical connection to the lost hind limbs, but are a seperate and distint development. They contain no bone, and owe their firm and yet flexible shape to underlying fibrous elastic tissue. The body is enveloped in a thick layer of blubber that aids in bouyancy, helps to preserve body heat, and is a source of stored energy. A cetacean’s skin is free of sweat glands, oil glands, or hair, and feels much like smooth, wet rubber to the touch.
Cetaceans, like other mammals, have lungs. They breathe air through a single nostril, or pair of nostrils, located on the top of the head; but contrary to a popular image, they do not “spout” water when they exhale. The visible spout, the size and shape of which is unique to many species, is simply water vapor in the lungs and a small amount of water present in the depression around the blowhole, which is blown into the air as th cetacean exhales.
A number of physiological adaptations enable whales to perform deep dives. First, they have a larger blood volume than land mammals of comparable size and weight, and they also have a greatly increased capacity to store oxygen in their blood and muscle tissue. Second, each breath provides an 80 to 90 percent renewal of air in the whale’s lung, compare with only 10 to 20 percent in most land mammals. Third, cetaceans have a resistance to the metabolic by-product carbon-dioxide, the buildup of which in the tissues, rather than the lack of oxygen, triggers the involuntary breathing response of most mammals.
Ceratopsians and Pachycephalosaurs are closely related in their characteristics. Ceratopsians processed a saddle-shaped boney frill that extended from the skull to the neck and typically had horns over the nose and eyes. The most popular was the triceratops, which could reach over 26 feet and weigh in excess of twelve metric tons. Their frills served as two major functions. It protected the vulnerable neck from being harmed. The second major function that the frill provided was due to the fact that the frill contained a network of blood vessels on its underside, which were used as a means to get rid of excess heat. The Pachycephalosaurs were considered to be bipedal. They were also found to have thick skulls, flattened bodies, and tail that were covered in an array of body rods. Pachycephalosaurs were thought to have been more than fifteen feet long and processed a skull that was surrounded by a rounded dome of solid bone. It was thought that they used their heads in combat or mating contests, but that was disproved fairly recently, which I will discuss later in the paper. Both Ceratopsians and Pachycephalosaurs were “bird-hipped” and both of these suborders contained a backwards pubic bone. Both were Marginocephilia, or “fringed heads”, which is one of three clads under the Orinthiscia order. They were also herbivore dinosaurs that inherited their fringe at the back of the skull from earlier ancestors.(2) Their classi...
Dolphins make up the largest and most diverse family of cetaceans. The family contains 26 recognized species of which 13 tend to have long well defined beaks and streamlined robust bodies. Many vary in size, shape, colors, beaks and flippers, as humans have various characteristics.
The background of this article gives information that is necessary to understand the experiment. The shape of the pelvic girdle is an appropriate predictor of both phylogeny and movement in terrestrial vertebrates. However, in marine vertebrates, the gravitational forces typically applied to terrestrial pelvic girdles are not there and therefore have little impact on the shape of the girdle. Pelvic girdles of fish are generally not attached to the vertebrae and primarily are used as a place for muscles to attach and supporting of the fins. The authors discuss how in many cases the pelvic girdle could be removed and not result in any complications. However, there are some marine vertebrates that are capable of bottom walking on the ocean floor with their fins. In batoids, the pelvic fins are used for walking, which is when pelvic fins move in an alternating fashion, or punting, when both pelvic fins move at the same time. There is also augmented punting; this is when the vertebrate uses both the pectoral fins and the pelvic fins to generate more thrust, this action decreases the forces on the pelvic fins during a punt. While this locomotion would
Scientists had some idea to the evolutionary process of whales. “It has always been clear that aquatic cetaceans must have evolved from terrestrial mammals and returned to the water, and the forelimbs of recent cetaceans still have the same general pattern as that of land mammals.” (Walking with Whales) It was known fact that land mammals and whales were related. However, the change from ancient whales to modern whales is drastic.
They are the second smartest animal in the world. They nurture their young for most of their lives. They also socialise with any creature, unless they show signs of harm. Dolphins make very popular playmates and will come up to humans for almost anything. They rely on each other to live. They learn quickly and communicate well with one another. God designed dolphins with unique physical features and behaviors in order to glorify Him.
Whales living in captivity become aggravated and have been known to take out anger on themselves by self harming. In the pools they live in, metal bars are placed in between the pools to prevent the killer whales from swimming to another pool. On several occurrences, the whales have attempted to bite and break the metal bars. This leaves the whales with broken teeth and a risk of infection. Infections in killer whales can lead to death in many cases. If a whale gets an infection, they have to be taken out of the pool and placed into another pool by themselves to prevent any problems with other killer whales they live with. In many cases, whales with infections need serious care from whale specialists.
Although it is remarkable that these marine mammals are capable of so much, there are things the public does not know. According to classified statistics, twenty-three out of forty-three animals died while being transported from their natural habitat to foreign aquariums for training. Another thing the public does not know is in reference to a similar marine mammal program in the Soviet Union. It has been reported that Soviet dolphins were trained to do "kamikaze" missions. Explosives were supposedly strapped to their backs and they were sent out to destroy enemy submarines. According to statistics, about two thousand dolphins have died on these, and similar, missions.
A killer whale doesn’t have very many enemies. One of a killer whale's biggest enemies is the human species. Humans have been hunting killer whales since the 12th century; whalers around the world have killed thousands of killer whales. Other threats to killer whales are toxic wastes, oil spills, and garbage in the oceans. Oil spills are extremely dangerous because not only do they damage killer whales, but also they will hurt any thing else in the oceans. Garbage kills ocean life worldwide every year. Currently the threats are
The origin of modern day whales, a mystery that has puzzled paleontologists for years, may have just been solved with the discovery of an ankle bone. This discovery might sound simple and unimportant, but the bones of these ancient animals hold many unanswered questions and provide solid proof of origin and behavior. The relationship between whales and other animals has proven to be difficult because whales are warm-blooded, like humans, yet they live in the sea. The fact that they are warm-blooded suggests that they are related to some type of land animal. However, the questions of exactly which animal, and how whales evolved from land to water, have remained unanswered until now.
Cetaceans are thought to be some of the most intelligent species on this planet. Popular culture has embraced the idea of cetacean intelligence with shows such as the 1960s hit TV series Flipper, where a dolphin is used to help fight crime. In his comedic science fiction novels, the Hitchhiker’s Guide to the Galaxy, author Douglas Adams suggests that dolphins are the second most intelligent creatures on Earth, behind mice and above humans. Although most scientists would probably argue that humans are the most intelligent species, the behavior and brain size of dolphins and other cetaceans suggests that they too are intelligent. This paper will briefly describe the reason some scientists believe cetaceans are intelligent species and then give examples of scientific studies, which suggest cetacean intelligence. Since bottlenose dolphins and orcas are the most widely studied cetaceans, the survey of field studies will primarily focus on these two species. At the end, this paper provides an argument of why some scientists discredit the high degree of cetacean intelligence.
Cold water is the key aspect in the phenomenon called the mammalian diving reflex. This reflex has been beneficially used for thousands of years by whales, dolphins, seals and other mammals that inhabit the frigid waters of the world. The diving reflex slows heart rate and causes peripheral vasoconstriction to keep blood and oxygen to the brain and other vital core organs. This reflex allows these mammals to conserve oxygen and stay submerged over longer periods of time, providing them more time for finding food, protection and travel.
The North Atlantic right whale (Eubalaena glacialis) has had a slow recovery since the cessation of commercial...
Humpback whales breath voluntarily, unlike humans. Since they have to remember to breath, researchers believe humpbacks sleep by shutting off half of their brain at a time. Like orcas and dolphins, humpback whales have noses at the top of their head called blowholes (Animal Planet). Humpback whale calves do not stop growing until they are ten years old (National Geographic). They breed, give birth and care for their newborn calves in the warm waters of Tonga. Instead of teeth, humpbacks have baleen plates, they are brush-like strands of bristle that trap there food until it is swallowed. They have very odd mouths that curve downwards, like an eternal frown. Humpback whales are amazing marine mammals (Big Animal Expeditions)
...r. Even though they live in the ocean all their life and also amusement parks, dolphins are mammals, not fish. That makes them very intersting animals because of all the charactics that they have that people would have never known about. Dolphins are by far the most intelligant marine mammals in the ocean.
Did you know in the world there are more than 90 species of whales, dolphins, and porpoises? (WDC) The dolphin is a very important animal to the ocean and there are many different types to discover. In order to learn about dolphins, it is important to discuss where they live, their appearance, and what they eat. Some helpful words to understand are “dorsal fin”, a dorsal fin is the top pointed fin on the dolphins back, “flippers”, a flipper is a flat fin that dolphins use to swim, and “echolocation” is a tool dolphins use to find food by sounds bouncing off of objects (dictionary.com).