Introduction
The Order Cetacea is one of the most distinctive and highly specialized groups of mammals. Over the course of evolutionary history, cetaceans have become adapted to surviving and prospering in a vast aquatic environment. One of the most important obstacles they have overcome is the ability to be obligate ocean dwellers while still breathing oxygen. Cetaceans are able to remain underwater for extended periods of time, returning only to the surface to exhale. Diving beneath the surface is an essential component of life for these species since almost all of their food sources are found under the surface of the ocean.
One of the most-well known diving cetaceans is the sperm whale (Physeter macrocephalus). The world’s largest carnivore, this massive cetacean makes extremely deep dives for food, mainly squid and octopus, but also fish and sometimes giant squid (Burnie and Wilson 2005). Sperm whales can dive to depths of 400 to 1200 meters, and for durations of up to 138 minutes (Watwood et al. 2006). The majority of sperm whale dives have been reported to last from 33 to 53 minutes (2006). Sperm whales have to overcome several fundamental problems while diving at such great depths: the effects of pressure and the need to actively forage while holding their breath. Adaptations to pressure have to deal with the mechanical effects of pressure and the increased solubility of gas at depth (Costa 2007). Adaptations to breath-holding diving center around modifications in metabolism, blood flow, and an increased oxygen storage capacity (2007).
Effects of Pressure
As sperm whales dive, they must deal with the direct effect of pressure that is associated with the volume change of air-filled spaces in their bodies. Changes in air v...
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Keeping these huge animals in small pools does not seem right. Big mammals are not meant to be in small pools. When these mammals are born they stay with there mother all of their lives. They never leave their mothers until they are captured and put in small pools which is not right. Killer whales hunt in pods, the oldest female in the pod is usually the group leader. Each pod has its own set of whistles, clicks, and calls that only members of the pod recognize similar to having a unique language. Members of many pods hunt in teams. For example, they may work together to create waves to knock a seal from an ice floe and into the open water. In many pods,...
Blackfish: The Documentary Entertainment is a word that invokes feelings of fun and pleasure. It is an exciting time with family and friends filled with joy and laughter, especially at amusement parks. However, what about the whales entrapped at water parks? How do they feel about this? Are they content with their environment?
This has been a tradition of the Makah Indians for more than 2000 years. They had to stop in 1926 due to the scarcity of gray whales. But their abundance now makes it possible to resume their ancient practice of the hunt.
Today, we see much less of an obvious relationship of the cetaceans to the terrestrial mammals.
While whaling isn’t nearly as popular today, in this time many men made, or attempted to make, a living in this industry. Despite the hard work, dangerous standards and general intimidation, shipmates were lured into the industry for the high pay. When feeling protected by a large ship, weapons and a fearless captain, it was easy to forget the power of what they were hunting. The sperm whale is the largest of all the toothed whales, with males maturing at an average size of fifty- two feet and sometimes can reach up to sixty-seven feet in length. “It’s twenty-foot-wide tail pumped up and down.” (Philbrick, 2000, 82) The domain of life that the sperm whale belongs to is the Eukaryote. This is because the sperm whale is an organism that is made up of cells that contain a nucleus as well as other structures that are enclosed by the cell membrane. The kingdom that it belongs to is the Animalia. This is because they are multi-cellular organisms. These animals contain other distinct features including; “interior digestion of f...
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.
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.
For this experiment, it is important to be familiar with the diving reflex. The diving reflex is found in all mammals and is mainly focused with the preservation of oxygen. The diving reflex refers to an animal surviving underwater without oxygen. They survive longer underwater than on dry land. In order for animals to remain under water for a longer period of time, they use their stored oxygen, decrease oxygen consumption, use anaerobic metabolism, as well as aquatic respiration (Usenko 2017). As stated by Michael Panneton, the size of oxygen stores in animals will also limit aerobic dive capacity (Panneton 2013). The temperature of the water also plays a role. The colder the water is, the larger the diving reflex of oxygen.
Before commencement of the diving reflex, three critical changes have to occur to the body in order to stimulate the diving reflex. First to occur is change in the heart rate, this occurs immediately when the face has contact with cold water the human heart rate slows down ten to twenty-five percent. Seals for example undergo extreme changes in their heart rates, from going approximately 125 beats per minute to as low as 10 on a lengthened dive. (Arterial gas tensions, 1989). By slowing the heart rate it reduces the need for bloodstream oxygen, dispensing more to be utilized by other vital organs. Following the heart rate changes peripheral vasoconstriction sets in, which is the narrowing of blood vessels to reduce blood flow and is achieved by a muscular contraction in the blood vessel walls. This decreases the amount of blood that flows to peripheral organs in which do not need a high level of oxygen to function. This is the prevention of blood circulation to certain areas, first to close off are the Toes and fingers, then hands and feet, and ultimately arms and legs. The constriction allows for more blood for use by the heart, brain and organs. Lastly, the blood shift that occurs only during very deep dives. When this happens organ and circulatory walls allow plasma and water to pass freely throughout the thoracic cavity, so its pressure stays constant and prevents the organs from being crushed. In this stage, the lungs' alveoli fill up with blood plasma, which is reabsorbed as soon as the animal leaves the pressurized surrounding. This stage of the diving reflex has been observed in humans such as deep diving scuba divers, who can reach distances of approximately 90+ metres. Therefore, both a conscious and an unconscious pers...
Orcas, or killer whales are majestic giants of the sea. They are actually the largest type of dolphin. They have long black bodies with distinct white patches near their eyes. A killer whale can be up to 32 feet or more in length, and weigh up to 12,000 pounds. Females are a bit smaller, but live longer (Gorman). The name “killer whale” apparently came not because it is a vicious whale, but because it preys on whales. They do not have any natural predators, and they are considered the “top dog” of the ocean. Not even the great white shark stands a chance against these superb killers. “Unlike sharks, killer whales are cautious hunters, sometimes spending hours harassing a 1,000-pound sea lion so it can easily be drowned” (Francis). Orcas use many hunting tactics that are unique to their species, which is what makes them invincible.
In recreational scuba diving there is a laundry list of available equipment to fit nearly every underwater need. One of the most important pieces of equipment a recreational diver uses is the BCD or buoyancy control device. The BCD is an adjustable inflation vest worn by a diver to increase or decrease their buoyancy during a dive. The BCD is hooked to the regulator or “Octopus” which serves as a junction point for air accessories. The BCD usually comes complete with safety features like an emergency dump valve. Safety features like these help to prevent BCD malfunctions, such as runaway accents, by allowing the diver to release the air out of the vest. Attached to the regulator along with the BCD are air pressure gauges and two breathing apparatuses. One breathing apparatus is used for normal breathing function and the other is set in a known location in the case of an emergency or disorientation. Recreational divers also have a choice between wearing a neoprene wet suit, which keeps a diver warm by retaining a layer of water next to the body, or dry suits that use a layer of air for buoy...
“In life, sharks are very flexible. Even hammerheads and large ocean sharks are quite flexible,” Lauder said. “If you watch a shark swim, the head does not move very much, so it could be that the denticles on the head are mostly reducing drag, but those on the tail are enhancing thrust. But we don’t know what that balance may be. Ultimately, though, one of the key messages of this paper is that shark skin needs to be studied when they’re moving, which hadn’t been done before.”
...d insulates the body. Whales have a spinal column, a vestigial pelvic bone, and a four-chambered heart. The neck vertebrae are typically fused, trading flexibility for stability during swimming. ("Whale." Wikipedia. Wikimedia Foundation, 13 May 2014. Web. 15 May 2014).
The Humpback Whale, Megaptera novaeangliae, is part of the marine mammals group. They are found in oceans all over the world, they live in open waters. Even though they are mammals, they do not live on land (Monterey Bay Aquarium). Humpback whales are known for their magical song that can travel great distances. These gentle giants are omnivores, their main diet is krill. They are mostly found near coastlines feeding on tiny shrimp-like krill, plankton and small fish. Humpbacks migrate annually from summer feeding grounds near the poles to warmer winter breeding water closer to the Equator. Humpback whales are powerful swimmers, and they use their massive tail fin, called a fluke to propel themselves through or even out of the water! Mothers and their young swim close together, often touching one another with their flippers with what appears to be gestures of affection. Even though it takes more than one year for a humpback whale to grow fully, mother whales leave them after one year (National Geographic).
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).