Whale by Lovejot Singh
Whales are one of the many mammals that have evolved to inhabit marine waters. There are approximately 80 species of whales that are divided into two categories: toothed and baleen. Baleen whales have two blowholes, use echolocation mainly for communication, and generally consume small prey such as plankton. On the other hand, toothed whales have one blowhole, use echolocation to find prey, and seek out larger prey. Despite these differences, most physiological processes among whales are basically the same (5).
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Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Cetacea |
Physiological Differences Related to Respiration
Many people make the mistake in thinking that whales have gills. Whales are mammals, not fish. This means that like all land mammals, they breathe oxygen using lungs. They do this through their blowholes which are actually nostrils that have moved to the top of their head over many, many years. Unlike most land mammals, whales have completely voluntary breathing. They have to choose when to breath. Whales can remain underwater anywhere from 7 to 120 minutes. This is due to a couple of factors. First, whales are able to slow their heart rate when they dive (bradychardia). This reduces the amount of oxygen that is used (2). Next, whales have a high amount of myoglobin in their muscles. Myoglobin is a protein similar to hemoglobin, but it has a higher affinity for binding oxygen (7). Also, the lungs in whales are able to collapse when they dive. This prevents them from rupturing (5). Lastly, whales absorb 90% of the oxygen that they take in. This is a large percentage considering humans only absorb about 15%. All of these reasons enable whales to make the most of each breath they take and to remain submerged underwater for long periods of time (9).
Respiratory Processes
- The whale comes to the surface of the water and muscles around the blowhole contract to open it, the diaphragm contracts, and carbon dioxide is exhaled.
- Fresh air is inhaled as the diaphragm relaxes and the muscles around the blowhole relax, closing it.
- The air travels through the nasal passages, pharynx, larynx, trachea, and finally to the lungs.
- Oxygen is transported into the blood stream via capillaries found in sacs in the lungs.
- The heart pumps the blood with the oxygen to the bodies extremities.
- Carbon dioxide is returned to the lungs and the process repeats itself (2, 5, 6).
Relating Article
Killer Whales Facing an Airborne Threat
An article was published fairly recently in The Seattle Times bringing to light new research on whale illness associated with airborne pathogens. Researchers have found that the air that a whales breathe in contains many pathogens more commonly found in land environments and that many whales have died of pneumonia, a severe respiratory illness. This has sparked concern that widespread infections could pose a threat to many species of whales. Research such as this is important in order to maintain the health of whale populations and ecosystems in general (8).
An article was published fairly recently in The Seattle Times bringing to light new research on whale illness associated with airborne pathogens. Researchers have found that the air that a whales breathe in contains many pathogens more commonly found in land environments and that many whales have died of pneumonia, a severe respiratory illness. This has sparked concern that widespread infections could pose a threat to many species of whales. Research such as this is important in order to maintain the health of whale populations and ecosystems in general (8).
The following video gives an up close look at the behavior, use of echolocation, and breathing habits of humpback whales.
Did You Know ?
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Whales only sleep with one side of the brain at once. This is due to the fact that they are conscious breathers. If they rested both sides of the brain at once, they wouldn't go up for air and they would suffocate (4).
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