Bowhead Whales: A Genetic Analysis

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.

Do you know what the biggest animal ever to live on Earth is? You would be wrong if you speculated a dinosaur, elephant, or giraffe. You may be surprised to find out that the biggest animal ever to live on Earth is the Blue Whale and it is still alive today. The Blue Whale weighs as much as 33 elephants and consumes about 4 tons of food a day. I bet if you knew of an animal that was as long as 3 school buses you would want to keep this animal in the world forever. Although, the Blue Whale may not stay for long, many things affect the blue whale’s inhabitance, mainly the acts of humans have caused the Blue Whale’s to become endangered. Though, if you know the information about them you can help.

Whales are large aquatic mammals. Like every other animal they did not start off like that. Whales came to be after millions of years of evolution. Every aspect of the current whale was decided by nature. The blowhole, dorsal fins, lack of teeth and tail fluke all came from years of other creatures such as the Mesonychids and many other animals.

The ocean is a vast biome that is constantly changing. There is much to learn about the life within, the article “Omura's whales (Balaenoptera omurai) off northwest Madagascar: ecology, Behavior and conservation needs” showed how our knowledge of the ocean and the life within continues to grow. Balaenoptera omurai, or Omura's whale was only found as a new species in the year 2003. Their are no dependable population size estimates or evaluation of conservation facts because there is not enough data collected on these cetaceans. Scientists are able apply what they learn from some of these organism to humans. In the article “Reproductive Conflict and the Evolution of Menopause in Killer Whales” scientists were able to draw comparisons between Humans and other species.

In the article, “Sperm Whales and Killer Whales with the Largest Brain of All Toothed Whales Show Extreme Differences in Cerebellum” the author Sam H. Ridgway studies the cerebellums of the most widest distributed whales in the world. The killer whale and the sperm whale both have huge brains, but this study suggests why the killer whales have a significantly larger cerebellum than that of the sperm whale. After collecting, measuring, and preserving the species, the skull was ready to be chipped away and the brain ready to be taken from the massive cranium. Once extracted, the brain was measured to determine the cerebellar volume: (length of cerebellum base × width of the base × height × 1/3).

Western Pacific whales are rather rare, with the California gray whale recently removed from the endangered list and the western Pacific whale having as few as 150 individual whales remaining rendering it critically endangered. A new study has emerged questioning whether western Pacific whales are really a separate population or simply California gray whales that have expanded their feeding grounds.

The earliest whales were land animals with long skulls and carnivorous teeth. Analysis of whale skulls showed major morphological changes, including changes to the skull size, shape, teeth, and nostrils. Fossil evidence shows that the trait of interest, the nostrils, can be found on fossils of the earliest whales, dating back to about 50 million years ago. Evolution occurred multiple times since then, each time resulting in the nostrils migrating further back on the skull. Eventually, the pair of nostrils positioned itself right on top of the head. These nostrils are the blowholes we see positioned on top of modern whales today. In addition, another momentous change in the nostrils occur when order Cetacea splits into Mysticetes and Odontocetes. Suborder Mysticetes

Killer whales were first captured and separated from their family group (pods) to be put display for the public 1964. After years of research in their natural habitat and at marine parks throughout the world, it has become obvious that they belong in the ocean and not kept in captivity (Rose). The stress that killer whales feel at being kept in tanks for the general public’s amusement changes their natural behavior and makes them a danger to anyone who has direct contact with them. I feel that after so many years of having marine biologists and veterinarians studying these animals in captivity that little can be left to learn about the killer whales to justify breeding killer whales and keeping them in marine parks.

Today, I will talk about the problem of keeping whales in captivity and how to overcome it.

Some evolutionists claim whale ancestors were originally land mammals. Though many people refute this claim, there is much evidence. First is the Indohysus. The Indohysus was discovered to share a thickened bone that helps with hearing underwater with modern whales. The Indohysus also had denser bones, which meant it was partially aquatic. Next is the Pakicetus; the Pakicetus also had very dense bones, indicating it was semi-aquatic. The Pakicetus was similar in structure to a wolf, but the skull had eye sockets that were adapted for looking upwards, most likely at objects or animals floating above it. The Ambulocetus was found to have reduced limbs and an elongated skull and reduced limbs; it most likely spent most of its time in the water.

I picked the killer Whale, also known as Orcas for this assignment. Orcas are cultural creatures. Scientist have observed three main groups of Orcas evenly distributed throughout the ocean. The three groups have vastly different diets, languages, hunting techniques and manners of behaving around other marine life. The groups do not seem to interact much with one another. Orcas pass down specific behavior thought to each other from generation to generation. Orcas often hunt in groups and orchestrate their strategies perfectly with each group member having specific tasks.

1) In 2009, a captive beluga whale rescued a diver during a free-diving competition. 2. Belugas are gregarious and live in social groups of 2-25 individuals (the average group size is ten). 3. Belugas are unique among cetaceans in that the vertebrae in their necks are not fused together. This gives their heads added manueverability.

Orcas biological history entails high endurance for hunting expeditions, traveling hundreds of miles a day in the wild. Aisling Cronin, animal rights activist, pointed out in Killer Whales Don’t Belong in Captivity that, “In the wild, orcas can swim up to 100 miles per day – a phenomenal amount, in comparison to the exercise they receive in captivity” (Cronin, 1). Orcas travel with the sole purpose of hunting. In nature, they hunt on fish and seals. Again, due to lack of exercise, Orcas body structures adapt to conserve energy by decreasing the mass of some muscles.

The average amount of time it takes for a female whale to have a baby varies depending on its species.

Over the millions of years, whales have adapted key traits to stay alive and best natural selection. The forelimbs of whales are modified into flippers, and the hind legs are reduced to internal vestiges. The tail is flattened into horizontal flukes and is used for propulsion. The head is very large, with a wide mouth and no external neck. Whales have one or two nostril openings, called blowholes, located far back on the top of the head; the nostril valves close and the lungs compress when the whale dives. Most whales must surface every 3 to 20 min to breathe, but some, can remain submerged for more than an hour. Whales have small eyes, designed to withstand great pressures, and most species have good vision. Their hearing is also excellent.