Humpback Whales: Endangered Mammals of the Ocean

The Humpback Whale, scientifically named, Megaptera noveangliae, is often thought of as a giant fish. In fact, the Humpback Whale is a mammal. This means that the Humpback Whale has a spine, or vertebrae, is warm blooded, it breathes air and bears live young that it nurses with its own milk. Although the Humpback Whale breathes air and needs oxygen for survival, it cannot live outside of the water.

Humpback Whales are in the sub-order of Baleen Whales. This means that instead of having teeth, Humpback Whales have what are known as baleen plates on either side of their jaw. These plates are made of keratin; the same material that a human's hair and nails is made of. The baleen plates are fringed with hairs along their inner edges and descend downward from the Humpback Whale's upper jaw. Baleen plates are very thin, being only 1/5 of an inch thick. Baleen Whales also have blowholes with two openings. This type of blowhole creates a v-shaped spout when the Humpback comes to the surface to breathe. The spout is what results when air is forced out of the blowhole as condensation.

The Humpback Whale reaches 35-48 feet in length weighs approximately one ton per foot by adulthood. The front flippers are generally about 1/3 of the Humpback Whale's entire body length, reaching up to 15 feet long. The size of these giant flippers is the reason for the scientific name Megaptera noveangliae, as it literally means, "giant wings"

Humpback Whales can be found all over the world in the oceans and seas, but they prefer to remain nearer to the shore because those habitats provide for better feeding and easier breeding. In the summer months, the Humpback Whale feeds in the polar waters, and in the winter months, they travel to sub-tropical or tropical waters for the purpose of breeding and giving birth, during this time, the Humpback Whale does not feed at all. Overall, the Humpback Whale travels approximately 6,000 miles in one year.

When the time comes for the Humpback Whale to feed, they travel to the polar waters. Rather than stalk their prey. The Humpback Whale opens its mouth to take in huge amounts of water; up to 500 gallons at a time. As the water enters the Humpback Whale's mouth, the baleen plates act as filters. The water goes right on through the plates and the food in caught within them. A Humpback Whale's food consists of small fish and Krill, or small shrimp-like creatures. Once the water has all been swallowed, the Humpback Whale uses its tongue to move the food from it baleen plates and swallow it. In a typical day, the Humpback Whale consumes enough food to equal 5-20 percent of its own body weight. Of this food, 25% is stored as fat for warmth and reserve for the winter months of fasting.

A Humpback Whale becomes reproductively mature between the ages of 4 and 8 years. They mate during the winter months and a year later, they give birth to one baby, known as a calf. At the time of birth, a Humpback Whale calf is already 13 feet long and weighs about two tons. The mother Humpback Whale feeds the calf approximately 100 pounds of milk each day for 5 to 7 months before the calf is weaned. By the time the calf is weaned, it is about 27 feet long and weighs 10 tons. The maximum rate of reproduction for the Humpback Whale is one calf per year. This is not typical, however; because it puts too much strain on the female's body. More typically, a female Humpback Whale will have one baby, or calf, every two or three years. The average lifespan of a Humpback Whale is 30 to 40 years. Given this information, and the age of reproductive maturity, the female Humpback Whale will have approximately 18 calves in its lifetime.

Humpback Whales are very acrobatic creatures. They got their name because of the way their back arches when they dive into the water. One of the most beautiful acrobatic acts a Humpback Whale performs is known as breaching. This is when the whale leaps upward out of the water, lifting close to 2/3 of their body completely out of the water. When the breaching height is reached, the whale will often twist its body sideways. This act is believed to be either simple playfulness or an act of courting a whale of the opposite sex. Another behavior is known as head-lunging. This is when the whale thrusts its head forcefully towards another whale. This is believed to be an aggressive behavior used to ward of competition for a mate. Generally, the males are the ones to display this action when they want a specific female as their mate. There are many other acrobatic acts that the Humpback Whales display, however; the purpose for them is unknown.

Male Humpback Whales are known for singing during the breeding season. These songs seem to be similar within specific areas and season, however; they also seem to change from season to season. It is believed that the male Humpback Whales sing to attract mates, or to communicate with the other males in the pod.

A pod is a small social group of Humpback Whales. Pods are generally small in size, consisting of only 2 or 3 whales, rarely up to 15 whales belong to the same pod. It is believed that whale only belong to a specific pod for a short amount of time before moving on to another pod. One specific type of pod that has a low number of whales is called the cow-calf pod. In this pod-type, the mother, or cow, remains with her baby or calf for a year while she is still nursing. One additional adult whale is part of the pod, and is known as an escort. Escorts can be either male or female, but most generally are male. The escort only remains with the cow-calf pod for a few hours before moving on to another pod. For the first full year, different whales seem to become escorts for the cow-calf pods every few hours. To date, there has not been any pod sightings that include more than one calf. This leads us to believe that a calf gets plenty of attention during its first year of life.

Sadly, these magnificent creatures are endangered. Commercially, Humpback Whales are hunted for oil, meat and whalebone. Most populations of Humpback Whales were drastically reduced in the 19^th century. Only 5-10 percent of the original number remains. It is estimated that the Humpback Whale population in the North Pacific was close to 15,000 before 1900. That number was decreased to only 1,000 before 1964, when an international ban on commercial whaling was put into effect. Today, that number is only just above 2,000. There is only one other whale in the baleen species considered to be more endangered than the Humpback Whale.

Aside from commercial whaling for profit and whaling for scientific research, other thing greatly effect the Humpback Whale population. Driftnets and gillnets thrown out into the waters with the intent of catching fish have caused many Humpback Whales to die. The whales cannot detect the nets underwater, and as a result, they unknowingly swim directly into them and become entangled.

Marine pollution is also a cause of the decline in the Humpback Whale population. Contamination that runs into the ocean from rivers, waste left on the beaches to be taken by the waters and deliberate dumping into the ocean, all contribute to the marine pollution that is causing the decline in the population of Humpback Whales and other marine life. Some of the other marine life that is affected causes a lack of food for the Humpback Whales.

Another contributing factor, one that is less thought of, is whale watching. This industry is seemingly harmless because people are not physically harming the mammals, they are merely watching them. However, the boats used to go out onto the ocean for the purpose of watching the whales can pollute the water, and in rare instances, the boat may accidentally hit one of these whales and fatally injure them.

The Federal Government has taken steps to help protect the Humpback Whales and prevent their extinction. In fact, there are very specific regulations on how to approach a Humpback Whale in the Hawaiian waters. For example, it is illegal to operate any aircraft within 1,000 feet of a Humpback Whale, meaning if there are Humpback Whales near the islands, any aircraft must remain 1,000 feet away so as not to disturb the mammal. Another example is a law stating that a person cannot get within 100 yards of any Humpback Whale, and no closer than 300 yards from a mother Humpback Whale and her calf. This law includes approaching a Humpback Whale by any means including in a boat and even swimming. It is also illegal to disrupt any normal activity or behavior of the Humpback Whale. In other words, if the Humpback Whales are playing in the water, breaching, or doing anything else, they are to be left alone. There are strict penalties for anyone caught breaking the laws of the Hawaiian waters.

Internationally, the Humpback Whales are protected from being hunted through agreements made by the International Whaling Commission. Some of these agreements include prohibiting the sale or trade of any parts of the Humpback Whale. There are currently over 120 nations that have signed and agreed to this provision.

Overall, the Humpback Whale is a magnificent creature whose survival largely depends upon our actions. In order to preserve their lives for future generations, we must all work together to keep them safe. We must give them the time they need to reproduce and rebuild their population to the numbers they once were. In order to do that, we must all be aware of the dangers we pose to the Humpback Whales each day and be more mindful in our actions. Through Federal and International Laws, and our own individual efforts, this once abundant species can thrive once again.

Sources for this article include:

http://earthtrust.org/wlcurric/whales.html

http://marinebio.org/species.asp?id=39