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ich bin schön sesame الخميس مارس 11, 2010 11:47 pmSTATUS:
Vulnerable.
DESCRIPTION:
The orca, or "killer," whale is the largest member of the dolphin family. Orcas have long, rounded bodies with large dorsal fins at the middle of their backs. Their black bodies are marked with white patches on the underside and near the eyes.
SIZE:
The average male orca grows to 23 feet long and weighs 7 to 10 tons. Females average 21 feet long and weigh 4 to 6 tons.
POPULATION:
The worldwide population of orcas is unknown.
LIFESPAN:
Orcas live 30 to 50 years in the wild.
RANGE:
Found in all oceans of the world, orcas are most common in the Arctic and Antarctic and are often spotted off the west coast of the United States and Canada.
HABITAT:
Orcas are found in both coastal waters and open ocean.
FOOD:
Like dolphins, orcas use echolocation - bouncing sound off of objects to determine their location - to hunt and use a series of high-pitched clicks to stun prey. Orcas feed on fish, squid, birds, and marine mammals. Orca pods often work together to catch a meal. Pods sometimes will force many fish into one area and take turns feeding or will beach (slide out of the water onto the shore) themselves to scare seals or penguins into the water where other whales are waiting to feed.
BEHAVIOR:
Orcas are highly social animals that travel in groups called pods. Pods usually consist of 5 to 30 whales, although some pods may combine to form a group of 100 or more. Orcas establish social hierarchies, and pods are lead by females. The animals are thought to have a complex form of communication with different dialects (slightly different language) from one pod to another.
OFFSPRING:
Orca gestation is 13 to 16 months. A calf is born in autumn weighing almost 400 pounds and measuring up to 7 feet in length. A calf will remain with its mother for at least two years.
THREATS:
Recent studies have found that orcas are among the most contaminated marine mammals in the world. Pollution and chemical contamination make orcas more susceptible to disease and likely cause reproductive difficulties.
PROTECTION:
*CITES, Appendix II, Marine Mammal Protection Act
*Convention on International Trade in Endangered Species of Wild Fauna and Flora, an international treaty with more than 144 member countries. Appendix I species cannot be traded commercially. Appendix II species can be traded commercially only if it does not harm their survival.
Order--Cetacea.
All dolphins, porpoises, and whales are grouped together in the scientific order Cecacea. This large order of approximately 80 living species is divided into three suborders: the toothed whales or Odontoceti (killer whales, dolphins, porpoises, beluga whales, narwhals, beaked whales, and sperm whales), the baleen whales or Mysticeti (blue whales, humpback whales, gray whales, and right whales), and the Archaeoceti (a group of fossil whales, now extinct).
Family--Delphinidae.
Dolphins and their immediate kin are included in the scientific family Delphinidae. This family is represented by about 32 species, including some that have similar sounding names to killer whales such as pygmy killer whales (Feresa attenuata) and false killer whales (Pseudorca crassiddens). Killer whales are the largest member of the dolphin family.
Genus, species -- Orcinus orca
1. Because of their fierce reputation, killer whales are sometimes called ballena asesina ("assassin whale") by the Spanish. They were referred to as "whale killers" by sailors who witnessed their attacks on larger cetaceans, an over time this name was changed to "killer whales". They are called this not because they harm humans but because they kill other whales.
2. Some researcher believe distinct species of killer whales exist, especially in the Antarctic. The majority of scientists, however, group killer whales as a whole and label them all as Orcinus orca. Orcinus is probably derived from Orcus, an ancient mythological Roman god of the netherworld -- a reference to the ferocious reputation of this animal. Orca literally means "the shape of a barrel or cask" in Latin, likely due to the killer whale's body shape.
Fossil Record.
1. The classification of whales puzzled early researchers even though cetaceans roamed the ocean long before recorded history. Modern forms of both odontocetes and mysticetes appear in the fossil record an estimated five to seven million years ago. Some believe the early whales arose 55 to 65 million years ago from (now extinct) ancient land mammals that ventured back into the sea. One such extinct creature may have been Ambulocetes natans. Ambulocetes natans was discovered in Pakistan and fossil remains show a legged land animal that also feature several characteristics of whales.
2. Numerous large fossilized teeth, primarily from the Pliocene (two to five million years ago), are thought to be those of O. orca or a closely related species. One such species, O. citoniensis, is an extinct whale that had a higher tooth count and smaller size compared to modern killer whales.
3. Because whales spend their entire lives in water, they were wrongly classified as a type of fish in ancient days. Finally the Greek philosopher Aristotle (384-322 BC) correctly classified whales as mammals in his book Historia Animalium. A killer whale has more in common with a human than with a fish as both a whale and person share similar mammalian characteristics. For a example, a fish is unable to control its body temperature. A mammal, such as a whale, maintains a constant body temperature independent of its environment. Killer whales have a high body temperature similar to that of humans.
Vulnerable.
DESCRIPTION:
The orca, or "killer," whale is the largest member of the dolphin family. Orcas have long, rounded bodies with large dorsal fins at the middle of their backs. Their black bodies are marked with white patches on the underside and near the eyes.
SIZE:
The average male orca grows to 23 feet long and weighs 7 to 10 tons. Females average 21 feet long and weigh 4 to 6 tons.
POPULATION:
The worldwide population of orcas is unknown.
LIFESPAN:
Orcas live 30 to 50 years in the wild.
RANGE:
Found in all oceans of the world, orcas are most common in the Arctic and Antarctic and are often spotted off the west coast of the United States and Canada.
HABITAT:
Orcas are found in both coastal waters and open ocean.
FOOD:
Like dolphins, orcas use echolocation - bouncing sound off of objects to determine their location - to hunt and use a series of high-pitched clicks to stun prey. Orcas feed on fish, squid, birds, and marine mammals. Orca pods often work together to catch a meal. Pods sometimes will force many fish into one area and take turns feeding or will beach (slide out of the water onto the shore) themselves to scare seals or penguins into the water where other whales are waiting to feed.
BEHAVIOR:
Orcas are highly social animals that travel in groups called pods. Pods usually consist of 5 to 30 whales, although some pods may combine to form a group of 100 or more. Orcas establish social hierarchies, and pods are lead by females. The animals are thought to have a complex form of communication with different dialects (slightly different language) from one pod to another.
OFFSPRING:
Orca gestation is 13 to 16 months. A calf is born in autumn weighing almost 400 pounds and measuring up to 7 feet in length. A calf will remain with its mother for at least two years.
THREATS:
Recent studies have found that orcas are among the most contaminated marine mammals in the world. Pollution and chemical contamination make orcas more susceptible to disease and likely cause reproductive difficulties.
PROTECTION:
*CITES, Appendix II, Marine Mammal Protection Act
*Convention on International Trade in Endangered Species of Wild Fauna and Flora, an international treaty with more than 144 member countries. Appendix I species cannot be traded commercially. Appendix II species can be traded commercially only if it does not harm their survival.
Order--Cetacea.
All dolphins, porpoises, and whales are grouped together in the scientific order Cecacea. This large order of approximately 80 living species is divided into three suborders: the toothed whales or Odontoceti (killer whales, dolphins, porpoises, beluga whales, narwhals, beaked whales, and sperm whales), the baleen whales or Mysticeti (blue whales, humpback whales, gray whales, and right whales), and the Archaeoceti (a group of fossil whales, now extinct).
Family--Delphinidae.
Dolphins and their immediate kin are included in the scientific family Delphinidae. This family is represented by about 32 species, including some that have similar sounding names to killer whales such as pygmy killer whales (Feresa attenuata) and false killer whales (Pseudorca crassiddens). Killer whales are the largest member of the dolphin family.
Genus, species -- Orcinus orca
1. Because of their fierce reputation, killer whales are sometimes called ballena asesina ("assassin whale") by the Spanish. They were referred to as "whale killers" by sailors who witnessed their attacks on larger cetaceans, an over time this name was changed to "killer whales". They are called this not because they harm humans but because they kill other whales.
2. Some researcher believe distinct species of killer whales exist, especially in the Antarctic. The majority of scientists, however, group killer whales as a whole and label them all as Orcinus orca. Orcinus is probably derived from Orcus, an ancient mythological Roman god of the netherworld -- a reference to the ferocious reputation of this animal. Orca literally means "the shape of a barrel or cask" in Latin, likely due to the killer whale's body shape.
Fossil Record.
1. The classification of whales puzzled early researchers even though cetaceans roamed the ocean long before recorded history. Modern forms of both odontocetes and mysticetes appear in the fossil record an estimated five to seven million years ago. Some believe the early whales arose 55 to 65 million years ago from (now extinct) ancient land mammals that ventured back into the sea. One such extinct creature may have been Ambulocetes natans. Ambulocetes natans was discovered in Pakistan and fossil remains show a legged land animal that also feature several characteristics of whales.
2. Numerous large fossilized teeth, primarily from the Pliocene (two to five million years ago), are thought to be those of O. orca or a closely related species. One such species, O. citoniensis, is an extinct whale that had a higher tooth count and smaller size compared to modern killer whales.
3. Because whales spend their entire lives in water, they were wrongly classified as a type of fish in ancient days. Finally the Greek philosopher Aristotle (384-322 BC) correctly classified whales as mammals in his book Historia Animalium. A killer whale has more in common with a human than with a fish as both a whale and person share similar mammalian characteristics. For a example, a fish is unable to control its body temperature. A mammal, such as a whale, maintains a constant body temperature independent of its environment. Killer whales have a high body temperature similar to that of humans.