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or Killer Whales
Orcas, or Killer
Whales (Same creature), are highly intelligent and very curious
mammals. Orcas are the most widely distributed of
any marine mammal on Earth, being found in all
oceans from cold polar seas to tropical waters.
Orcas live in a very organized family unit called a
pod that includes several generations. Unusually
curious about the visitors in their waters, they may
approach boats in order to get a better look at the
human visitors. Their acrobatic skills are seen as
they spy-hop, tail-slap or breach the water as this
juvenile Orca is doing.
Often referred to as Killer Whales, the name "Orca"
has been gaining popularity, however both are
correctly interchangeable. In the past, Killer
Whales have also been called Sea Wolves, Wolves of
the Sea and blackfish. These names are closer
related to the folklore and tales of the sea that
were told by sailors and fishermen.
Orcas belong to the Oceanic Dolphin family. They
have a mainly black back, white jaw, chest and
sides, a white patch above and behind the eye and a
"saddle patch" straddling across the back directly
behind the dorsal fin
Orcas are large marine mammals, measuring from 20 -
26 ft (6 - 8 m) long and weighing 13,000 lbs (6,000
kg) with females being slightly smaller. Another
major distinction between the sexes is the males’
large dorsal fin that stands straight up and can
reach up to 6 1/2 ft (2 m) tall.
Female Orcas live a relatively long life, reach an
average ago of 50 years, while the males are not so
lucky. The average lifespan of a male Orca is only
29 years. There have been exceptional cases where 90
year old females and 70 year old males have been
recorded. Lifespan of captive Orcas however, those
performing in tanks and aquariums, however is much
shorter with an average lifespan of only 20 years.
Although there has been extensive studying, research
and published information relating to the Killer
Whales of the Pacific Northwest, there is a much
larger population existing in the Antarctic waters.
Globally, all Orcas have a diverse diet, however
different geographic population groups have evolved
to specialize in hunting particular prey.
In the Pacific Ocean and Pacific Northwest there are
three distinct groups of Orcas, the transient,
resident and offshore groups. “Resident Orcas” are
primarily fish eaters, with diets consisting mainly
of fish and squid. They are known to visit and
return to the same areas regularly. “Transient
Orcas” prey primarily on marine mammals and do not
eat fish. They travel extensively along the coast
and live in smaller family groups than residents.
“Offshore Orcas” travel far offshore into open ocean
waters and are believed to eat mainly schooling
fish. DNA studies have shown them to be genetically
removed from the other two types of Orcas but little
is known of them.
Additionally, there are another three different
Killer Whale types documented in the Antarctic
waters. It is these variance characteristics along
with differences in coloration, social structure,
interactive behaviors and other factors are leading
researchers to believe that there are several
different and unique genetic strains of orcas and,
with further study, the Orcas may be broken down
into additional distinctive groups.
Killer Whales are regarded as apex predators with no
natural enemies. With good eye sight, both above and
below the water, excellent hearing, extensive use of
echolocation (like sonar) to locate prey and the
ability to swim at speeds in excess of 35 mph (56
km/h), they are at the top of the aquatic food chain
|The Orca does however have one devastating enemy -
environmental pollution. Orcas appear to be very
closely “in tune” with their environment and react
very drastically to major upsets and changes.
Following the Exxon Valdez oil spill in Prince
William Sound, Alaska, the AT1 pod of Orcas,
estimated at one time to include 346 orcas, was
decimated until there were only 7 family members
left. It is believed that this group is unable to
reproduce and will become extinct.
Orcas are the most widely dispersed marine mammal.
They are found in every ocean of the world,
including the warm waters of the Mediterranean and
the Arabian Sea, however they do prefer cooler
temperatures and polar waters. Orcas are migratory
animals; however, their migratory patterns are
poorly understood. While the same Resident Orcas may
be spotted every year in the summer in the Northwest
Pacific, it is not clearly understood where they
migrate and venture to during the winter.
Females give birth to a calf on average once every 5
years, with winter being the most common birthing
season. Calves weigh about 400 lbs (180 kg) at birth
and measure 7 ft (2 m) long. Orcas mothers’ milk
contains almost 50% fat, is pink in color and will
feed the calf for the next 12 months. Following
birth, the Orca calf will begin consuming almost 100
lbs (45 kg) of this nutrient packed milk. For the
next 12 months, they feed from their mother and will
be fully weaned after 24 months.
Orcas are highly social, with tight groups comprised
of family members with a female as the head of the
family. Only higher primates (such as humans),
elephants and orcas live in such complex social
structures. It is noted that North Pacific resident
Orcas have a particularly complex family structure,
with all the animals in the family living with their
mother for their entire lives. The family structure
is based on matrilines with the mother being the
matriarch of the group. On average, up to 4
matrilines (families) will group together and form a
pod. Pods may split apart into their own family
groups for weeks or months but eventually come
Orcas are very intelligent and curious animals. They
use many techniques to learn of their surroundings
including spy-hopping. Spy-hopping involves sticking
their heads straight above the water in order to see
and look around the above water surroundings.
Techniques learned and problems solved by orcas are
passed on and "taught" to other members of the pod.
They also appear to be fond of entertaining us by
breaching, that is, jumping completely out of the
water and crashing back down created a huge splash!
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