Killer whale

Draft Plan:

• Introduction
• Orcas:
  • Classification
  • Physionomie
  • Habitation and Distribution
    • The different groups
  • Adaptation to this habitation
  • Nutrition
  • Hunting
  • Reproduction
  • Spatial and behavior structure
  • Communication
  • The population growth
• Pollution:
  • Definition
  • Human activity
    • Traffic
    • Farming
    • Hunting
  • Chimical pollution

• Observation of the animal
  • The diefferant technics to observe the animal

Classification: Orcas, Orcinus orca

In common life we give the names of animal according to our own language. However we use a system call binomial nomenclature to have no mal entendu between scientific coming from different language. This is why we use a a scientific language to give names to animals. The binomial nomenclature uses 3 laws. First we say the genus and the specie of the animal in Latin. When we write the scientific name of the animal the first letter of the genus is written in uppercase letter and the hall name is written in italic. The scientific name of the killer whale is Orcinus orca. Each animal is classified in a specify way according to there characteristics. We use for this a system call hierarchic classification.
Here is the hierarchic classification of the Orca:
Domain: Eucaryote
Reign: Animal
Crotch: Stringed
Class: Mammals
Order: Cetacean
Family: Delphinia
Genus: Orcinus
Specie: Orca
Genus, species: Orcinus orca

Morphology

The Orcas as often been merged with a whale because of his extraordinary size. However Orcas are dolphins. The biggest ever known. There other name killer whale can also bring confusion of there real origins which is dolphins.
The size of an orca changes choosing it's sex and also it's geographic location.
Size:

• Male:

When a male orca reaches it's maturity, it can be 9.8 m long. It wises in average 3.6 and 5.5 tone, it can even wise 11t. The back, codal and pectoral fin can be in average 2 meter.

• Female:

When a male orca reaches it's maturity, it can be between 5 and 7.7 meter long. It wises in average an1.3 and 3.6 tone, it can even wise 7.4t. The back, codal and pectoral fin can be in average

• The young:

At the birth the the young measures between 1.8 to 2.7 choosing it's location birth. The weight of the new born is in average 180 kg.

Coloration:
We can easily recognize an Orca because of his distinctive corporal black and white pigmentation.

Body shape:

Habitation and Distribution

The different species

We have 3 different species of killer whales:

• Resident killer whales
• Transient killer whales
• Off-shore killer whales

Reproduction

The Orcas have a close reproduction mode to the non aquatic mammals and including ours.

Spatial and behavior structure

During expedition we can observe that dolphins member and so Orcas are structured as a herd. In fact these animals stay in group together and stay closer to each other than to an animal from an other group. We can observe one or two leaders in the herd and the presence of a constant central group. These leaders are stronger and larger than the others. These dominant member observed the area for potential danger or investigates if there is something new happening near the group.We sometimes have also two or three members of the group that are more in front of the others to watch for inshore areas or danger. When there is a danger the animals immediately regroups there self in a packed group with the youngest in the middle protected by the other members. There movement are synchronize and in harmony. The group structure of orcas allows them a good use of the space around them as for hunting in several different conditions.

+ Herd = family !

References

Dolphin Societies, discoveries and puzzles, edited by Karen Pryor and Kenneth S.Norris
The Ecology of whales and dolphins, edited by D.E.Gaskin
http://www.seaworld.org/infobooks/KillerWhale/home.html

maybe you should start putting all the references somewhere on the wiki...--Pierre.brawand 2 février 2009 à 22:59 (MET)