Species of the Week: Killer whale

Species of the Week:
Killer Whale or known as Orca(Orcinus orca)

1) Despite popular belief killer whales are not actually whales but belong to the dolphin family and more specifically the oceanic dolphin family.

2) Killer whales have a highly complex social system that is governed by a matriarch. First is the tight knit matriline group which is the matriarch and her offspring.  Then around 1-5 matrilines form a pod which although forages together, pods may break up for certain time periods up to months.  Finally are the clans which is a collection of pods which share the same vocalization, ranges and some older ancestors.

3) There are four types of killer whales:

• Type A: Usually found in the Antarctic, these orcas feed mostly on cetaceans( whales and dolphins) and have a large black and white pattern.
• Type B: They are called the ice pack orca. They feed on seals in the Antarctic and their eye patch is usually large with a two tone grey scale color.
• Type C:  They are called "Ross Sea killer whales". They are the smallest of the orcas and they feed on fish.
• Type D:Transient animals that are usually found in Alaska. They are similar looking to Type A and they feed on all sorts of marine mammals. They are however genetically distinct than  Type A.

4) The average life span of a female is about 50 years while the average life span of a male is around 35 years.

5)Gestation period lasts for 15 to 18 months but the calf usually stays with its mother until the age of two.

6)Different killer whales in different regions have developed their own unique ways of hunting. For example the killer whales in New Zealand have developed the use of bubbles to turn stingrays upside down and eat them while killer whales in the Antarctic have developed the use of waves to knock seals of the ice. One group even found out that turning a shark upside down immobilizes it and hence they hunt for sharks.

7)A common occurrence is to see killer whales "play"with their food. Although it seems cruel, this "playing"is often the way to pass on knowledge of hunting to the calves.

8)Apart from captivity, there has been only one documented attack of a killer whale on a human where the orca attacked the diver thinking he was a seal but let him go immediately.

9) Captivity is a major issue at the present moment. It is believed that orcas become neurotic, sociopathic and extremely aggressive when put in a limited space. Not only that but they contract diseases from mosquitoes, bird defecating in the pool and from infected injuries which are often self harm.

10)They can be found all across the globe, mostly around colder waters with a preference to coastal areas rather then the open ocean.