What is an orca?

ORCA (Orcinus orca) are also known as killer whales. However, they are the largest member of the dolphin family. They are mammals, and as such are warm blooded, air breathing, and bear their young alive.

Where do orcas live?

Orca are found in all the oceans of the world, though they are reported most often near the continental shelves. A number of records exist off Antarctica, Argentina, Iceland, Japan, Kamchatka (Russia), Norway, New Zealand, Papua New Guinea, Pacific Northwest (North America), and the United Kingdom. However, to date, no research project has identified large populations in any one area.

Do orcas have teeth?

Orca are one of the toothed whales (Odontoceti), as are other dolphins and porpoises, pilot whales and sperm whales etc. Orca have 10 to 13 pairs of interlocking conical teeth in the upper and lower jaws, usually with a total of 48. Just like a tree, you can count the number of rings within the teeth and these indicate how old an individual is.

What are the parts of an orca?

How big do orcas grow?

Male orca grow to a maximum length of approximately 9.8 m (32 ft) and a weight of 9 - 10,000 kg (10 - 11 tons). Female orca are smaller and grow to a maximum length of approximately 8.5m (28 ft) and a weight of 6,500 to 7,500 kg (7 -8 tons). Orca calves, at birth, are approximately 2.4 m (8 ft) long and weigh about 180 kg (400 lbs).

Orca are sexually dimorphic, which means they have a different body shape and size for the two sexes. These differences start to appear at around 10 - 15 years of age. One distinguishing feature is the dorsal fin, which in mature adult males may reach almost 2 m (6 ft), and is often triangular in shape. The dorsal fin on females typically only grows only to an average of 1 m (3 ft), and is curved in shape, more like that of a dolphins fin.

Are all orcas black and white?

Orca pigmentation is typically a distinctive black and white with a grey saddle patch (behind the fin), but some orca found around Antarctica are grey and white, with very pale saddle patches. All orca have a white eye patch (just above and behind the eye). The underside of the tail is typically white, however the complex underside marking of the genital area, which stretches up onto the sides of the tail, and the flanks of the orca, differ between the sexes.

How long do orcas live?

Orca may live as long at 80 years, but studies show that for one population living off Washington and B.C. coasts (USA and Canada, respectively) female orca live an average of 50 years. It is not clear why, but male orca from this population live shorter lives, on average only about 30 years, although they may reach a maximum age of 50 years.

At what age do orcas mature?

Female orca may start reproducing as early as 11 years of age. Young maturing orca females may become "babysitters" in preparation for the later responsibility of mothering. In her lifetime, a female may expect to have 4 to 6 offspring and will stop reproducing after about forty years of age, although there are exceptions to this. The gestation period is about 17 months.

On average males begin to mature around 12 - 14 years. This period is marked by rapid growth in the dorsal fin. As the dorsal fin grows it begins to straighten out and lose its earlier curve. This growth is often termed "sprouting". Growth of the dorsal fin and body continues until the orca is approximately twenty years of age.

Do orcas live in family groups?

Orca are very social animals. In some instances they live in small nuclear and extended families . We are not sure of the social structure of the groups of orca found off Peninsular Valdez as no genetic studies have been conducted to confirm field observations.

Are there multiple species of orcas?

Currently, it is considered that there is only one species of orca, however geographic isolation may have created different unique races and populations. For instance, some of the better known examples come from the Pacific Northwest, along the Washington, British Columbian and Alaskan coasts, where there are least two distinct types of orca. These are referred to as “Transients” and “Residents”.

These two types of orca share the same ocean but they don’t mix, and differ in their social habits, range, diet and to some extent even their physical appearance. Additionally, there is a third type of orca, termed the “Offshores”, who occasionally venture into this area. Again, they do not mix with the other orca.

Similar divisions of ‘types’ of orca have been found in other areas, such as Antarctica, where there is a “Type A”, “Type B” and “Type C”. Each is distinguishable based on their pigmentation. “Type A” look like typical black and white orca, but “Type B” and “Type C” orca are grey and white and “Type B” have big eye patches while “Type C” have small eye patches that are angled upwards. There is some evidence that these different types of orca may live in different habitats (e.g., close to the ice, or out in the open waters), and hunt on different prey e.g., penguins and seals, or fish.