Scientists have described three ìpopulationî categories of killer whales: Residents, Transients and Offshores. Residents hunt in large groups, eat fish (such as salmon), and have a total range of about 500 miles. Both the southern and northern communities are made of resident orcas. Transients and have an extremely broad diet, including fish, gulls, penguins, turtles, squid and marine mammals, even including large whales such as Greys, Humpbacks and Blue whales. They also travel in smaller groups and have a range of about 900 miles. Very little is known about offshores , except that they possibly eat schooling fish.

Another difference between residents and transients seems to be the way they ìtalkî to each other. It seems ìresidentsî will vocalize much more frequently and their vocalizations will be different from transients. Transients, on the other hand, tend to communicate only when socializing and especially after a successful kill. It is believed that this is a refined hunting technique on the part of transients since their prey on marine mammals which have very good hearing (as opposed to salmon). Another subtle difference seems to lie in their saddle coloration and dorsal fin shape.

Male orcas have the tallest dorsal fin known in the animal kingdom, measuring up to 6 feet (1.8 m) high in mature males; it can be as tall as a man. Females have shorter, more curved dorsal fins. Males also tend to be larger than females and grow to an average length of 30 feet (9.1 m) and can weigh over 8 tons. Females grow to about 23 feet (7 m) long and usually weigh over 4 tons. Killer whales begin reproducing in their mid-teens. Females have a gestation period of 17 months. They give birth to a single calf that is usually about 7 feet long, weighs 400 pounds (181 kg) and will nurse at least 1 year, maybe even up to 2. Killer whales will give birth at 3-8 year intervals (North Eastern population) having a total of 4-6 calves throughout their lifetime. The young stay with their mothers in the same pod for the rest of their life. On average, females live 50 years and have been known to live up to 80 or 90 years. Males have a much higher mortality rate and usually live 30 years with a maximum lifespan of 50 to 60 years.

The collapsed dorsal fins commonly seen in captive killer whales do not result from a pathogenic (from disease) condition, but are instead thought to most likely originate from an irreversible structural change in the fin's collagen over time. Possible explanations for this include alterations in water balance caused by the stresses of captivity or dietary changes, lowered blood pressure due to reduced activity patterns, or overheating of the collagen brought on by greater exposure of the fin to the ambient air. Collapsed or collapsing dorsal fins are rare in most wild populations.

As it stands, all known killer whale populations are, at some level, threatened. There are questions regarding the long-term survival of this most fascinating predator. Some studies even calculate the complete extinction of a specific population in 33 to 120 years at its going rate of decline.

- Southern Resident Population ñ Endangered
- Northern Resident Population ñ Threatened
- Transient Population ñ Threatened
- Pacific Offshore Population - Special Concern

The only ìpredatorî to ever come close to equaling man is slowly going down in a blaze of glory. Should this species disappear, we will find ourselves in great jeopardy because our oceans will lose any chance they ever had at keeping some sort of natural balance. There still is timeÖ.let's not waste it.