A glimpse into the lives of orca whales
Orcas, or killer whales, are the largest of the dolphin family and are the apex predator of the ocean. This means orcas are at the top of the food chain and nothing is preying upon them. Orcas are the most widely distributed of all marine mammals and can be found in all the world’s oceans. Orcas are able to travel more than 100 miles in a day, dive to 900-feet deep and can stay underwater for upwards of 15 minutes.
Orcas are believed to be one of world’s most intelligent creatures with brains that weigh 16-20 pounds. Not only are orcas very intelligent, they are also highly social and form complex bonds with other orcas and their family members. Orcas travel in pods, which are social groupings typically made of up family members, which range in size from 1-40 plus individuals.
Orcas communicate using clicks and whistles and are thought to possess language. Different populations of orcas have different sounding calls that can be distinguished by ear. Through studies with bottlenose dolphins, it has even been found that dolphins have specific names for each other.
Orcas have conical teeth and will swallow pieces of food that has been torn apart whole. Orcas are often also seen “prey-sharing” especially with younger individuals in the group. Orcas can eat up to 400 pounds of food per day! As fish eaters, resident orcas hunt using echolocation, which works like sonar, and is produced in the melon, the fatty area on an orca’s head, as a series of “clicks” that are then received as vibrations back through the bottom jaw. Echolocation brings a clear picture back to the orca of its surroundings. Orcas can pick a specific salmon from 300 feet away.
The distinct black and white coloration of the orca is easily identifiable. With black back sides, white bellies and white/gray markings, the orca is a beautiful marine mammal. Each individual orca can be identified by looking at the saddle-patch, a white/gray marking located behind the dorsal fin, as well as nicks, scars and other individual features (dorsal fin shape, fluke shape, etc.). The saddle-patch acts much like a fingerprint and is different for each individual orca.
Male orcas develop a large dorsal fin during their teen years that is easily spotted. The dorsal fin is entirely made of cartilage and can grow to heights of 6 feet in males. Female dorsal fins are shorter at around 2 feet.
Male orcas can reach lengths of a little over 30 feet and can weight up to 10 tons, while female orcas are typically smaller at about 25 feet and 8 tons.
Orca life history
Orcas have an amazing life history that is very similar to humans’. Females typically live 60-80 years but it is not uncommon for a female to live 90+ years, with the oldest known whale estimated to be 104 years old. Males have shorter life spans of 40-60 years.
Females typically reach sexual maturity in their early teens and will give birth every 2-5 years to a single calf. The gestation period for orca calves is 17 months, and calves are usually born at about 6-8 feet in length and 300-400 pounds. Calves nurse for about a year on their mothers 40% milk-fat milk. There is no specific calving season and births are recorded throughout the year. Orcas are one of the few animals that experience and live after menopause. Female orcas typically have their last calf by the time they are age 40 and can live 60 years past this time.
Orcas of Washington
Over the entire world’s oceans there are 10 recognized ecotypes of orcas and possibly even more. An ecotype is a genetically and culturally distinct variety of a population adapted to the specific environment. Adaptations reflect differences in prey, habitat and social networks. All of the orca ecotypes look very similar with small physical differences. The coloration, eye patch, dorsal fin and size of the animals all vary slightly between ecotypes. Here is Washington state, we have 3 of the known ecotypes of orcas: resident, transient and offshore.
Resident orcas are the most studied of the ecotypes as they tend to have smaller home ranges and more predictable travel patterns. Resident orcas are fish eaters and travel in large matriarchal family groups lead by the mother orca and made up of her offspring along with any cousins, aunts and uncles. These family groups can be quite large and consist of 40 or more individuals. There are several types of resident orcas across the world, but here in the Salish Sea we see the Southern Resident Killer Whales (SRKW). The SRKWs eat salmon and are usually seen in the inland sea during the summer months.
Transient orcas are marine mammals eaters and are just what their name suggests – transient. These animals are often seen one month in Alaska and the next here in the San Juans. Transient Orcas travel in small groups that often consist of moms and offspring, siblings and non-relative orcas traveling together. Transients typically travel in groups of 1-5 individuals, but sometimes will form larger groups of 10+ orcas. Transient orcas are excellent hunters and will eat seals, sea lions, porpoise, large whales such as grey whales and humpback whales, and have even been known to snack on birds! Transient orcas are spotted in the San Juans throughout the year but tend to be more elusive.
Offshore orcas are typically found 15+ miles off shore, but sometime will travel into the Salish Sea. Not much is known about this ecotype, but it is believed that they feed on sharks and large schooling fish.