All About Orcas

There have been multiple news headlines surfacing recently which tell stories of orcas repeatedly ramming small boats along several European coastlines. This, alongside their commonly used title of ‘killer whale’, doesn’t paint a very positive image of these creatures but in reality, they are an incredibly intelligent species which scientists can’t seem to get enough of researching. Let’s take a leap into the fascinating lives of orcas!

There are believed to be just over 40 separate populations of orca which live in oceans around the world and whilst they prefer colder climates, they can be seen anywhere from the icy poles to the sweltering equator. Each pod consists of family groups which live and travel together for their lifetime and a pod can cover up to an incredible 160 kilometres per day. They recognise each other with clicks and whistles which are unique to each population and further use echolocation to help them navigate and hunt for food. When it comes to food, these animals will eat a wide range of other species from small herring to humpback whales, salmon to squid. A common hunting method when on the prowl for fish sees them work as a group to corral fish together into a tight ball encircled by hungry orcas. They then use their tails to stun the fish, in which state they can grab a bite more easily. Some populations have actually adapted to have different very specific diets. For example, those residing in the waters around New Zealand have acquired a taste for stingray and have been seen moving into shallow mangroves and harbours where they flip rays upside down. This actually puts some ray species into an immobile state which makes them much easier to eat. Patagonian orcas alternatively, dangerously beach themselves on the shore to snatch sea lion pups before wriggling their way back into the ocean. In fact, it is actually due to their feeding methods that they obtained their common name. Ancient sailors observed these creatures working in groups to kill whales much larger than themselves which led to them being nicknamed whale killers which eventually reversed to become killer whales. These creatures do form quite an ominous presence in the water at 10 metres long and weighing in at 10 tons. Their iconic tall dorsal fins can stretch up to 1.8 metres, making this an easy way to identify them at sea. Despite this great size however, killer whales are actually part of the dolphin family and not a whale as their name suggests.

There have been multiple studies carried out on orca populations over the last 50 years as scientists have discovered just how intriguing this species is and surprisingly, they have many similarities to us humans. The use of drones has been able to unlock new ways of accessing the lives of marine life and recent aerial footage has helped us understand their social arrangements. Orcas travel in family groups but it has been seen that females and younger individuals are more sociable than older orcas which tend to be pushed to the edge of the group. Individuals were also identified to favour some orcas over others, choosing to spend more time with those of the same gender and a similar age. Researchers used physical contact as one indicator of friendship whilst animals surfacing together and acting in unison were also taken as a sign of having a close bond.

Further studies have revealed that female orcas who give birth to a son are significantly less likely to give birth to another calf in the future. Whilst daughters learn to fend for themselves and hunt once they reach adulthood, males remain dependent on their mother for their whole lives, giving them the nickname ‘mummy’s boys’. Mothers have been documented catching salmon, taking a bite for themselves and then passing the other half on to the fully grown sons who depend on them for food. This drains a lot of the mother’s energy to the point where her reproductive abilities are compromised, making having a baby boy a lifelong sacrifice and a significant commitment. In fact, the likelihood of raising another calf to one year old after having a son is cut by around 50%. It also means that males tend to die shortly after their mothers have passed away. Scientists believe that this lifelong investment into a son could be the orcas hedging their bets as the biggest males will go on to father more children and therefore successfully pass on their genes.

Research has been conducted along similar lines into older females as aside from humans, orcas are one of only two mammal species which undergo menopause. Many scientists, doctors and authors have followed the studies in the area as a way to better understand menopause in humans too. In evolutionary terms, menopause goes against natural selection which dictates that any characteristic which reduces an animal’s chance of passing on their genes will be phased out due to survival of the fittest. Yet orcas are found to live long beyond their reproductive years, an anomaly in the animal kingdom. The average female will stop reproducing in her 30s or 40s but have an average life span of 90 years. So what do they do with all that time and how is it a survival advantage? Whilst scientists are not yet certain, there seems to be a range of plausible hypotheses. Older females, known as matriarchs, have often been seen leading at the front of pods in the search for food. This is especially true in years when food sources are low and it is believed they are using their greater ecological knowledge to lead the rest of the family to essential food sources. There is also the suggestion that menopause occurs so that mothers and daughters do not give birth to new calves at the same time. This would mean parental care and food sources would be stretched thinly, lowering survival chances of the calves.

Now it seems that researchers are trying to understand why these animals are suddenly attacking small vessels with increasing frequency. The worst affected area seems to be along the Spanish and Portuguese coasts where incidents have tripled in the last two years, up to 207 encounters in 2022. Many headlines have speculated that the orcas are taking revenge after possible previous ship strikes on members of their pod but some researchers believe these creatures are just having fun. They believe it likely started with a few youngsters becoming intrigued by the shape of a boat hull bobbing under the water and started playing with it like a toy. Orcas are very social learners and so this behaviour has now been passed on to others. It seems the idea that these attacks are revenge is unlikely as should an orca wish to truly damage a boat, they could do so easily, whilst there has never been a case of an orca harming a human in the wild. Most poignantly, if it was revenge, why would they wait until now when they have been targeted and mistreated by humans for decades?

Whilst orcas are one of many species targeted by whaling, they have also been under threat due to their popularity in sea parks. The population of orcas in the Salish Sea on the American Canadian border were particularly hard hit in the 1960s and 1970s. During this time, 13 orcas were killed during captures and 45 were taken to marine parks from a population of less than 100. Lolita may be the most famous of these as she was captured as a youngster and remains in a marine park today, over 50 years later. Her companion, Hugo, died in 1980 and she has not seen another member of her species since, leading many to claim her as ‘the loneliest whale in the world’. Earlier this year however, the sea park she is housed in announced that they hope to release her back into the wild, a plan thought to cost $20 million! Her siblings are still alive, as is her mother who is now believed to be 90. Lolita will initially be released into a secure ocean sanctuary where she will be taught how to hunt and also encouraged to swim which will strengthen her muscles. From there it is hoped she may be able to live a more free and natural life.

Whilst the risk of whaling and capture for human entertainment is falling, there are still several threats which place these magnificent animals at risk. Food shortages are a major issue, affecting some of their prey such as salmon and are caused by over fishing, habitat destruction and an increase in disease coming from commercially farmed fish. In addition to this, much of the food they do eat contains plastic or chemical pollutants which are now filling our oceans. With orcas being a top predator, it means they are consuming all the pollutants which have accumulated in prey species throughout the food chain which then lie in their fatty tissues in dangerously high levels, leading to multiple diseases and lower reproduction rates. Orcas are also affected by increasing shipping traffic which leads to potentially fatal ship strikes and noise pollution which impacts their ability to communicate effectively and hunt. We have so much more to learn from these incredibly intelligent animals with such complex and so far largely misunderstood habits that we must do all we can to protect them and the blue planet they live in.

By Neve McCracken-Heywood