Watch killer whales in the Salish Sea use tools to scratch each other’s backs. Video via Science News.
Killer whales make tools to scratch each other’s backs
For the first time, scientists have witnessed marine animals making and using tools. A team of scientists from the University of Exeter and the Center for Whale Research (CWR) said on June 23, 2025, that they took crystal-clear footage of killer whales using tools to scratch each other’s backs. They witnessed a population of killer whales select kelp stalks, cut them and use them to scratch the backs of their fellow whales.
The team published its study in the peer-reviewed journal Current Biology on June 23, 2025.
You scratch my back, I’ll scratch yours
The team of scientists observed three groups of southern resident killer whales that inhabit the Salish Sea. This sea separates the Olympic Peninsula in Washington state from Vancouver Island in Canada.
The study lasted 12 days. On eight of the 12 days, researchers observed the killer whales bite off the end of a kelp stalk, place it between themselves and their partner, and roll it between their bodies for several minutes.
Furthermore, killer whales of all ages engage in this practice, possibly to strengthen social bonds and, at the same time, promote skin health. Michael Weiss, director of research at CWR, said:
Males and females of all life stages and from all three southern resident pods were seen using kelp in this way. All evidence points to it being an important part of their social lives.
Kelping and allokelping
Apparently, whales also know how to enjoy life and a good day of spa-like seaweed treatments. Several species of whales are known to practice kelping. This is the term scientists use when whales rub their heads, flippers and bodies against seaweed, likely to remove dead skin and parasites and maintain healthy skin.
But the new discovery, called allokelping, involves the collaboration of another whale. It’s a significant find, as this strategy – in which one animal selects, cuts and manipulates seaweed to use with a companion who can’t properly scrub its own back – demonstrates the intelligence and sociability of killer whales. Weiss said:
We were amazed when we first noticed this behavior.
Watch a humpback whale performing the kelping behavior.
How do killer whales bond?
Social animals tend to use different strategies to socialize with other members of their group, other populations and even other species. Humpback whales, in particular, are a great example of intelligence and sociability. These whales protect calves, females and even other species from predators. They also possess excellent communication skills, using their flippers and calls, and producing underwater rings to communicate with each other and with other species, including humans.
But southern resident killer whales are somewhat more retiring, as they live in close, stable family groups. Therefore, they lack contact with other populations or species, but they remain sociable creatures within their group. In their case, they rely on touch to bond. Thus, killer whales approach other members of their group and touch each other’s bodies and fins to establish a closer relationship. Darren Croft, University of Exeter and Chief Executive of the CWR, said:
We know touch is really important. In primates – including humans – touch moderates stress and helps to build relationships.
Scientists also say these killer whales are more likely to pair with close maternal relatives and those of a similar age to practice allokelping.
But in addition to bonding, using seaweed might also be important for skin health. Other species of whales and dolphins rub against seaweed to remove dead skin and parasites. Brown algae, such as bull kelp, also have antibacterial and anti-inflammatory properties that may provide additional benefits to these animals.
How was the discovery made?
Although scientists have been studying this population of killer whales for about 50 years, they are still making interesting discoveries. Technology continues to improve, providing us with increasingly effective tools.
Therefore, scientists are conducting further research using cutting-edge technology to confirm these findings about the social and skin health benefits of this behavior. Rachel John, a master’s student in animal behavior at the University of Exeter, commented:
This population of whales has been formally studied for 50 years – the best-studied orcas on the planet – and yet major new discoveries can still be made.
This discovery is largely due to advances in technology. Drones used for whale observation now offer better image quality. John explained:
We hadn’t noticed ‘allokelping’ before because the videos being collected from our previous aircraft weren’t of high enough quality, but the footage we’re getting now shows this behavior in great detail.
I was watching one of those really close-up videos when I saw something that looked like a brown stick between two whales that were in contact with each other. We looked back at lots of videos and realized that rubbing kelp between their bodies wasn’t just a one-off thing. It was happening all the time. And once we saw whales breaking off pieces of kelp intentionally, it became clear that this is not just play – this is something important in the social lives of the southern resident killer whales.
Do all killer whales practice allokelping?
It appears this is a practice exclusive to southern resident killer whales. Other killer whale populations resort to other methods. For example, some rub their bodies on smooth pebble beaches, possibly to remove dead skin and parasites. However, southern resident killer whales have not been observed doing this.
There are also beaches in Canada where northern resident killer whales rub themselves on bull kelp. However, this kelp is dying due to rising water temperatures. Therefore, the Canadian government is protecting these beaches for northern killer whales. Similar protection may be needed for southern resident killer whales.
According to the latest CWR census, as of July 2024, only 73 southern resident killer whales remain. Since they do not interbreed with other killer whale populations, this number is alarmingly low.
In addition, not only does the change in water temperature and the resulting decline in algae blooms affect killer whales, but their primary food source is also declining.
Southern resident killer whales feed primarily on Chinook salmon, whose population has declined drastically due to factors such as overfishing, climate change and the destruction of spawning habitat. Adult salmon swim upriver to return to where they were born. This is where they reproduce and lay eggs. However, this ancient habit is being disrupted by the construction of dams.
What does the future hold for these animals?
When you add to an already timid population the factors of changing water temperatures, water pollution, lack of food and the noise of human activities, these creatures face a difficult future. Weiss said that unless major changes are implemented, the outlook for the southern resident killer whales is:
… very bleak. We’re not seeing the birth rate that’s required to sustain the population. Under the status quo, all of our projections indicate the population will continue to decline.
They are struggling to find enough of the large, fatty Chinook salmon that they need to survive and successfully rear their young.
The uniqueness of southern resident killer whales
Every killer whale population is unique. Allokelping is further evidence of the distinct personalities that southern resident killer whales possess. If we don’t care for them now, we will lose much more than 73 individual animals or one genetic lineage. We will lose a complex society and a deep and unique set of cultural traditions.
Croft said:
These new results highlight a potential additional threat to the future survival of the southern resident killer whales: the kelp forests where they select their grooming tools are in decline due to rising ocean temperatures associated with global warming. Protecting the future of these kelp forests, where the killer whales make their tools, may be important in preserving this unique culture and ensuring the southern resident killer whale population continues for generations to come.
Bottom line: Killer whales are sociable and intelligent animals that create tools to scratch a partner’s back. See the images here.
Source: Manufacture and use of allogrooming tools by wild killer whales
Salmon, coming home after a century, are our lifeform of the week
Humpback whales communicate with us using “smoke” rings
The post Killer whales make tools to scratch each other’s backs first appeared on EarthSky.
from EarthSky https://ift.tt/02qT5CK
Watch killer whales in the Salish Sea use tools to scratch each other’s backs. Video via Science News.
Killer whales make tools to scratch each other’s backs
For the first time, scientists have witnessed marine animals making and using tools. A team of scientists from the University of Exeter and the Center for Whale Research (CWR) said on June 23, 2025, that they took crystal-clear footage of killer whales using tools to scratch each other’s backs. They witnessed a population of killer whales select kelp stalks, cut them and use them to scratch the backs of their fellow whales.
The team published its study in the peer-reviewed journal Current Biology on June 23, 2025.
You scratch my back, I’ll scratch yours
The team of scientists observed three groups of southern resident killer whales that inhabit the Salish Sea. This sea separates the Olympic Peninsula in Washington state from Vancouver Island in Canada.
The study lasted 12 days. On eight of the 12 days, researchers observed the killer whales bite off the end of a kelp stalk, place it between themselves and their partner, and roll it between their bodies for several minutes.
Furthermore, killer whales of all ages engage in this practice, possibly to strengthen social bonds and, at the same time, promote skin health. Michael Weiss, director of research at CWR, said:
Males and females of all life stages and from all three southern resident pods were seen using kelp in this way. All evidence points to it being an important part of their social lives.
Kelping and allokelping
Apparently, whales also know how to enjoy life and a good day of spa-like seaweed treatments. Several species of whales are known to practice kelping. This is the term scientists use when whales rub their heads, flippers and bodies against seaweed, likely to remove dead skin and parasites and maintain healthy skin.
But the new discovery, called allokelping, involves the collaboration of another whale. It’s a significant find, as this strategy – in which one animal selects, cuts and manipulates seaweed to use with a companion who can’t properly scrub its own back – demonstrates the intelligence and sociability of killer whales. Weiss said:
We were amazed when we first noticed this behavior.
Watch a humpback whale performing the kelping behavior.
How do killer whales bond?
Social animals tend to use different strategies to socialize with other members of their group, other populations and even other species. Humpback whales, in particular, are a great example of intelligence and sociability. These whales protect calves, females and even other species from predators. They also possess excellent communication skills, using their flippers and calls, and producing underwater rings to communicate with each other and with other species, including humans.
But southern resident killer whales are somewhat more retiring, as they live in close, stable family groups. Therefore, they lack contact with other populations or species, but they remain sociable creatures within their group. In their case, they rely on touch to bond. Thus, killer whales approach other members of their group and touch each other’s bodies and fins to establish a closer relationship. Darren Croft, University of Exeter and Chief Executive of the CWR, said:
We know touch is really important. In primates – including humans – touch moderates stress and helps to build relationships.
Scientists also say these killer whales are more likely to pair with close maternal relatives and those of a similar age to practice allokelping.
But in addition to bonding, using seaweed might also be important for skin health. Other species of whales and dolphins rub against seaweed to remove dead skin and parasites. Brown algae, such as bull kelp, also have antibacterial and anti-inflammatory properties that may provide additional benefits to these animals.
How was the discovery made?
Although scientists have been studying this population of killer whales for about 50 years, they are still making interesting discoveries. Technology continues to improve, providing us with increasingly effective tools.
Therefore, scientists are conducting further research using cutting-edge technology to confirm these findings about the social and skin health benefits of this behavior. Rachel John, a master’s student in animal behavior at the University of Exeter, commented:
This population of whales has been formally studied for 50 years – the best-studied orcas on the planet – and yet major new discoveries can still be made.
This discovery is largely due to advances in technology. Drones used for whale observation now offer better image quality. John explained:
We hadn’t noticed ‘allokelping’ before because the videos being collected from our previous aircraft weren’t of high enough quality, but the footage we’re getting now shows this behavior in great detail.
I was watching one of those really close-up videos when I saw something that looked like a brown stick between two whales that were in contact with each other. We looked back at lots of videos and realized that rubbing kelp between their bodies wasn’t just a one-off thing. It was happening all the time. And once we saw whales breaking off pieces of kelp intentionally, it became clear that this is not just play – this is something important in the social lives of the southern resident killer whales.
Do all killer whales practice allokelping?
It appears this is a practice exclusive to southern resident killer whales. Other killer whale populations resort to other methods. For example, some rub their bodies on smooth pebble beaches, possibly to remove dead skin and parasites. However, southern resident killer whales have not been observed doing this.
There are also beaches in Canada where northern resident killer whales rub themselves on bull kelp. However, this kelp is dying due to rising water temperatures. Therefore, the Canadian government is protecting these beaches for northern killer whales. Similar protection may be needed for southern resident killer whales.
According to the latest CWR census, as of July 2024, only 73 southern resident killer whales remain. Since they do not interbreed with other killer whale populations, this number is alarmingly low.
In addition, not only does the change in water temperature and the resulting decline in algae blooms affect killer whales, but their primary food source is also declining.
Southern resident killer whales feed primarily on Chinook salmon, whose population has declined drastically due to factors such as overfishing, climate change and the destruction of spawning habitat. Adult salmon swim upriver to return to where they were born. This is where they reproduce and lay eggs. However, this ancient habit is being disrupted by the construction of dams.
What does the future hold for these animals?
When you add to an already timid population the factors of changing water temperatures, water pollution, lack of food and the noise of human activities, these creatures face a difficult future. Weiss said that unless major changes are implemented, the outlook for the southern resident killer whales is:
… very bleak. We’re not seeing the birth rate that’s required to sustain the population. Under the status quo, all of our projections indicate the population will continue to decline.
They are struggling to find enough of the large, fatty Chinook salmon that they need to survive and successfully rear their young.
The uniqueness of southern resident killer whales
Every killer whale population is unique. Allokelping is further evidence of the distinct personalities that southern resident killer whales possess. If we don’t care for them now, we will lose much more than 73 individual animals or one genetic lineage. We will lose a complex society and a deep and unique set of cultural traditions.
Croft said:
These new results highlight a potential additional threat to the future survival of the southern resident killer whales: the kelp forests where they select their grooming tools are in decline due to rising ocean temperatures associated with global warming. Protecting the future of these kelp forests, where the killer whales make their tools, may be important in preserving this unique culture and ensuring the southern resident killer whale population continues for generations to come.
Bottom line: Killer whales are sociable and intelligent animals that create tools to scratch a partner’s back. See the images here.
Source: Manufacture and use of allogrooming tools by wild killer whales
Salmon, coming home after a century, are our lifeform of the week
Humpback whales communicate with us using “smoke” rings
The post Killer whales make tools to scratch each other’s backs first appeared on EarthSky.
from EarthSky https://ift.tt/02qT5CK
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