Killer whales use seaweed as tools to groom each other
Using drones to observe a population of killer whales in the Salish Sea, part of the Pacific Ocean between Washington state and British Columbia, researchers noticed that these predators engaged in a behavior they named "allokelping," one of the few known examples of tool use by marine mammals.
The killer whales find large stalks of a type of seaweed called bull kelp, either attached to the seabed or floating at the surface. They then bite off the end of the stalk, position it between themselves and another killer whale and roll the kelp between their bodies.
The researchers hypothesize that the behavior promotes skin health while strengthening social bonds. Other populations of killer whales have been observed rubbing their bodies on smooth stone beaches, possibly to remove dead skin.
"Most examples of tool use in animals involve solving ecological problems, such as gaining access to food. For example, chimpanzees use sticks to fish for termites. What's remarkable about this discovery is that the tool - the kelp - is used not to obtain food but to facilitate social interaction," said marine biologist Darren Croft of the University of Exeter in England, co-author of the study published this week in the journal Current Biology.
"This kind of socially motivated tool use is extremely rare in non-human animals and has previously only been observed in a small number of primates, usually in captivity," added Croft, executive director of the Center for Whale Research, a scientific organization based in Washington state that has studied this population of killer whales since the 1970s.
The researchers documented the behavior among both male and female killer whales of all ages. It likely plays an important role in their social lives, Croft said.
There are some other examples of tool use among marine mammals. Sea otters use rocks and other hard objects to crack open shells to get at the meat inside. And certain dolphins use marine sponges to protect their snouts and stir up the seabed while foraging. The researchers said the behavior by the killer whales goes one step further because they modify an object for use as a tool.
"While this is not the first documented case of cetacean or marine mammal tool use, it is - as far as we know - the first case of cetacean tool manufacturing with tool use. The whales are not just finding perfect lengths of kelp in the environment, but rather actively modifying larger intact stalks of kelp to create the pieces they are using for allokelping," said study co-author Rachel John, a University of Exeter graduate student studying killer whale behavior.
"Another key part of what makes this behavior so unique is the fact that they are manipulating the kelp cooperatively with a partner without the use of hands or any hand-like appendages. They use their mouth to position the kelp initially, but after that they only use the momentum and pressure of the core of their bodies to maintain contact with each other and the kelp between them," John added.
The behavior is known only among this killer whale population.
"We found that individuals with more visible peeling skin were more likely to engage in allokelping, suggesting that the behavior may serve a skin-care function. Brown seaweeds like kelp are known to have antibacterial properties, so it's plausible that rubbing with kelp helps improve skin health," Croft said.
"Second, we think this behavior likely plays a role in maintaining social bonds. Physical contact is known to be important for social cohesion in many species, including humans. Just as we might hug a friend we haven't seen in a while, it's possible that allokelping serves to reinforce social relationships among whales," Croft added.
This kelp grows in cold and nutrient-rich coastal and intertidal waters and thrives off the western coast of North America, which includes the home range of these killer whales.
This population is at grave risk of extinction, Croft said, with only 73 individuals counted in the latest census. They are highly specialized salmon hunters, particularly reliant on Chinook salmon. As salmon populations have declined, in part due to dam-building on spawning rivers, the whales have struggled to find enough food.
"In short, they are starving," Croft said.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
CNA
6 days ago
- CNA
For first time, Webb telescope discovers an alien planet
WASHINGTON :In addition to providing a trove of information about the early universe, the James Webb Space Telescope since its 2021 launch has obtained valuable data on various already-known planets beyond our solar system, called exoplanets. Now, for the first time, Webb has discovered an exoplanet not previously known. Webb has directly imaged a young gas giant planet roughly the size of Saturn, our solar system's second-largest planet, orbiting a star smaller than the sun located about 110 light-years from Earth in the constellation Antlia, researchers said. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). Most of the roughly 5,900 exoplanets discovered since the 1990s have been detected using indirect methods, such as through observation of the slight dimming of a star's light when a planet passes in front of it, called the transit method. Less than 2 per cent of them have been directly imaged, as Webb did with the newly identified planet. While this planet is large when considered in the context of our solar system, it is actually the least massive one ever discovered through direct imaging - 10 times less massive than the previous record holder. This speaks to the sensitivity of Webb's instruments. This discovery was achieved using a French-produced coronagraph, a device that blocks out the bright light from a star, installed on Webb's Mid-Infrared Instrument, or MIRI. "Webb opens a new window - in terms of mass and the distance of a planet to the star - of exoplanets that had not been accessible to observations so far. This is important to explore the diversity of exoplanetary systems and understand how they form and evolve," said astronomer Anne-Marie Lagrange of the French research agency CNRS and LIRA/Observatoire de Paris, lead author of the study published on Wednesday in the journal Nature. The planet orbits its host star, called TWA 7, at a distance about 52 times greater than Earth's orbital distance from the sun. To put that in perspective, our solar system's outermost planet Neptune orbits about 30 times further from the sun than Earth. The transit method of discovering exoplanets is particularly useful for spotting those orbiting close to their host star rather than much further out like the newly identified one. "Indirect methods provide incredible information for planets close to their stars. Imaging is needed to robustly detect and characterize planets further away, typically 10 times the Earth- to-sun distance," Lagrange said. The birth of a planetary system begins with a large cloud of gas and dust - called a molecular cloud - that collapses under its own gravity to form a central star. Leftover material spinning around the star in what is called a protoplanetary disk forms planets. The star and the planet in this research are practically newborns - about 6 million years old, compared to the age of the sun and our solar system of roughly 4.5 billion years. Because of the angle at which this planetary system is being observed - essentially looking at it from above rather than from the side - the researchers were able to discern the structure of the remaining disk. It has two broad concentric ring-like structures made up of rocky and dusty material and one narrow ring in which the planet is sitting. The researchers do not yet know the composition of the planet's atmosphere, though future Webb observations may provide an answer. They also are not certain whether the planet, being as young as it is, is still gaining mass by accumulating additional material surrounding it. While this planet is the smallest ever directly imaged, it is still much more massive than rocky planets like Earth that might be good candidates in the search for life beyond our solar system. Even with its tremendous capabilities of observing the cosmos in near-infrared and mid-infrared wavelengths, Webb is still not able to directly image Earth-sized exoplanets. "Looking forward, I do hope the projects of direct imaging of Earth-like planets and searches for possible signs of life will become a reality," Lagrange said.
CNA
24-06-2025
- CNA
Killer whales use seaweed as tools to groom each other
Killer whales are known for exceptional intelligence, displaying complex social structures and sophisticated communication. New research provides fresh evidence for this, documenting how these marine mammals use stalks of seaweed as tools to groom each other - as in, "You scratch my back and I'll scratch yours." Using drones to observe a population of killer whales in the Salish Sea, part of the Pacific Ocean between Washington state and British Columbia, researchers noticed that these predators engaged in a behavior they named "allokelping," one of the few known examples of tool use by marine mammals. The killer whales find large stalks of a type of seaweed called bull kelp, either attached to the seabed or floating at the surface. They then bite off the end of the stalk, position it between themselves and another killer whale and roll the kelp between their bodies. The researchers hypothesize that the behavior promotes skin health while strengthening social bonds. Other populations of killer whales have been observed rubbing their bodies on smooth stone beaches, possibly to remove dead skin. "Most examples of tool use in animals involve solving ecological problems, such as gaining access to food. For example, chimpanzees use sticks to fish for termites. What's remarkable about this discovery is that the tool - the kelp - is used not to obtain food but to facilitate social interaction," said marine biologist Darren Croft of the University of Exeter in England, co-author of the study published this week in the journal Current Biology. "This kind of socially motivated tool use is extremely rare in non-human animals and has previously only been observed in a small number of primates, usually in captivity," added Croft, executive director of the Center for Whale Research, a scientific organization based in Washington state that has studied this population of killer whales since the 1970s. The researchers documented the behavior among both male and female killer whales of all ages. It likely plays an important role in their social lives, Croft said. There are some other examples of tool use among marine mammals. Sea otters use rocks and other hard objects to crack open shells to get at the meat inside. And certain dolphins use marine sponges to protect their snouts and stir up the seabed while foraging. The researchers said the behavior by the killer whales goes one step further because they modify an object for use as a tool. "While this is not the first documented case of cetacean or marine mammal tool use, it is - as far as we know - the first case of cetacean tool manufacturing with tool use. The whales are not just finding perfect lengths of kelp in the environment, but rather actively modifying larger intact stalks of kelp to create the pieces they are using for allokelping," said study co-author Rachel John, a University of Exeter graduate student studying killer whale behavior. "Another key part of what makes this behavior so unique is the fact that they are manipulating the kelp cooperatively with a partner without the use of hands or any hand-like appendages. They use their mouth to position the kelp initially, but after that they only use the momentum and pressure of the core of their bodies to maintain contact with each other and the kelp between them," John added. The behavior is known only among this killer whale population. "We found that individuals with more visible peeling skin were more likely to engage in allokelping, suggesting that the behavior may serve a skin-care function. Brown seaweeds like kelp are known to have antibacterial properties, so it's plausible that rubbing with kelp helps improve skin health," Croft said. "Second, we think this behavior likely plays a role in maintaining social bonds. Physical contact is known to be important for social cohesion in many species, including humans. Just as we might hug a friend we haven't seen in a while, it's possible that allokelping serves to reinforce social relationships among whales," Croft added. This kelp grows in cold and nutrient-rich coastal and intertidal waters and thrives off the western coast of North America, which includes the home range of these killer whales. This population is at grave risk of extinction, Croft said, with only 73 individuals counted in the latest census. They are highly specialized salmon hunters, particularly reliant on Chinook salmon. As salmon populations have declined, in part due to dam-building on spawning rivers, the whales have struggled to find enough food. "In short, they are starving," Croft said.
CNA
12-06-2025
- CNA
FAA says probe closed into SpaceX Starship Flight 8
WASHINGTON :The Federal Aviation Administration said on Thursday it closed an agency-required investigation into a SpaceX Starship Flight 8 mishap, citing the probable cause as a hardware failure in one of the engines. SpaceX identified eight corrective actions to prevent a re-occurrence and the FAA said it verified SpaceX implemented those prior to the Starship Flight 9 mission in late May.
