//
you're reading...

Behavior

The view from a sperm whale’s nose

Tønnesen P, Oliveira C, Johnson M, Madsen PT. The long-range echo scene of the sperm whale biosonar. Biol Lett. 2020;16: 20200134. https://royalsocietypublishing.org/doi/10.1098/rsbl.2020.0134

Seeing with sound

What happens if you place a microphone on the tip of a sperm whale’s nose? Putting anything on the nose of a 50-foot (15-meter) giant is no easy task, but the reward is a glimpse of how the world’s largest toothed predator sees the world.

A sperm whale’s tail flukes over the surface of the water as it dives. (Image source: Wayne Hoggard, NOAA)

Led by their gigantic noses, sperm whales hunt for food in the dark depths of the sea. Diving down to where sunlight doesn’t penetrate, these magnificent predators search for prey using the most powerful sounds produced by any animal. The loud clicks that sperm whales produce while diving are used for echolocation. Just like sonar used by naval ships or fishing vessels, animals that echolocate emit sounds and then listen for the echoes. The sounds they emit will bounce off objects around them and return to the animal along with important information about how far away the object is and what it’s made out of. Piecing together echo after echo, sperm whales create a collage of sound, painting a picture of the world around them click by click.

Toothed whales, including dolphins and sperm whales, use echolocation to detect prey. They emit pulses of sound and then listen for the echoes that return after bouncing off of an object ahead of them, such as a fish. (Figure source: Achat1999, Wikimedia Commons)

Until recently, no one knew for sure what exactly sperm whales “saw” using echolocation. The idea that sperm whales use their clicks for echolocation comes from observations of other toothed whales, like dolphins and porpoises, which emit similar clicks and buzzes.  Experiments with animals in captivity have revealed the echoes which can be used for navigation or hunting prey.

Studying the echoes received by a sperm whale is much harder than studying those received by smaller toothed whales. This is in part because sperm whales can’t be kept in captivity, but also because the size of their noses makes it very hard to record these echoes. Unlike the slender snout of a dolphin, sperm whale noses are almost rectangular and make up nearly a third of the whale’s massive body.

A mother sperm whale and her calf swim together just below the surface. (Image source: Gabriel Barathieu, Wikimedia Commons)

Tagging leviathan

Tags containing microphones have been deployed on the backs of sperm whales before, but their huge noses create shadows, effectively blocking out any returning echoes from being recorded on a tag. When the echoes arrive, the whale hears them through the front of its nose, which also stops the sounds from moving any further. Aiming to record sperm whale sonar on its return trip, researchers decided to try moving their microphone-containing tags. For the first time, sounds were recorded from the tip of a sperm whale’s nose.

The resulting sound recordings were pieced together to render what the researchers called the “echo scene” of a sperm whale, which was recently reported in an article in the journal Biology Letters.

From this echo scene, the research team was able to draw two conclusions. First, sperm whales can locate prey in the deep sea at long ranges. In one recording, echoes from deep sea creatures were detected from 144m (about 472 feet) away. Given that sperm whale hearing systems are likely even more sensitive than the microphones used in the study, sperm whales can probably detect prey at even further ranges.

Sperm whales are the largest toothed animals in the world. Here a human scuba diver is shown for scale along with the average size of a male and female sperm whale. (Figure source: Kurzon, Wikimedia Commons)

Second, contrary to previous theories, sperm whales do not use their loud clicks to debilitate prey. In the past, some scientists have wondered whether the incredibly powerful sounds produced by sperm whales could paralyze prey, rendering them immobile in the water and easy to catch and eat. But, based on the sound levels recorded from outgoing clicks and the average distances to prey, it appears that sperm whale clicks are not loud enough to stun fish or squid.

Innovative animal-borne tagging technology for tracking and recording behavior has provided important insight in studies across the animal kingdom. Combined with the ingenious and novel tag placement on the tip of a whale’s nose, this study gives us, for the first time, an idea of what a sperm whale sees on its deep hunting dives.

Discussion

No comments yet.

Post a Comment

Instagram

  • by oceanbites 2 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 3 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 4 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 5 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 7 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 8 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 8 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 9 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 9 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 10 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 11 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 11 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com