Posted on by Ian O'Neill

Seals Use Astronomy as Navigation Aid

Yes, we’ve heard bees use the Earth’s magnetic field to navigate by. We’ve also heard about some bird species following the Sun to find the location of their evening roost. But what do we know about the animals living at sea? Do they use astronomical aids to help them find their way around the planet? Mammals such as whales are known to exhibit “skyhopping” behaviour when they surface from the water to have a look around, but seals go one step further; they can recognise and orientate themselves with the stars…

It was one of the first methods us humans used for navigation when sailing across the middle of a featureless ocean, we’d pick out known stars and constellations and relate them to our location on the planet’s surface. Explorers used astronomy to guide them to new lands, captains used the stars to direct their battleships toward the enemy and trade routes were repeatedly used thanks to star navigation. In its most basic form, star navigation could be carried out by linking stars with the location on the horizon when they rise, as was traditionally done by Polynesian sailors to colonize vast numbers of islands in the Pacific.

In a revealing study, researchers at the University of Southern Denmark in Odense have discovered that seals have the ability to recognise stars and groups of stars inside a modified planetarium. A five-metre round pool plus two harbour seals were covered with a dome with 6000 point light sources to simulate the Northern Hemisphere’s starry sky. Björn Mauck and his team found that if they selected an individual star with a laser pointer, they could train the seals to swim toward that star and then rewarded them with a treat if they did it correctly. Then the researchers would randomly orientate the dome, and without the help of a laser pointer, the seals would continue to swim toward the correct star.

“Seals and many other animals are exposed to the starry sky every clear night, and thus certainly have sufficient opportunities to learn the patterns of stars.” – Björn Mauck

This study strongly suggests that these two harbour seals have an amazing, natural ability to recognise the distribution of stars on a clear night.

So when you next see a seal popping to the ocean surface, it might not be simply checking out its surroundings, it might be trying to look for Sirius in the constellation of Canis Major…

Paper abstract: “Harbour seals (Phoca vitulina) can steer by the stars“, Mauck et al., 2008
Source: New Scientist

14 Replies to “Seals Use Astronomy as Navigation Aid”

  1. Hmmm…. I have heard turtles from a specific Japanese island swim all the way to Baja California to lay their eggs (takes them years, I think).. Then the hatchlings ( apparently without mom’s help) swim all the way ‘back’ to the same island…. To mate and start the process all over again. Or something like that.. Difficult for me to believe that they (or the seals) map the stars, but who knows? I think we will need more data. And hope we get it… I’m curious.

  3. Well.. To tell the truth, I think the turtles are probably following an ‘instinctive’ scent left by their ancestors (mom).. But have no clue about this “seal” thing..

  4. It’s wonderful and sad that they can follow the stars… given that so many of them are killed by human fools who club them to death as babies, for their fur.

  5. Hi Kevin,

    I see your point. When I was writing the article I was wondering whether it was simply a case of “training”, rather than instinct. But the fact that these seals can pick out a particular star from 6000 randomly orientated stars strongly suggests they have a natural ability to distinguish between stars. Whether they use this tool in nature will take some work, but it is interesting all the same.

    There are many subtleties in nature, its great we have scientists gradually unlocking these secrets…

    Cheers, Ian 🙂

  6. It is a LONG LEAP from showing a seal can be trained to follow a point-light source to “seals navigate using stars.”

  7. What a bunch of dung….

    Okay, so they trained some seals to follow stars they pointed at, is that the same as playing games with chimps and teaching dolphins to plant explosives. Just because they follow along does not mean they actually do this in the wild. Besides, would they really understand the precession of the stars and know what season they were in and follow the correct starts??? Maybe, but i doubt they have an inate star chart built into their head.

    Like religion…if you fail to think critically about something it will never cease to amaze you…..

    As far as turtles following scent markers accross an entire ocean…..Ummmm…maybe you should rethink that one. How do you leave a scent trail in the ocean?

  8. Kevin,
    True, it is good to think critically. It is also good to open a book once in a while and do research.

    Many animals smell in water. Smell is not limited to the medium of gas. It is well known sharks can ‘smell’ blood for instance. Some fish cannot see, but can smell their way to prey.

    You don’t need to understand how the universe works to follow stars. Just picking one consistently over and over amongst other stars is something some humans can’t seem to figure out.

  9. I think Kevin is on the right track with this story. Fully fleshed out, skeptical reasoning of this story reveals some confusing & controversial aspects of this study. Obviously more research & careful study is needed to add any validity to this subject. Great story nonetheless.

  10. So, from this study, we can conclude that seals can follow a laser pointer for a treat. This is news?

  11. Hi anthony,

    In my view this is news, fascinating news at that. I just wrote an article about a “rare asteroid” and I must admit, the seal story was of more interest to me. I suppose it depends on your point of view 🙂

    Besides, I love seals 😉

    Ian

  12. (1) Hmmm, how can we use star navigating seals in pristine Alaska to our military advantage!?

    (2) How can we use the asteroid impacted “dead zone” Gulf of Mexico to our oil drilling advantage?

    I’m no economist or politician, but I think congress should play the cards they are dealt correctly and not try to clean up the Dead Zone GOM (drill for oil there) and they should not risk polluting the pristine Alaska (don’t drill there).

    A wise guy once said, “wherever there is oil, there is more oil” …. no need to drill somewhere else is there!?

Comments are closed.