Harbour seals have a secret weapon when it comes to navigating murky waters.  It is optic flow.  This is a fancy term for the way objects move across an animal's field of vision as it moves.  It is a big deal for these marine mammals.  Most people think that marine mammals have poor vision, especially in dark or cloudy water.  But harbour seals have shown that they can use optic flow to figure out their direction, even when the water is not clear.

Scientists wanted to see if harbour seals could use optic flow on the water's surface as well.  They created three different optic flow environments.  Three harbour seals were trained to figure out their heading in these environments.  The seals did amazingly well.  They had a mean accuracy of about 4. 61 degrees for volume optic flow.  This is when they are moving through a cloudy area.  For surface optic flow, which mimics moving over a surface, they had an accuracy of about 4. 96 degrees.  When moving underneath a surface, their accuracy was about 3. 58 degrees.  These results show that harbour seals can use optic flow information whenever there is enough light.  This goes against the idea that marine mammals have poor visual guidance.

So, what does this all mean?  It means that harbour seals have a pretty impressive ability to use visual information to navigate their environment.  This is true even in challenging conditions.  It also means that we have a lot more to learn about how marine mammals use their senses.  A closer look at how these animals perceive optic flow can help us understand more about vision in general.  It is not just about seeing.  It is about how animals use what they see to move and survive in their world.

Harbour seals are not the only marine mammals with impressive visual abilities.  Many other species have adapted to their aquatic environments in unique ways.  For example, some whales and dolphins have excellent low-light vision.  This helps them hunt in deep waters.  Other marine mammals, like sea otters, have adapted to their environments in different ways.  They use their whiskers to sense their surroundings.  This shows that marine mammals have a range of sensory adaptations.  These adaptations help them thrive in their underwater homes.

It is important to remember that harbour seals are just one example of how marine mammals use their senses.  There is still so much to learn about these amazing creatures.  Every new discovery brings us one step closer to understanding the complex ways that marine mammals interact with their environment.  It is a reminder that there is always more to learn and discover in the natural world.

HARBOUR SEAL BEHAVIOUR

Harbour Seals: Masters of Underwater Vision

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