How do small animals know migration paths the moment they are born? Like how eels travel thousands of miles after they are born.

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How do small animals know migration paths the moment they are born? Like how eels travel thousands of miles after they are born.

In: Biology

Don’t they just travel in flocks with adults ? Isn’t it just passed on like that ?

There’s two ways to go about this.

The crude version is just an instinctive timer that compels the animal to migrate a certain direction. They don’t know where they’re going or what they’ll find when they get there, and there’s no specific destination in mind. This is typical for insect migrations – Monarch butterflies and locusts head south for the winter but don’t follow any specific routes or destinations. A butterfly won’t return to the same tree that its grandparents did – and it may even take multiple generations to complete the full circle.

Then there’s the more complex version you see in smarter, longer lived, and more social animals. Geese are also compelled to migrate south for the winter, but they have an *exact* route in mind that they’ve learned from their first journey. They will return to the exact same location year after year, following a path of landmarks that they pass down to their offspring.

It’s still hypothetical, but there is some evidence to suggest many animals can sense and possibly even see magnetic fields, which might be what migration paths are based on.

https://en.m.wikipedia.org/wiki/Magnetoreception

>Magnetoreception has been reported in the European eel,[33] while amphibians and reptiles including salamanders, toads and turtles exhibit alignment behaviours with respect to the Earth’s magnetic field.