PTF.S1.Q1 - Sea turtles hatchlings leaving their hatching grounds...

ThereHUGO 170

I got it right due to process of elimination but Why are sea turtles able to sense the magnetic field?

sprsplspig

Hi! Here is my understanding:

Translation:
1. newly hatched sea turtles swim to the north, according to the earth's magnetic field.
2. in an indoor tank, we see the same thing happen (newly hatched turtle swim to the north)
3. but when we surround the tank with a fake magnetic field stronger than the earth's and in the opposite direction(assuming it would cover up the earth's magnetic field), the turtles swim in the opposite direction as well

So what can we most strongly infer from the above premises?
It's reasonable to think that the turtles ended up swimming in the opposite direction in prem.3 because they based their direction on the artificial magnetic field (which is opposite to earth's). So the turtles must be able to sense magnetic fields, and they don't just swim in whichever direction because of some crazy intuition or smell. If this is true, then without the artificial magnetic field, it must be the case that the turtles base their sense of direction on Earth's natural magnetic field, causing them to swim north.