When for example turtles are migrating and they say “60 thousand turtles coming” how do they know how many are there?

Question

When for example turtles are migrating and they say “60 thousand turtles coming” how do they know how many are there?

In: Biology

Answer 1

You look how much space the turtles take up, then you count the turtles in, say 1 square meter, and multiply that