Monarch butterflies really are beautiful
in many ways. One ability which is helpful in their travels
is to use the earth's magnetic field
. This comes in handy on cloudy
days and their schedule
still calls for some serious mileage north
. For all practical purposes they have a little compass
built in somewhere in their bodies.
Ref: J.A. Etheredge et al (1999) "Monarch butterflies ( Danaus plexippus L.) use a magnetic compass for navigation" Proceedings of the National Academy of Sciences, vol 96, no 24, pp 13845-6.