The underlying mystery is their sharp senses. Animals have a hearing range better than the humans (20Hz to 20,000Hz). During a storm or earthquake, such animals and birds with these sharp senses ranging from very low frequency (infrasound) to high frequency sounds (ultrasound) will detect the foreshocks and go crazy. If humans could hear these low frequency sounds, we would act weird too. AFAIK this is the only plausible explanation that science can confirm yet.
