The recent earthquake has caused me to wonder about it. Dogs (and cats, too, I assume, as well as other animals) seem to sense earthquakes before we do. How? Why? Is it because of their inner ear structure being more sensitive?
Here’s a good page that talks about animal sensitivity to quakes. http://www.levity.com/mavericks/quake.htm
The short answer is, there is no definitive answer. Things have been observed but never proven.
Some theorise (sorry no cite) that animals and birds, having more sensitive hearing than us, can hear some kind of sound which alerts them in the hours before a quake.
Or my favorite theory - the animals aren’t more sensitive to the subtle cues, they just pay more attention to their environment.
Humans are busy watching TV, reading books, playing video games, yakking at each other - most critters are watching the landscape looking for predators. Who do you think will notice subtle vibrations and strange happenings sooner?
It is interesting…the last two minor tremblers we’ve had here were early in the morning and I was brought awake by the dog howling and the cattle loudly mooing, at least an hour before the earthquake.
Solar eclipses are interesting too. The birds seem particularly noisy prior to its occurrence and noticeably silent as it develops. The chickens look mighty confused as they head back to the roost.
Probably a little bit of both more sensitivity and more attention. Humans are used to a lot of vibration, due to the technology we have around. There is a constant low-level hum in my room (computers), and I have seen several cars drive by with their speakers up so loud they set off car alarms with the vibration. I live in Georgia, and the night before last we had a small earthquake. I pretty much slept through it, blowing it off as someone driving a lawnmower under my window (I am on the 2nd story).
Interestingly, it might be that the type of sense we use the most is adapted to in more ways than just sensitivity. I don’t respond to sound and vibration as a deer would, because I don’t use those skills as much. However, I use my sight more than a deer, and so I sleep with my eyes open. Changes in ambient light will wake me while a noise might not.