so how does it discern when its a mouse or a squirrel?

Mmmm PETA would love it... So much energy and creativity wasted on killing a mouse; the poor little things... for $7 you can buy one better, cheaper and more human.

There is actually a better mousetrap, which has been around for some time. Depending on how you operate it, it costs between nothing and what you are prepared to spend on it.
Its called a domestic cat. The farm I lived next to during my youth had a bunch of cats living off of the mice in the haystack and the care for my cats adds up over the years.
The drawback is that cats do not kill mice humanely, that you will find dead mice in odd places and if you do not let your cat go out you will need to keep and clean a litterbox. Unless you toilet-train your cat (no joke, look it up by googling).
The plus point is that cats are great fun to have around.

I wonder if they took into consideration the odor factor. Surely an electrocuted mouse is going to give off odors that mice could smell long before humans. Then again, perhaps they are not as wary as other wild animals can be. Pretty neat and tricky but I think a tad bit too expensive.

...mice, their time on earth is limited...

would it kill freakin rats also? rats are bigger than mice. i.e. way bigger.

Contrary to popular belief rats and mice do not commonly spread disease.

Ha, a kid inventors show in NZ had this mouse trap with plates as well! Except it was a tube and the \"bait\" was a female rat! All the boys were keen to get their wiggle on and got wasted.

I designed a better one. You put the cheese in place and when the mouse steps on the trigger, a 300 lb anvil falls on the mouse and squashes it flat in 1/10th of a second!!
It looks ok, except their description is tasteless. It sounds like the \"electric chair\" for the mouse, which it is.... but not very good advertising. It\'s probably more humane than other methods, yet they make it sound less human....

\"would it kill freakin rats also? rats are bigger than mice. i.e. way bigger.\"
For this you need the Victor 2000, KillaMouse Plus Series...