However even 18 hours is not considered abnormal for a Chihuahua. This includes naps.There are 2 types of sleeping. One is a lighter sleep (called slow wave) and the other is the deeper sleep (known as REM-Rapid Eye Movement). Dogs, just like humans do have these 2 different types of sleep.
Probably the best known snake in the world, the Rattlesnake is a pit viper found almost everywhere in the United States, and is capable of a deadly bite. Its trademark rattle strikes fear into anyone who hears it.
Rattlesnakes, copperheads and cottonmouths are all pit vipers. Pit vipers are snakes with two pits under their nostrils to detect heat, thus enabling them to hunt warm-blooded prey. The pits are so sensitive that the snake can determine the size of the warm-blooded animal and can even detect prey in complete darkness.