CATS.

Cats have been associated with humans for at least 9,500 years and are currently the most popular pet in the world. Due to their close association with humans, cats are now found almost everywhere on Earth. Until recently the cat was commonly believed to have been domesticated in ancient egypt, where it was a cult animal. A study in 2007 found that the lines of descent of all house cats probably run through as few as five self domesticating african wildcats 8000 BC, in the near east. The earliest evidence of cat domestication is a kitten that was buried with its owner 9,500 years ago in Cyprus. Cats can function at only one-sixth the light level required for human vision. Cats have excellent hearing and can detect an extremely broad range of frequencies. They can hear higher-pitched sounds than either dogs or humans, detecting frequencies from 55 Hz up to 79 kHz, a range of 10.5 octaves; while humans can only hear from 31 Hz up to 18 kHz, and dogs hear from 67 Hz to 44 kHz, which are both ranges of about 9 octaves. Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually 12–16 hours, with 13–14 being the average. Some cats can sleep as much as 20 hours in a 24-hour period. The term Cat Nap refers to the cat's ability to fall asleep (lightly) for a brief period and has entered the English lexicon—someone who nods off for a few minutes is said to be "taking a cat nap". Cats are known for their cleanliness, spending many hours licking their coats.The cat's tounge has backwards-facing spines about 500 micrometers long, which are called papillae These spines allow cats to groom themselves by licking their fur, with the rows of papillae acting like a hairbrush. Some cats, particularly longhaired cats, occasionally regurgitate hairballs of fur that have collected in their stomachs from grooming. These clumps of fur are usually sausage-shaped and about two to three centimeters long. haha.