So that they can jerk themselves back into the hole in the event of danger. An earthworm's rear end has little spikes on it that give it a grip on the sides of the tunnel.
Setae
The tail of an earthworm is made of the same stuff as the rest of its body. When an earthworms tail comes of, the head can grow a new one.
No, earthworms are very beneficial in a garden. Keep them in your garden!
They are natures little rototillers, and eat decayed matter.They like damp, loamy soil best .
under it to keep water out
Cats like to play with wiggly things. Once the cat discovers that there are fun things beneath the surface, he will continue to look for them.
Earthworms are natural borrowers,as they burrow they excrete.those excretions help provide nutrients to various botanical species.
earth worm has a fluid that ozees out and keep earthwor skin dry
Nutria
Some do. The sand boa (all subspecies) is a burrower along with Rosy boas and some others. The Red tail boa (which is probably what you're thinking of) is semi arboreal to arboreal and does not burrow.
Yes, they do it at night to keep themselves warm.
They burrow under ground.