There are some core things about the mythical creatures I wish Meyer would have gegeven an actual explaination for:

Vampires

1. Turning into bats

She could have explained it as bats are attracted to vampires, but she choose not to adress it at all.

2. Sleeping in a coffin

How about that having something to do with them faking their own death of something?

3. Lack of Fangs

An evolution over time to adapt.

4. Sunlight

Related to the fact vampires are considered to be connected to the devil.

Werewolves

1. Full-Moon

They meet at the full-moon.

2. Their Anger Issues (yes, I know that some of the wolves have this)

It could have been explained as a reaction to the moons phases.

3. Pack- Mind

Evolved trait of even a gift from the spirits.