Tigra

Tigra is a lesser-known superhero with a somewhat convoluted origin, but she does join the Avengers in issue #211. Unfortunately, her stay with the Avengers is a brief one, and she leaves the team in issue #216. While an Avenger she does not yet have a tail, nor does she have additional super-abilities like regeneration, which she apparently gains at a later date. She does have heightened senses, but they are not good enough to prevent Captain America from sneaking up on her.