Are black widow spiders known for being very aggressive and having fatal bites?

Black widow spiders are not characterized by aggression; they tend to be more reclusive and will generally avoid contact with humans. When it comes to their bites, although a black widow's bite can be dangerous and may result in serious medical issues, fatalities from bites are quite rare due to the availability of effective medical treatment. The correct understanding of their behavior is that they bite primarily in self-defense, especially when they feel threatened or provoked. Therefore, the statement suggesting that they are very aggressive and that their bites are typically fatal is misleading, confirming that the answer accurately indicates that they are not recognized for aggressive behavior or frequent fatal bites.