An alarming message about deodorant use and breast cancer began circulating on the Internet in the 1990s, spread via e-mail and message-board postings. It continues to resurface now and again and causes a great deal of concern about the safety of items many of us use every day. So let's take a look at the evidence.
How long have sharks been in existence? A: Geological records show that modern shark species have existed for between 201 million and 174 million years. Earlier fish species similar to sharks existed as early as between 419 million and 359 million years ago.
Life Cycle. Every shark species has its own expected life span and so it is wrong to set an average for sharks as a whole. However, very broadly speaking, we can say that most sharks live for between 20 and 40 years. The Spiny Dogfish lives for over a century, and Whale Sharks are expected to be similar.