You Might Not Know This...

So here are some facts that I found while looking up information on sharks. I didn't know some of these and thought I would pass along the knowledge.

• Over 375 shark species have been identified, but only about a dozen are considered particularly dangerous.
  
• Three species are responsible for most human attacks: great white, tiger, and bull sharks.
• The largest shark is the whale shark, which can grow to 60 feet (20 meters) long.
• Among the smallest shark species is the deep water dogfish shark which measures less than 8 inches (20 centimeters) in length.
• Sharks do not sleep. Rather, they experience alternating periods of activity and rest.
• Some sharks must swim constantly to "breathe" oxygen from water passing through their gills. Other species can achieve this while stationary.
• Sharks are among Earth's most ancient animals. The fossil record dates ancestors of modern sharks to as far back as 400 million years ago.
• Sharks can replace lost teeth in as little as 24 hours and may use thousands of teeth over the course of a lifetime.

For these and other shark facts, click here.