Humans hunt sharks, but they also cause an unsafe environment when the fish for other fish. Sharks get caught on lines or in nets and die out that way. The natural threat is that they cannot reproduce enough young to keep a steady population rate if they die from accidental by-catch. It is also suggested that human suntanning oil or skin products entering the ocean via beaches draws the shark to hunt in grounds much closer to the shore. The mercury content in fish near the shore is great than that way out in the ocean, so these sharks are developing tumors. Since they are the top of their food chain, they do not get eaten by other animals, but it is known that Dolphins and Orcas attack sharks. They do this out of protection or the right for food since all creatures eat a lot of fish. Both the shark and orca eat sea lions and seals.
Work Cited: HowStuffWorks,Inc. (2012). Threats to Sharks. Retrieved From: https://greatwhitesbio.wordpress.com/wp-admin/post-new.php