1993—Scientists discover that some shark fetuses engage in "embryophagy," a type of cannibalism in which they eat one another while still in the womb.

1993—The world's oldest shark fossil is unearthed in New Brunswick, Canada. The 409 million-year-old fossil is just nine inches long.

2003—Researcher Marsh Youngbluth is the first person to see a rare Greenland shark in the Gulf of Maine. This species is known to eat caribou, polar bears, and penguins.

2004—Great white sharks become the first to be protected under the Convention on International Trade in Endangered Species, which controls the trade of thousands of threatened animals and plants worldwide.

2005—Scientists discover that warm-blooded salmon sharks maintain their temperature by swimming continuously, allowing them to survive in the 47 degree Fahrenheit waters of the north Pacific.

2006—Scientists identify "walking sharks," which appear to walk on their fins across coral reefs, off the coast of Indonesia.

2006—Researchers estimate that up to 73 million sharks are killed each year primarily for the global shark fin trade.

2007—A study finds that continued shark overfishing in the United States could lead to an overabundance of cownose rays that feed primarily on shellfish, causing a collapse of scallop populations as a result of cascading effects of removing this top predator.

2009—The Pacific Island nation of Palau, declares a shark sanctuary throughout its waters, banning commercial shark fishing. Since then, five other countries have followed suit, protecting 1.8 million square miles of ocean.

2010—The Shark Conservation Act bans shark finning in U.S. waters. The Pew Environment Group's Shark Attack Survivors for Conservation were key advocates for this important law.

2011—Australian researchers discover that sharks may be color-blind, relying on contrast instead.

2012—Scientists find a neurotoxin in shark fins that is linked to Alzheimer's in humans.