The tuatara, a New Zealand reptile, stands out in several different ways:

• They have a third eye on the top center of their heads.
• They have two rows of teeth on the top of their mouths that overlap the single row of teeth on the bottom.
• They are able to hear, even though they have no external ear.
• They have between 5 and 6 billion base pairs of genes in their DNA, compared to the 3 billion in human DNA.

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