Living Fossil
Surviving largely unchanged across hundreds of millions of years, outlasting mass extinction events.
Atlantic Horseshoe Crab
A blue-blooded cousin of spiders and scorpions, with ten eyes and blood that clots when it meets certain bacteria.
Coelacanth
Thought to have gone extinct over 65 million years ago, then found alive in 1938, with fleshy fins that move like a four-legged animal's legs and a pregnancy of around five years, possibly the longest of any vertebrate.
Frilled Shark
A slow-swimming, six-gilled deep-sea shark whose lineage is estimated at 82 million years old and whose pregnancy may run three and a half years.
Sea Lamprey
A jawless survivor from a lineage that split from ours roughly 500 million years ago, armed with a sucker mouth ringed in rasping teeth.
Tuatara
The sole survivor of an ancient reptile order: a nocturnal New Zealand islander with a light-sensitive third eye it does not see with, and a sliding jaw that makes a shearing bite.