The forests of Northern California can be perilous. Having a dangerous reputation
can mean the difference between life and death.
Even if that reputation is… well… not exactly true.
The yellow-eyed Ensatina salamander happens to look a lot like its very toxic neighbor
– the California newt. So predators think twice before chowing down.
When threatened, the ensatina even tries posing like a newt, flashing bright warning colors
on its belly.
But this ensatina is a phony. It’s not poisonous like the character it pretends to be.
Hundreds of miles away in the mountains, you’ll find one of its many relatives,
the Sierra Nevada ensatina.
It uses a completely different defense: disruptive patterning. Patches of high-contrast colors
make it harder for a predator to figure out where the ensatina’s body ends and where
the forest floor begins.
These two very different-looking ensatinas are actually members of the same species.
That means they can, and do, mate and have offspring in places where their ranges overlap...
... and they aren’t the only two branches of this eclectic family tree.
Ensatinas are a part of a sprawling clan of salamanders, separated and shaped by place
and time, evolving different ways to avoid predators.
Scientists think millions of years ago, ancestors of our yellow-eyed friend began moving down
the West coast of North America.
Their newt disguise became more convincing with each generation. The more they looked
like poisonous newts, the better they fared.
For our spotted pal, its ancestors took a different path; inland, along the forest floors
of the Sierra Nevada mountains. They passed splotches that helped them survive from generation
to generation.
Still other types of ensatinas developed more subtle patterning, which helped them blend
in with their surroundings.
Surprisingly, this motley crew can all have fertile offspring with one another.
But two members of this family – the Large-blotched ensatina and the Monterey ensatina –rarely
mate and have offspring in places where their ranges overlap.
Researchers think, over millions of years, as the ensatinas branched and spread south,
they diverged a little too much.
Now, some combination of behavior, where they like to live, and genetics, is molding them
into two separate species.
Ensatina salamanders are an example of a “ring species:” an animal that spread and adapted
around a geographic barrier – in this case, the dry California Central Valley – only
to come back together millions of years later as near strangers.
Over this stretch of time, ensatinas have continued to adapt to the places and predators
where they’ve spread.
But during that long journey, the branches of the family tree went separate ways.
Typically, the in-between versions of species fizzle out long before we can observe them,
but with a ring species like the ensatina, we get to see the steps it takes to become
a new species.
It’s evolution in action, a rare glimpse of how one species becomes many.
Hi, it's Laura. Do you need more cute, creepy, colorful creatures? Deep Look's got 'em. The
ferocious Mantis shrimp is definitely not afraid to stand out – or afraid anything,
really. And squid can change how light bounces off their skin, to create dazzling patterns
or uncanny camouflage. Enjoy, and see you next time!