Do you remember The Incredible Hulk? I’m dating myself. It was a TV series of an ordinary man that turned into a big green massive hulk of a man when he became angry. Bill Bixby (he of Courtship of Eddie's Father) turned into Lou Ferrigno.
More recently, in Harry Potter some characters could turn themselves into an animal form at will. Sirius could turn himself into a wolf, Pettigrew into a rat. 😏
These are fanciful transformations. But this type of transformation actually happens in nature. It is called metamorphosis.
I’ve been thinking lately about how I usually perceive animal abilities through the lens of being human. Such as - the cheetah can run so much faster than humans because it needs to. Evolution gave it incredible speed to catch prey. Humans don’t need that speed as we have other ways to catch prey. Another - dogs have a sense of smell some say is 100,000 times better than humans. That is incredible, but we humans can smell well enough for our lives - we depend more on vision than dogs, so humans invested throughout evolution in that sense versus smell.
I think I was implying to myself that humans could have done that too, if we'd needed to.
Last summer when I was watching the gulf fritillary caterpillars on our passionflower vines (see that story here) become butterflies I started wondering about metamorphosis. What have humans emphasized through evolution instead of the ability to metamorphose?
I concluded Nothing! Metamorphosis is something humans have never done, cannot do. Then I realized there are many abilities non-human animals have that has never been in our human repertoire.
I now think of these types of abilities as “extra-human”. Outside of human. We humans have nothing comparable. Nature went in a completely different direction with these.
Let’s take a look at the extra-human talent of metamorphosis.
One definition of metamorphosis is “the process of transformation from an immature form to an adult form in two or more distinct stages.” OK. Sounds interesting, something I am used to thinking about.
Another definition of metamorphosis is “a change of the form or nature of a thing or person into a completely different one, by natural or supernatural means”. Natural when I think about nature? Supernatural when I think about humans?
There are basically two different kinds of metamorphosis - incomplete and complete. In my examples at the top, Bill Bixby turning into Lou Ferrigno would be loosely comparable to what is called incomplete metamorphosis. The transformed creature looks sort of like the original, but with some significant additions and deletions. With insects, eggs hatch into nymphs, which mature into adults that somewhat resemble the nymph.
The dragonfly nymph elongates it’s abdomen and develops wings to become an adult. I get that. Lots of creatures, even humans, further develop certain body parts as they mature. Doesn’t seem extra-human or supernatural.
Complete metamorphosis however is another story. The adult form is completely different than the larval form that hatched.
Like Sirius turning into a wolf.
If you would like to read more about the difference between incomplete and complete metamorphosis, here is a good article.
Until recently I thought that what was happening in a cocoon or chrysalis was that the caterpillar was developing wings, antenna, etc. And that seemed pretty amazing. But it’s not that ‘simple’.
Inside the cocoon/chrysalis the caterpillar actually digests itself and turns into a soup. Then redevelops as a butterfly. 😳 Imaginal disc cells, which have been inside the caterpillar all along, survive the digestion and use the soup to power the formation of a butterfly. 🤯
Scientific American has a great article about this process by Ferris Jabr written August 10, 2012. Here is an excerpt.
“How does a caterpillar rearrange itself into a butterfly? What happens inside a chrysalis or cocoon?
First, the caterpillar digests itself, releasing enzymes to dissolve all of its tissues. If you were to cut open a cocoon or chrysalis at just the right time, caterpillar soup would ooze out. But the contents of the pupa are not entirely an amorphous mess. Certain highly organized groups of cells known as imaginal discs survive the digestive process. Before hatching, when a caterpillar is still developing inside its egg, it grows an imaginal disc for each of the adult body parts it will need as a mature butterfly or moth—discs for its eyes, for its wings, its legs and so on. In some species, these imaginal discs remain dormant throughout the caterpillar's life; in other species, the discs begin to take the shape of adult body parts even before the caterpillar forms a chrysalis or cocoon. Some caterpillars walk around with tiny rudimentary wings tucked inside their bodies, though you would never know it by looking at them.
Once a caterpillar has disintegrated all of its tissues except for the imaginal discs, those discs use the protein-rich soup all around them to fuel the rapid cell division required to form the wings, antennae, legs, eyes, genitals and all the other features of an adult butterfly or moth.“
Here is a short kind of icky video of this happening with a blowfly.
This is amazing. Beyond anything I ever thought was happening. And it is the normal course of events for butterflies and even the ever so lowly blowfly.
Extra-human. Super-natural. Humbling. Wonderful.
P.S. Here is a chart of most of the butterflies we see in South Carolina.
Though it does leave out one of my favorites, the Zebra Longwing.