Unusually Large Caterpillar Turns Up In NJ – Is it native?

Even as someone who's in the woods a lot throughout the Garden State, and someone who gardens every season, it's always wild coming across something new. Even if it's something you've perhaps seen before, if you don't come across it often in your area, it's usually a surprise.

This was the case recently while walking home with my son. It was a nice afternoon in Monmouth County so we decided to hit the stores by foot instead of by car.

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The walk wasn't too long so it wasn't a big deal. Plus, we like to look for every excuse possible to not drive simply because, why drive if you don't have to?

Anyway, we were on our way back home when we came across this really fat, big green caterpillar. It's something I've never seen in my area before, but I know I've come across it in the past. I just couldn't place where.

Invasive, or native?

With so many invasive insects in New Jersey lately, I wasn't sure if this belonged here or not. So we watched it for a moment as it went across the sidewalk.

It was a bit of a slow mover, but at the time there wasn't much risk of it being stepped on. And that's good because if this is something native to New Jersey, I didn't want to be responsible for killing it.

I texted my mother-in-law to ask what it was since she's very big into nature and would probably know the answer. But right afterward, I did my own research.

What in the world was this? And was it native to the area? It didn't take long for me to get my answer.

Polyphemus moth caterpillar

This was the caterpillar of what would become a polyphemus moth. And yes, they are native to our part of the country, including here in New Jersey.

Now, I've never actually seen the moth in it's adult stage, but from what I understand about them, they are huge! Approximately 4 to 6 inches across actually, which is much bigger than your typical everyday moth.

Meant to scare predators

Here's something interesting about the polyphemus moth. That pattern on it's wings resembles eyes, which is said to scare away predators.

Not only that, but it's colorations blend in beautifully into the foliage. That, and they're also nocturnal, which is why some of us have never really seen them before. The caterpillars, on the other hand, do come out during the day.

Short life span

This rather large caterpillar we came across was probably getting ready to enter its pupa stage. Just to note, the caterpillar stage lasts approximately 6 weeks or so.

Then after the pupa stage, they emerge as full-sized adults. But here's another fun fact about this moth. It doesn't have a mouth.

In fact, it's life as an adult only lasts about a week. Long enough for it to mate and lay eggs before it dies. Without the ability to eat, it can only live on it's reserves once it emerges from it's cocoon.

Adulting for just a week

If you come across a giant, fat green caterpillar, this is what it most likely is. They are native to New Jersey, so yes, they do belong here (unlike the spotted lanternfly, which does not).

The polyphemus moth doesn't live long, so it's worth just letting it be. Kind of a cool find.

The above post reflects the thoughts and observations of New Jersey 101.5 weekend host & content contributor Mike Brant. Any opinions expressed are his own.