Dead Serious: I Found Skulls on the Beach

I was raised at the beach, which means I’ve spent lots of my life combing for shells or watching jetty sunrises. But I’ve also had some atypical experiences on quiet off-season beaches: for example, finding not one but two skulls on the sand. And I don’t mean two skulls at the same time. I mean two totally different skulls, on different beaches, during different years and times of the year. (A live lobster washed up in front of me once on the beach, too, but no worries – another animal-loving local helped us free him back into the sea.)

Now, before anyone worries too much – neither skull that I found was human, and it appeared both has just washed up from the ocean since there were no other bones or anything around. But since I’m a biologist, I just couldn’t settle for “animal skull.” So I’ve been working on identifying the two of them. And it’s been a pretty cool learning experience.

Skull 1: The More Recent Find

This skull was between 4′-5′ in length and was found in December of 2020 on a tourist beach in the northeast U.S. The skull had obvious damage, although I’m unsure if this was related to cause of death or wear and tear from it’s time in the Atlantic. My first observations were the oval-shaped orbital bones, the well-preserved spaces for teeth at the rostral end, and the molars.

The shape of the skull immediately registered as mammalian, specifically a small mammal like a cat, a fox, a dog, or a raccoon. Past that I didn’t have much experience with animal bone shapes, so I hit up the internet.

Now, my very first and most rudimentary step was to check Google for images of fox, cat, dog, and raccoon skulls for comparison. Of course, though, I wanted to be more rigorous than just comparison, so I found information about dichotomous keys, which are essentially build-your-own-adventure style questionnaires to determine a skull’s species. There are also related general guidelines that may not give you an exact species, but will give you information on skull characteristics that can lead to solid conclusions about the skull. For example, an animal with molars likely didn’t eat only meat, and the location of where the spine enters the skull (the foramen magnum) helps determine the animal’s posture.

Take a look at the foramen magnum (circled in red) and the back teeth (molars, circled in blue). The molars, combined with the smaller tooth holes toward the rostral end, suggest to me that this creature was probably an omnivore. The location and angle of the foramen magnum allow me to imagine the angle of exit of the spine; we can see that it’s likely the spine was not perpendicular to the head, and so this was not an animal that walked around upright the way humans do. (Of course, the small mammals I had narrowed the skull down to I already know don’t walk this way, but it’s still good information to have.)

Now, skull shape came into play. The skull was not shaped the way a cat’s skull would be; I have a kitty, and her head isn’t shaped like that. This is where those Google images came in handy again – although I doubted this was a dog skull, I was unsure between fox and raccoon. I found convincing evidence from Skulls Unlimited and the Maryland Department of Natural Resources: what I had found was either a raccoon’s skull or a skunk’s skull.

Now the key was going to be the teeth. If the skull had “4-5 upper cheek teeth with less than 40 teeth total,” my skull would end up being that of a striped skunk. If it had “6 or more upper cheek teeth with 40-42 teeth total,” it would end up being a raccoon. I checked up on the definition of “cheek teeth,” and it indeed meant the molars and premolars in mammals (thanks, Wikipedia).

Now, I know from my job that premolars and molars are usually not all that different in size – at least not different enough to be able to fit in the empty tooth holes in front of the last existing cheek tooth in the skull. That means my skull only ever had the upper cheek teeth it was found with: 3 of them per side. An enigma. Plus, after checking out the forms of striped skunk skulls – this wasn’t the same shape I’d had in my hand! So, what went wrong?

Well, let’s think. It’s possible that I was wrong about the possibility of their having been more upper cheek teeth in the skull prior to it’s trip through the seas. It’s also more likely for there to be variability in number of teeth in individuals of a species than overall skull shape – some people have more wisdom teeth than others, but I don’t know any humans with snouts.

Based on all of this, my best guess without having some sort of weird séance and asking the skull itself is that this skull once belonged to a living, breathing raccoon. (Now, it’s been lovingly buried in the woods, where it belongs.)

Raccoon skull graphic, from Skulls Unlimited

Skull 2: Long-Gone Dragon

Now, this identification I went into without the expectation of hitting on an exact species, for a few reasons. First, I no longer have this skull. I found it years ago in Massachusetts, and because it smelled and I was a kid I wasn’t allowed to keep it for more than a few days. Second, I haven’t seen it in a long time, obviously. And third, it was weird. My best explanation of it is that it looked like a fantasy dragon skull, just way smaller.

A rudimentary sketch of the general shape I remember from the skull. Unfortunately, I don’t remember too much about the rostral end other than that it was slightly elongated.

My first thought was to first look into what I remembered the most strongly: the spines on the caudal end of the skull. I got what I expected: fish with weird structures in their skulls, mammal skulls that had nothing to do with what I was looking for, and dragon skulls – specifically a Game of Thrones art installation. And then this popped up in my Google images search: a damaged skull that automatically made my brain go PING! because it looks very similar to what I remember. The identifier believed it to be from a fish, but never got around to posting a species identification. So I emailed them.

While awaiting an email response, I dug through more google images and found that my memory of the old skull resembled skulls from the drum fishes. Searches seemed to keep revealing the black drum fish, a sort of cute creature I’d never heard of before. (If you look up the shape of their skulls, you’ll see that what my brain remembered, my hand did not do a good job of drawing!)

Zoology of New York, or the New York fauna, De Kay, James E. (James Ellsworth), 1842
Black drum fish image, courtesy of the Chesapeake Bay Program

I waited more than a week, and didn’t get any email response or any responses from other sources I asked. So it was time to dig deeper on my own. My thought was: what can I learn about the anatomy of the black drum to inform me on my specimen?

The three parts I was interested in regarding the black drum body were its (1) mouth, (2) operculum/pre-operculum, and (3) overall body shape.

The black drum has a rather beak-like mouth, great for eating hard prey. This makes sense since adults of this species eat things with shells, like crabs, living on the bottom of the sea.

This fish definitely has at least an operculum; you can see that along the orange dashed line in the image above. (The operculum and pre-operculum are two bony structures that protect the gills. Some fish have just the operculum, and some have both.)

The black drum is perch-like; in fact, its order is perciformes: perch-likes! Based on that information from Maryland DNR, images of black drums, and fish structure information from TSI, the black drum has a fusiform body shape. That’s a nice, hydrodynamic shape for a fish to have.

Operculum (yellow) and pre-operculum (red) from Wikipedia

Now, to connect this anatomy information to my skull specimen. If you look at the shape of verified black drum skulls, they are VERY weird – where are the eye holes? Why do they have caudal spines? Where are the bony structures of the operculum and, if there is one on this fish, the pre-operculum?

thanks, reddit

Keep in mind that these skulls have spent time in the open ocean and are damaged and sometimes only partial skulls. Also keep in mind that, apparently, these fish have been known to live for MORE THAN 50 YEARS. That’s an old smelly fish! They have lots of time to grow big, get hurt, etcetera, meaning a partial skull might tell only a very small part of that fish’s story. So here’s where I had the most fun: guessing about why the black drum has such an incredibly weird, fun skull!

Myrtle Beach Fishing and Reddit, respectively.

Take a look at the green line I’ve drawn outlining the drum’s head. You can see it has a narrower shape than you would first think looking at the fish; the area outlined in pink makes the face look larger but seems to just be flesh, not bone. You can see along the yellow lines some interestingly-shaped grooves along the drum’s head, which might explain the skull’s dragony appearance. The yellow dotted line on the skull approximates the area where these grooves are located on the critter. Now, the prominence just anterior to the eye on the living fish appears to follow the angle of the prominence I’ve outlined in orange on the skull, and I’ve used this to approximate an area where the eye socket of the dead fish may have been in life. It’s incredible to me that such a plain-looking fish can have such an extraordinary skeleton. ✿

Skull Identification Resource Guide

I’m not any kind of experienced critter-remains-identifier, so I needed some help to do this. Here’s what I used to guide me, in no particular order:

  1. Waking Up Wild’s Animal Skull Identification Guide
  2. Bone Identification blog on tumblr
  3. Skulls Unlimited article: “How to Identify a Skull”
  4. Sport Fishing article: “Amazing Bare-Bones Fish Art”
  5. Cornell University’s Naturalist Outreach: Presentation Resource Guide by Serina Brady
  6. Jake’s Bones
  7. Maryland Department of Natural Resources Key to Common Mammal Skulls
  8. Wikipedia: Cheek Teeth
  9. Bone Identification Tumblr Fish Skull Post
  10. Structure and Function of Fish from Exploring Our Fluid Earth
  11. Black drum skull post on Reddit
  12. Partial black drum skull (upper portion)
  13. Freshwater drum skull on Facebook
  14. Animal Diversity Pogonias cromis
  15. Images for reference:

Other Good Reads that Stemmed from this Research

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