“…and today we’re talking about a fish that would shoot a guy in the back. But more on that later.”
Lurking in the low-lit lounge of the Pacific lies the spotted ratfish, this silvery weirdo skims the ocean floor, callously crunching crustacean carapaces. Part shark, part rabbit, part catfish thing, it glides around with the confidence of something that knows it’s packing a deeply unsettling surprise up top. A creature that proves the ocean’s design committee has a motto of “no bad ideas”, it pays to be weird in the water like the Spotted Ratfish here in Life, Death, and Taxonomy.
Taxonomy
It’s a chimaera, a close relative of sharks and rays, and belongs to a very old lineage that split off from sharks to make its own way.
Description of the Spotted Ratfish
People sometimes call it a “ghost shark” because of its big eyes, tapering tail, and silvery-brown body covered in white spots that give it a spooky, prehistoric look.
You can kind of see it’s shark kinship, but a quick look might just come off as some kind of fish.
Its base colors are dark grey, light grey, and tan.
Measure Up
Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com.
Most adults are about 2 to 3 feet long (roughly 60–90 cm).
They typically weigh 2–4 pounds (around 1–2 kg), though especially large individuals can be a bit heavier.
Fast Facts About the Spotted Ratfish
You’ll find spotted ratfish along the Pacific coast of North America, from Alaska down to Baja California.
They usually hang out in deeper coastal waters (roughly 100–900 feet), though they sometimes wander into shallower water at night.
They’re bottom-dwellers and feed on crabs, clams, worms, small fish, and sea stars, using strong, plate-like teeth to crush hard shells rather than sharp shark-style teeth.
Instead of separate dorsal fins like sharks, they have a large triangular pectoral fin that gives them a kind of slow, hovering flight through the water.
Their tails are long and whiplike, and males have some truly weird features, including a clasping organ on the head used during mating.
spotted ratfish do have venom, but not in the way people usually imagine. They have a venomous spine in front of their dorsal fin.
It’s defensive only—they’re not aggressive—but if handled carelessly, the spine can cause a very painful wound, with swelling and intense localized pain. It’s not considered life-threatening to humans, just extremely unpleasant.
Major Fact
- For almost all animals, teeth are strictly oral structures. Meaning that they belong in your mouth.
- For the spotted ratfish, they have a head structure called a tenaculum that flips the script
- That white thingy sticking out of their forehead is actually toothy hardware on its head
- These head-teeth are part of a specialized clasping structure, mostly used by males during mating.
- Solves the age-old problem of “how to hold onto a slippery date in the dark abyss.”
- The same cells that form teeth in their mouths also form the teeth on the tenaculum. These cells make up a tissue called dental lamina, making these true teeth rather than hardened bone or the denticles that sharks and rays tend to have.
- Males and females develop tenaculum, but only males grow it out fully and also garnish it with teeth
- Reinforces the universal marine rule: if it looks weird, it’s doing something important.
Ending
So skim the ocean floor, hang on for dear life, and make sure to remember to always brush your tenaculum teeth like the spotted ratfish here in LDT.