So, in the interest of accountability, in the interest of continuing to make my book useful for public education about shark science and conservation even as the science and policy landscape changes, and in the interest of keeping notes for myself for any future updated versions of the book, I have been keeping track of things that I wrote at the time that are no longer true, or weren’t quite right at the time. (Please note that some of these facts and figures were already out of date at the time the book was pubished, but that was well after the final text was turned in).
In the Last of Us, the most gruesome live-action adaptation of a video game about people being turned into fungus since 1993’s Super Mario Bros, a mutated species of Cordyceps destroys society by converting humans into mindless, sporulating mushroom people.
Cordyceps, a fungus that most commonly parasitizes ants, is real. It really does hijack its host’s nervous system, alter its behavior, and turn it into a spore-producing zombie. The outcome is strangely beautiful.
Though the current darling of gritty, realistic, science-based zombie fiction, Cordyceps is such a lightweight in the world of brain-breaking parasites that tech bros brew it into their adaptogenic coffee.
If you want to meet a truly unsettling zombie-making parasite, allow me to introduce you to Sacculina.
Sacculina is a genus of barnacle that parasitizes crabs. While most parasitic barnacles are perfectly happy growing on the carapace of a crab, Sacculina takes this partnership to the extreme.
Female Sacculina larvae drift through the ocean, until they encounter a crab. The larva then settles on the crab and searches for a joint in the crab’s carapace. Once it finds a gap in the arthropod’s armor, it transforms into a kentrogon, a specialized phase of the barnacle life cycle that possess a stylet–an organic syringe-like structure–which allows Sacculina to inject itself into the crab, and not much else. At this point, the hard shell attached to the crab’s carapace falls off and the barnacle continues to grown within its host.
When you live in the darkness of the abyss, finding a partner is hard and keeping a partner is even harder. Deep-sea anglerfish, one of the iconic ambassador species of the deep ocean, have found a novel solution to this problem–dwarf males are sexual parasites that latch onto the body of the much larger female anglerfish and then physically fuse to their partner, becoming permanently attached to the point where they share a circulatory and digestive system.
Parasitic dwarf males are uncommon, but not unheard of, throughout the animal kingdom. Osedax, the deep sea bone eating worm, also maintains a harem of dwarf males in a specialized chamber in their trunk. But few species, and no other vertebrates, go to quite the extremes of the anglerfish. And with good reason.
Vertebrate immune systems have a long shared history. The Major Histocompatibility Complex (MHC) is a suite of genes shared among all gnathostomes–the taxonomic group that contains all jawed vertebrates, from fish to fishermen. It creates the proteins which provide the foundation for the adaptive immune system, the core complex which allows bodies to tell self from no-self, detect pathogens, and reject non-self invaders. Suppressing the MHC seriously inhibits a vertebrate’s ability to fight off infection.
Incidentally, not all deep-sea anglerfish have parasitic dwarf males, and the species most often presented as a type specimen in the popular press, the humpback anglerfish Melanocetus johnsonii, is one of several that do not have permanently attached parasitic dwarf males. M. johnsonii males are free-swimming throughout their life, they’re just small and clingy.
Scientists (and sci-fi fans) have to varying degrees been discussing the concept of suspended animation for years; the idea that the biological functions of the human body can somehow be put on “pause” for a prescribed period of time while preserving the physiological capabilities. If you’ve ever watched any sci-fi movie depicting interstellar travel you have probably seen some iteration of this concept as a way to get around the plot conundrum of the vastness of space and space travel times, relative to natural human aging and human life span. The basic principle of suspended animation already exists within the natural world, associated with the lethargic state of animals or plants that appear, over a period, to be dead but can then “wake-up” or prevail without suffering any apparent harm. This concept is often termed in different contexts: hibernation, dormancy, or anabiosis (this last terms refers to some aquatic invertebrates and plants in scarcity conditions). It is these real-world examples that likely inspire the human imagination of the possibilities for suspended human animation. The concept of suspended human animation is more commonly viewed through the lens of science fiction (and interstellar travel), however, the shift of this concept from scientific fiction to science reality has a more practical human application.
The Emperor of all Maladies is how Siddhartha Mukherjee, an Indian-born American physician and oncologist, aptly described cancer. Cancer, this scourge of mankind going back as far as 4,600 years ago when it was identified by the Egyptian physician Imhotep (the first in recorded history). Cancer takes one of the most successful traits of complex eukaryotes, cell division, and weaponizes it in unchecked cellular growth; some even consider cancer to be a more evolved form of cell division. This ailment has plagued humanity, and baffled physicians for centuries as they attempt to tackle the seemingly impossible, discover a cure for cancer.
In 2001, on an expedition to hydrothermal vent fields in the Indian Ocean, researchers made a bizarre discovery. Clustered in small aggregations around the base of a black smoker was an unusual snail, seemingly clad in a suit of armor. Rather than a single, hard, calcareous structure, the snail’s operculum was covered in a series of tough plates. On recovery to the surface, those plates, as well as the snail’s heavy shell, began to rust. This was an Iron Snail.
The Rio Grande Rise is an almost completely unstudied,
geologically intriguing, ecologically mysterious, potential lost continent in
the deep south Atlantic. And it also hosts dense cobalt-rich crusts.
The Rio Grande Rise is a region of deep-ocean seamounts
roughly the area of Iceland in the southwestern Atlantic. It lies west of the
Mid-Atlantic Ridge off the coast of South America and near Brazil’s island
territories. As the largest oceanic feature on the South American plate, it straddles
two microplates. And yet, like much of the southern Atlantic deep sea, it is
relatively under sampled.
Almost nothing is known about the ecology or biodiversity of
the Rio Grande Rise.
Hagfish. You love them. I love them. Of all the fish in all the seas, none are more magnificent than the hagfish. Across the world, children celebrate the hagfish by making slime from Elmer’s glue, their own mucous, or just, like, something. Seriously, how is is that toddler hands are always coated in some strange, unidentifiable slime?
2018 was a big year in hagfish science. Below are just a few of my favorite studies.
A hagfish in the high Antarctic? Hagfish have previously never been observed in the shallow waters around Antarctic, but a photograph from 1988 was determined this year to be a hagfish feeding on a large pile of clam sperm in shallow water. Neat!
Incidentally, the reason the photo languished for so long is that it was originally though to be a Nemertean. Because Antarctic Nemertean worms are huge and horrifying.
Last month, while traveling to Kuching for Make for the Planet Borneo, I had an idea for the next strange ocean education project: what if we could use bone-conducting headphones to “see” the world like a dolphin might through echolocation?
Spoilers: You can. Photo by A. Freitag.
Bone-conducting headphones use speakers or tiny motors to send vibrations directly into the bone of you skull. This works surprisingly well for listening to music or amplifying voices without obstructing the ear. The first time you try it, it’s an odd experience. Though you hear the sound just fine, it doesn’t feel like it’s coming through your ears. Bone conduction has been used for a while now in hearing aids as well as military- and industrial-grade communications systems, but the tech has recently cropped up in sports headphones for people who want to listen to music and podcasts on a run without tuning out the rest of the world. Rather than anchoring to the skull, the sports headphones sit just in front of the ear, where your lower jaw meets your skull.
This is not entirely unlike how dolphins (and at least 65 species of toothed whales) detect sound. Read More
Big Ideas (the ecologic paradigms that hagfish shifted)
Heincke’s law is one of those ecologic principles that more often acts as a foil for rejecting the null hypothesis than as a consistent pattern in ecology. It’s most basic summary is: The further from shore and the deeper dwelling a fish is, the bigger it grows. Heincke’s law does not appear to be true for hagfish, whose size appear to have no relation to the depth at which they occur. On the other hand, phylogenetic relationships do seem to play some role in regulating body size in hagfish.
Defense and Behavior (how hagfish do the things that they do)
Hagfish are master escape artists, capable of squeezing in and out of tight spaces barely half the width of their body. This great for getting in an out of rotting whale carcasses on the sea floor, creeping into crevices, and avoiding predators. But how do they accomplish this incredible feat? Hagfish have a flaccid sinus under their skin which allows them to control the distribution of venous blood and alter their body width as they wriggle through narrow passages. Freedman and Fudge identified 9 distinct behaviors which take advantage of this adaptation, including anchoring, forming tight loops to push the body through an opening, and bending the hagfish head 90 degrees to force it through a slit. And there are videos!
The Fudge lab has been busy this year, cranking out some of the most noteworthy work on the incredible behavior of hagfish. In addition to examining hagfish motility, Boggett and friends looked into how those flaccid sinuses aid predator avoidance. The team build wee little guillotines loaded with shark teeth to see how hagfish skin protects the animal from vicious bites. In a year when a truckload of hagfish spectacularly crushed a car, the fact that this research was the biggest breakout sensation in hagfish pop culture says everything you need to know about the compelling results of this study. You can read more about this study at The Verge, Futurity, Popular Science, and plenty of other outlets.