It’s the start of October, and Halloween is approaching! Halloween brings chatter about spooky, mythical creatures like ghosts, goblins, witches, and vampires. Most people have heard of vampires, but few have heard of vampire squids! In honor of Halloween, let’s take a deeper dive into this fascinating creature. The vampire squid was given the scientific name Vampyroteuthis infernalis which translates to “vampire squid from hell”. Vampire squids range in color from red to black, with webbing between their arms that creates a bell-shaped body. At the tip of each arm is a specialized organ that produces bioluminescence. Additionally, each vampire squid has two thin tentacles or “filaments” that can extend from its body to explore the squid’s surroundings and sense food. Interestingly, the name “vampire squid” is misleading in two ways. First, vampire squids are not true squids, but are actually a type of octopus— the only living species in the family Vampyroteuthidae. Second, vampire squids do not eat blood like vampires, but instead feed on dead organic material, or “marine debris” that gets trapped on their extendable filaments by a secreted, sticky mucus. This diet is likely due to the environment they live in. Vampire squids inhabit the deep sea at depths of up to 2,500 meters where there is very little light and oxygen. As a result, there are very few species that inhabit the same area as vampire squids, but when animals higher up in the ocean die, their bodies sink down to the vampire squids’ depth. Additionally, remaining at these depths helps protect vampire squids from most predators. However, these squids can still be eaten by deep-diving creatures like sea lions, whales, sharks, and other octopi. One spooky feature of this species is that when a vampire squid’s arm is bitten off, it can regenerate and grow back! The vampire squid is one of many spooky, but amazing sea creatures, with many other species still left undiscovered!

As the season of all things spooky is upon us, it is more than fitting to pay respects to our undead friend of the sea. The immortal jellyfish is a unique example of biological perseverance since its lifespan is technically infinite! But what is the immortal jellyfish and how is it different to the jellyfish we know and love? The scientific name of this species is Turritopsis dohrnii, and its life cycle begins like any other jellyfish. The jellyfish develops from a floating larvae called a planula, which eventually settles on the ocean floor and grows into a polyp. When the polyp grows enough tentacles, they detach from the bottom of the ocean and live as an ephyra larva; from the free-floating larval stage they will grow to reach their final, mature form, the adult or medusa phase. So what happens next? The answer, as fascinating as it is, was discovered by accident!

The family Turritopsis was discovered in the late 1800’s, scientists taking note of its bright red stomach visible through layers of mesoglea (the jelly inside the jellyfish), and its small size, being a medusa being no bigger than a penny. It took around a hundred years for scientists to discover that this species of jellyfish has a trait that other jellyfish, and every other organism for that matter, lack. A few Turritopsis dohrnii polyps were placed in a tank and expected to grow into ephyra larvae and adult jellyfish, eventually reproducing. That would mean after some time they should return to adult jellyfish along with a few planula floating around the tank, right? What they recorded instead was a tank whose bottom was covered in polyps. Not expecting this result, they paid closer attention and discovered that the adult medusae would sink to the bottom of the tank and transform back into the polyp. Under stressful environmental conditions such as old age, lack of food sources, or sickness, the immortal jellyfish begins transdifferentiation, when its cells convert from one type to another By changing cellular function, in this case, the immortal jellyfish has reversed the biological clock. No bloodsucking or zombification required is for these sea creatures, the immortal jellyfish can now relive its life from the polyp stage, and as an added bonus, can produce ephyra offspring that are genetic clones to the original.

Since its seemingly supernatural immortal abilities were discovered, the immortal jellyfish has been a focus for scientists worldwide seeking answers and applications to human health. Could these jellyfish be the answer to curing cancer? Living longer? We don’t yet know, but there is no doubt that the marine undead will continue to surprise us.

David Attenburough once said about reptiles “(they) are sometimes thought of as primitive, dull and dim-witted. In fact, of course, they can be lethally fast, spectacularly beautiful, surprisingly affectionate and very sophisticated." On October 21st, we take the time to celebrate these fast, beautiful, and affectionate animals. National Reptile Day was created to raise awareness about the importance of these animals, and to take into account the threats they face. When thinking about these often obscured animals, it is equally important to remember marine reptiles, perhaps even less thought of than land-dwelling reptiles!

Marine reptiles are classified as reptiles who have adapted to living in or around water, so while there are roughly 12,000 species of reptiles, only 100 of those could be classified as marine reptiles. Some of the most popular marine reptiles are sea turtles, sea snakes, marine iguanas, and saltwater and american crocodiles. Several marine reptiles are extinct, and some date these animals as appearing as far back as 299 million years ago, like the Mesosaur; the Ichthyosauria and the Sauropterygia date back 250 and 247 million years ago, respectively. It should not come as a shock that similarly some of the currently living species of marine reptiles are threatened or endangered. 

There are 69 species of sea snakes, several of which are of threatened status. They are all venomous, except for 1 genera, and live predominantly in the Indian and Pacific oceans. This is in contrast to sea turtles, of which 7 species still exist, and of whom all but 1 species are classified as endangered or threatened. These turtles can be found all in all non-polar oceans, and all species aside from the flatback can be found in the US. One of the notable features about female sea turtles is that they come on land to expel their eggs; 50–350 eggs incubate for 50–60 days, then hatch with their sex determined by the temperature of the surrounding area. One of the many factors that threaten the existence of these turtles are the many things that can destroy their nests— human activity and animal activity make it so an average of just 1 hatchling survives until maturity. Predators, disease, bycatch, poor beach development, poaching, pollution, the effects of climate change, and oil spills are just some of the predominant factors impacting the status of sea turtles. However, several factors are currently assisting the sea turtle population, including attempts at conservation and decreased time on beaches due to covid-19. 

The marine iguana is a threatened species and is the only lizard species that lives primarily in a marine environment. They live in coastal colonies with a maximum of 200 occupants typically, and feed on algae in the environment. While scientists think many subspecies of marine iguanas exist, only 13 or so have been recorded, and 5 were additions as recent as 2017. Scientists hypothesize that the recent impact on the population of marine iguanas is due to oil spills, El Niño cycles, and predation from other animals. The American crocodile is similarly of a threatened status, declassified as endangered in 2007. They primarily occupy coastal regions and prefer salinity. It is estimated that only 5% of American crocodile deaths are from natural causes, attributing the majority of their deaths to human activity; from poaching, pollution, and loss of habitat, among other factors. 

On October 21st, be sure to remember marine reptiles! Not only are they some of the coolest reptiles, but they consist of some of the most vulnerable reptile populations. Many marine life and reptile organizations this time of year will be trying to help the reptile populations, so make sure to check out their projects and learn how you can do your part!