I may be the last person to learn these things, but just in case I’m not, I thought I would share them with you.
- Did you know that some jellyfish species are found in freshwater? I always thought that they were strictly saltwater creatures. These freshwater types are known as medusas (Craspedacusta sowerbyi). They seem to appear sporadically in blooms so they aren’t always there to observe.
Some scientists speculate that they are airlifted from their point of origin which is believe to be the Yantzee River and “deposited” by birds in lakes and streams. However, no one has ever seen a jellyfish attached to a duck, for example. You may think that this is a geographically isolated phenomenon but these jellyfish have been found in locations as distant as Australia, Chile, and in my home state of Maine.
- Because I never thought about it, I assumed that humans were the longest living mammals on the planet. That is incorrect. Bowhead whales (Balaena mysticetus) live to an average age of 200 years if we don’t kill them first. That’s still a brief lifespan compared to the Greenland shark (Somniosus microcephalus) which lives for 300 to 500 years. This is the longest living vertebrate animal, beating out the Galapagos Giant Tortoise (Chelonoidis niger complex) and Orange Roughy (Hoplostethus atlanticus), both of which live for up to 250 years.
- And while we are exploring some aquatic novelties, there is an 18-foot shark called the Megamouth Shark (Megachasma pelagios) that has been spotted only about 100 times, ever. Despite its enormous mouth, this shark has tiny teeth. It is a filter-feeder, eating only plankton and jellyfish.
Consequently, stories that the shark was discovered when it swallowed a US Navy ship anchor in 1976, may be an exaggeration. More likely, the shark became entangled in the anchor’s cabling.
Another unique feature of this deepwater shark is its silvery-white upper lip. At one time, scientists wondered if it was bioluminescent in order to lure its prey. Research conducted in 2020 uncovered that it was merely highly reflective. This is an interesting adaptation, nonetheless.
More about freshwater jellyfish — https://esajournals.onlinelibrary.wiley.com/doi/10.1002/fee.2343
More about freshwater jellyfish in Maine — https://www.maine.gov/dep/water/lakes/jelly.html
More about the age of various animals — https://safarisafricana.com/animals-that-live-longest/
For more information about the Megamouth — watch NatGeo’s World’s Weirdest, Season 5 Episode 3
Study about the bioluminescence study of megamouth —https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0242196