The Weirdest Jellyfish

“Q: woa are upside down jellyfishs actually always upside down? how do they swim?”
— Anonymous

WELL MY FRIEND, they actually don’t! Or, not much, at least.

Some cnidarians (jellies & co) have a pretty neat adaptation in that they have an endosymbiotic relationship with zooxanthellae - a fancy way of saying that they have photosynthetic algae that live right inside of them. The algae gets protection and food in the form of waste, and the host gets delicious, delicious photosynthesized goodies.

Most true jellies do not, of course, entirely rely on photosynthesis, but Cassiopea jellies hang out in shallow water, and it works for them. They can swim, just like a normal jelly, but they usually prefer to just hang out. As a super bonus fun fact, because of this tendency to endlessly chill, they’re also a fairly common accessory for the carrier crab to cart around as protection

Photo from Tim Laman

Photo from Tim Laman

Even though you didn’t ask and likely don’t care*, coral (the “& co” part of Cnidaria) also has a pretty integral relationship with zooxanthellae! Coral is made up of millions of polyps (think perpetual baby jellies) that secrete a calcium carbonate skeleton - a skeleton that would be entirely white without the various species of algae living within. Endosymbiosis!! So perfect!!!!!

Photo from Shutterstock

Photo from Shutterstock

JUST KIDDING the relationship isn’t perfect, and depends on an extremely delicate balance. You’ve heard of “coral bleaching” (usually in conjunction with global warming), where wild corals are slowly losing their trademark colour  - which, when you take into account where that colour is coming from, is actually much more serious than it sounds**.

The stress of a change in water temperature can actually cause cnidarians to lose their cool (pun intended) and kick out the algae as a sort of last-ditch attempt to save themselves. This would be a great strategy if the stress was, say, an infection or parasite, and not the inescapable slow burn of the entire planet.

So the algae leaves, the coral starves, and millions of other organisms have to go find a new home. Except, of course, all the corals are doing it, so pretty soon there won’t be any homes to go to. Coral bleaching is no joke and I got super sidetracked from the whole point of this message but whatever


*But I care and that’s all that really matters so sit the heck down and get out your notebooks class

**This is facetious. How can you hear “bleaching” and think that doesn’t sound serious???? how do people still think this isn’t a big deal????? WHAT IS WRONG WITH YOU

Conservation Triage

“Q: could you tell us a bit more about conservation? like, what are the ‘truly integral’ species that we should be trying the hardest to protect?”
— Anonymous
“Q: In light of the pandas post, if I wanted to donate to some conservation effort, do you know if there are ones that make a “better” use of their money than others? ”
— Anonymous

When I call a species “more important”, that is, of course, a hella oversimplification, and you would be right in asking me but how can you really decide which ones are more important? Ecosystems are so complex and interconnected that, when it comes down to it, every species is important - but the loss of certain species would result in greater repercussions than others. For example:

  • Keystone species: a species whose presence affects a disproportionate number of other species, such as predators that control prey populations (sharks, sea otters)

  • Ecosystem engineers: sub-group of keystone species, these guys affect the environment in such a way that it drastically changes the resources available for other species (beavers, crocodilians)

  • Umbrella species: species that require such a large habitat that protecting them would mean thousands of other species would benefit from that protection (bison, or like, monarch butterflies)

  • Flagship species: this is the category the panda falls into - species that capture the hearts of the masses and garner loads of media attention and money; could also act as umbrella species

To protect species, we have to protect environments, and once again we get bogged down with nuances and priorities. Do we protect areas of high biodiversity, like tropical rainforests, where there are hundreds of species within a few metres of each other, that aren’t found anywhere else? Or do we protect areas of high population, like the Canadian boreal forests, where there are few species but so many trees that it stores twice as much carbon as a tropical rainforest?

Conservation is messy and overwhelming, and as I mentioned before, there’s never enough money or interest to protect everything. If you do want to help, do some research on your local zoos or aquariums - certain facilities will have programs for captive breeding, rescue work, research, or other environmental aid. For example, the Vancouver Aquarium runs a sustainable seafood program, and Monterey Bay Aquarium is just a conservation dreamboat, so supporting places like these means you can feel good and have fun all at once.

I don’t know of any independent conservation programs in particular to support over others - though I imagine programs like World Wildlife Fund, the IUCN Red List, and National Wildlife Federation are solid places to start. If anyone has some personal experience, though, I would be more than happy to pass it on.

Octopus of Many Talents

“So! I was wondering if you knew anything about the Indonesian Mimic Octopus. Apparently it can mimic 15+ different species like the lion fish or a flounder for defensive purposes, but I was wondering if it would have to observe these animals to mimic them or if its an instinctive evolutionary trait, or if it’s even known. I tried looking for resources but couldn’t find anything definitive. I know octopuses are a far cry from birds but I thought it was cool and was wondering if you knew any more”
— Anonymous

I couldn’t find anything directly relating to this either, unfortunately! According to the original paper of the description of the species, it was hypothesized that the ability to mimic certain shapes was genetic, but when to use each posture was a direct reaction to the current environment.

For example, the octopus would only use the posture resembling a highly venomous sea snake when faced with territorial damselfish - because the damselfish are commonly predated by that specific sea snake. 

Photo from NCBI

Photo from NCBI

It really isn’t that different from other cephalopods and their crypsis - most octopuses mimic surroundings, in terms of changing skin colour, texture, and form - so there is a genetic basis for it. The mimic octopus lives in a predator-heavy, open habitat, however, so there was likely strong selective pressure for an alternative to hiding as rocks or coral. Those who managed to resemble local venomous species were likely way more effective than those who didn’t.

They’re pretty cool though, and if anyone else knows more about them, I’d love to hear it!

Alligator Engineers

“Q: So what’s the point of a crocodile/gator? What contribution do they bring to the food chain? and such?”
— Anonymous

You mean besides just being freaking adorable dorks all the time????

Photo from Clayton Bownds

Photo from Clayton Bownds

Well my friend, I hope you are prepared for the long-winded summary on predator-prey population dynamics that you have unleashed here.

As a general rule, any apex predator is crucial to an ecosystem, specifically because they regulate population numbers of their prey species and leave remains that can be exploited by smaller animals. Crocodilians are typically the largest freshwater predator in their ranges, and due to their ambush hunting method and amphibious* lifestyle, they have a huge range of prey species. They will eat anything they can catch, of any size, including fish, amphibians, other reptiles, both large and small mammals, birds, people - the list goes on and on. But let’s get a bit more specific.

Alligators (both American and Chinese) are allogenic ecosystem engineers, meaning that - like beavers, caterpillars and woodpeckers** - alligators physically change their environment and, as a result, change the resource availability in those areas. Adult alligators will dig and expand “gator holes” that stay filled with water even during droughts, allowing tons of other species to survive dry periods.

Photo from EarthSky

Photo from EarthSky

On top of that, American alligators are currently the only predator large enough to make a dent in the invasive Burmese python population that is literally destroying the Everglades as we speak. Unfortunately, the predation goes both ways.

Photo from Reptipedia

Photo from Reptipedia

Crocodiles are a bit tougher to describe, mostly because there are a whole pile of species, but all are important in prey population control and particularly in scavenging carcasses. Crocodiles have the strongest stomach acid of any vertebrate, and as such can eat just about anything, including rotting carcasses that would otherwise pollute water systems. 

I’m not going to go into all of the species of crocodile, because it would take several weeks, but I will say that the saltwater crocodile is pretty neat - not only as the largest crocodilian, and the one with the largest range of prey species - but because it is currently the only predator in Australia that has been shown to be able to survive eating the highly toxic and invasive cane toad***. 

Even though you didn’t ask, I’m gonna just touch on the two other types of crocodilians, because I love them. Gharials are highly specialized crocodilians that would normally regulate fish populations - if they weren’t critically endangered - and caimans are smaller, highly adaptable crocodilians. Cuvier’s dwarf caiman in particular is a keystone species.

A couple other things about crocodilians to chew on:

  • Crocodilian meat and leather is a HUGE market, and is fueling conservation and breeding efforts that might otherwise not be there

  • Crocodilians are a very effective tourist draw (read: more conservation)

  • Abandoned nests turn into peat, also important for wetland ecosystems

  • Crocodile tears are a real thing but most likely not due to emotion

TL;DR: CROCODILIANS ARE SUPER IMPORTANT, MAINLY BECAUSE THEY EAT STUFF


*Except gharials. As a rule, gharials look pretty dorky on land.

**Humans are also technically in this grouping, but I didn’t want to insult alligators with the comparison.

***Not proven as a possible population control, however. Too bad.