What kind of animal is a Yoshi?

Our current exhibition Strange Creatures: The Art of Unknown Animals features images, specimens and objects all related to how animals are represented through time. The exhibition is centered around George Stubbs’ painting of a kangaroo, an iconic image despite the fact that he never saw a kangaroo first hand. From dodgy taxidermy, dinosaur toys, glass models and wildly inaccurate images of animals which were claimed to have been studied from life, the exhibition explores how we make sense of a newly discovered animal species from first encounters with living animals through to reconstructions made from written accounts and sketches. Initial encounters with kangaroos drew comparisons with more familiar mammals such as jerboas, greyhounds, mice and deer, the creature so strange to European explorers it didn’t fit within existing classifications.

What happens if we start from an animal that we only know from a reconstruction? In the past (and today) mermaids, unicorns, giants, cyclopses, goatsuckers and deathworms have all been speculatively described either due to pervasive myths, hoaxes, delusions or confusion with other animals. To help with the process of working out how we identify animals we know from reconstructions alone, let’s see if we can work out how we’d classify a well known fictional animal, Nintendo character Mario’s companion and steed Yoshi*, this one acquired in a Happy Meal and currently on display in our exhibition.

Description

So what kind of creature is a Yoshi? It’s probably prudent to start with what we know about Yoshis. Fortunately, (as this handy and comprehensive Wikipedia page tells us, a page longer than all the pages for the underwhelming fossil fish put together) Yoshi has appeared in a number of video games. Described as either a dinosaur or dragon, Yoshis are four-limbed bipedal animals with a tail which have a shell-like saddle and a chameleon-like tongue. They have four digits on each hand and feet which resemble boots (which they are born with). Confusingly, yoshis hatch from eggs as either fully grown animals or as baby Yoshis and possess the unique ability to swallow other animals and birth/excrete them inside an egg. Yoshis can also turn into eggs and roll around. Yoshis appear in a variety of colours including green, yellow, pink, blue, red and light blue. Yoshis can also grow/use wings they find in the Mushroom Kingdom to fly for brief periods of time. Yoshi is capable of a range of vocalisations including making a noise which sounds like “Yoshi”, perhaps where the name came from.

Comparative Anatomy

As with any new discovery we start by looking at features shared with other animal species as a possible basis for comparison and inferring a taxonomic relationship. Yoshi is certainly a weird one with features we find in disparate groups across the animal kingdom. Assuming that Yoshi has an internal bony skeleton, (like other Mushroom Kingdom fauna such as dry bones and Dry Bowser), and because they lay eggs with a thick shell we can be fairly confident that Yoshi is an amniote tetrapod that is to say a vertebrate that isn’t an amphibian or a fish. However, other amniotes lack the ability to excrete prey inside a shelled egg or in fact turn themselves into a giant egg so this is perhaps a unique feature to Yoshis.

Now that we’ve ruled out amphibians and fish, we need to see if we can place Yoshi within mammals, birds or reptiles. Yoshis do fly with feathered wings but these are wings they find in boxes around the Mushroom Kingdom so is more highly advanced tool use than a physiological trait. They don’t appear to have teeth but also don’t have beaks so let’s assume they aren’t birds. From the available evidence Yoshis don’t appear to have hair or nipples, so they probably aren’t mammals (although some mammals have secondarily lost hair- think whales, dolphins and sparsely haired animals like elephants and rhinoceros.

So the case is looking strong for Yoshis being some kind of reptile but which? They have an extendable tongue like chameleons do but their legs are held directly underneath the body like dinosaurs and other archosaurian reptiles. They also have a reduced shell similar to turtles and tortoises while other denizens of the Mushroom Kingdom, such as koopas and the King of the Koopa himself Bowser, have more turtle-like shells. Again making the assumption these are related and conveniently ignoring Bowser’s tufts of hair, spiked shell and fire-breathing, Yoshis are probably some kind of turtly archosaurian reptile. Which is great as turtles themselves are turtly possibly-archosaurian reptiles, the exact relationship of turtles and related extinct reptiles to other reptiles continues to fluctuate. One last consideration is that from images of the undead skeletons of dry bones and Dry Bowser, the limbs appear to articulate outside of the rib cage, on the front actually, whereas modern turtles have limb girdles tucked inside the rib cage so it’s possible that Yoshi may be related to or convergently evolved to resemble pareiasaurs.

Needs More Research

What further information would be useful to help us narrow it down further? A skeleton would really help –  particularly a skull – as the teeth, if any, bones of the jaw and the number and position of holes in the skull would help confirm a reptilian identification. A skin sample would be really useful particularly to see if Yoshis have scales or have secondarily lost scales. A DNA sample would also be useful but given the current ambiguity around turtle and tortoise affinities may not be conclusive. Currently, the conservation status of many Mushroom Kingdom species is unknown but given the widespread harvesting of eggs and shells for power ups in karting, tennis matches and many others competitive sports some they may be at risk.

In the meantime, speculate away in the comments as to what kind of animal a Yoshi might be and who knows, in another 200 years there may be an exhibition at how wrong we were.

Mark Carnall is the Curator of the Grant Museum of Zoology

* The comparison might be less tenuous than you initially assume. With the Internet being a place where people with niche interests can find each other, in the weirder corners you can find communities of people who swear that they have actually seen unicorns, Pokémon,  and even pink fairy armadillos wandering around.