The Secret Biology of the Easter Bunny

Image Credit: Tim Reckmann, CC BY 2.0, Image Cropped

Having an 8-year old when Christmas, Easter, or a lost tooth rolls around can be a tricky thing. You obviously don’t want to ruin the magic of these childhood landmarks, but at a certain point it kind of feels like you’re lying to them.

Luckily I enjoy a bit of speculative ecology (see: this take on the Tooth Fairy and our entire podcast), and the mystery of a rabbit that lays eggs presents a great opportunity to have some fun. So here’s my poorly thought-out version of the Easter bunny, or Pasquelatis lagomorphus.

Monotreme Madness

Obviously as an extant mammal that lays eggs, the Easter Bunny can’t be anything other than a monotreme*. Monotremes are though to have split from placental (eutherian) mammals about 140-170 million years ago, but despite this as of right now there are only five described species of monotreme (four echidnas and the platypus). So why not have another group of monotremes branching off at some point?

Read More: The Evolution of Monotreme Chromosomes

The problem then becomes how they became known worldwide, given that almost all non-placental mammals are found south of the Wallace line, a biogeographical line that runs through Indonesia. Yet given that monotremes branched off from eutherian mammals before marsupials did, it’s not impossible to think that early monotremes made it to the other side of the Wallace line (especially given that echidnas are thought to have evolved from an aquatic ancestor).

Convergent Evolution

All we rely on from that point onwards is convergent evolution. A species simply needs to evolve to fill a similar niche to a rabbit, such that they look relatively similar (relatively being an important point, as since we have no confirmed sightings of an Easter bunny it’s difficult to know how superficial the likeness is). This has happened across different continents many times over, with Australian quolls filling a similar niche to cats, Asia and Europe both playing host to completely unrelated species of magpies, and dolphins, icthyosaurs and sharks all having the same basic body plan. Bilbies and bandicoots in Australia and the South American mara both look somewhat like a rabbit, and it’s probable more genera throughout Earth’s history have taken a similar form.

Potentially Pathetic Parenting

Given our obsession with eggs at Easter, people must have been coming across P. lagomorphus eggs for a long long time. So why is our understanding of their physiology so poor? Easter bunnies must be prone to abandoning their young, a trait which received a bit of attention two years ago when Quokka parenting came under the spotlight. A few choice memes suggested that Quokkas threw their babies at predators to avoid being eaten themselves. While this is not exactly true, Quokkas still are pretty rubbish parents, abandoning their young to distract predators. As Professor Matthew Hayward shares in this article, “this makes evolutionary sense because the mum is a proven breeder, whereas the young may be infertile”. Sounds like a trait that could explain an abundance of eggs being found accompanied by a distinct lack of adults.

I am of course far from the first ecologist to have a crack at Easter bunny ecology. Speculative ecological artist Mette Aumala had a fantastic take on the beast recently, with the result linked here.

Have your own take on the Easter bunny or know one that deserves more attention? Send it through, as I thoroughly enjoy this mildly nonsensical brand of ecological science. Hope everyone had a Happy Easter.


Dr. Sam Perrin is a freshwater ecologist who completed his PhD at the Norwegian University of Science and Technology who is clearly very worried about Christmas 2021. You can read more about his research and the rest of the Ecology for the Masses writers here, see more of his work at Ecology for the Masses here, or follow him on Twitter here.

*My wife’s mother insists it’s a normal rabbit, but seeing as she’s allergic to rabbits and has not once had an allergic reaction around Easter-time this is clearly false.

2 comments

  • My daughter was in kindergarten when she lost her first baby tooth. She brought it home wrapped in a napkin with instructions from her teacher to ask mommy and daddy why are baby tooth fell out. I told it it was caused by the burrowing larva of the tooth fairy, and she went back to school the next morning and told her teacher that. At some point later in the morning as my wife was making herself some coffee the phone rang, and her teacher politely asked her to come to school for a little conference.
    Ah well.

    Like

    • This is a really interesting take on the Tooth Fairy! I’m assuming the idea was that when tooth fairies emerge from the tooth they leave eggs in nearby teeth?

      Like

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