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Michael Deak

@slothfultyrant.bsky.social

140 followers 92 following 150 posts

Adjunct professor at Youngstown State University who specializes in theropod and sloth thermoregulation and integument. He/Him, all opinions are my own.

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Michael Deak @slothfultyrant.bsky.social · Jan 14

Words cannot describe how excited I am to announce the publication of my first peer-reviewed paper published in the Journal of Mammalian Evolution! Here's a big, fancy thread summarizing everything: link.springer.com/article/10.1...

Metabolic skinflint or spendthrift? Insights into ground sloth integument and thermophysiology revealed by biophysical modeling and clumped isotope paleothermometry - Journal of Mammalian Evolution

Remains of megatheres have been known since the 18th -century and were among the first megafaunal vertebrates to be studied. While several examples of preserved integument show a thick coverage of fur...

link.springer.com

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Michael Deak @slothfultyrant.bsky.social · 1d

@tetzoo.bsky.social gives us the "skinny" on recent developments in megathere integument among other things regarding sloths extinct and extant. tetzoo.com/blog/2025/10...

Sloth World, 2025 (Part 1) — Tetrapod Zoology

Like me, you are no doubt a big fan of sloths...

tetzoo.com

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Michael Deak @slothfultyrant.bsky.social · 3d

Mmmm..... chocolate.....

a cartoon of homer simpson with his mouth wide open

ALT: a cartoon of homer simpson with his mouth wide open

media.tenor.com

Michael Deak @slothfultyrant.bsky.social · 20d

The first dinosaur eggshells from the Lance Formation. As for its identity, it could come from anything from Edmontosaurus to T. rex.
www.app.pan.pl/article/item...

The first description of dinosaurian eggshell from the Maastrichtian Lance Formation, Wyoming, North America - Acta Palaeontologica Polonica

www.app.pan.pl

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Michael Deak @slothfultyrant.bsky.social · 20d

@edgescience.bsky.social is putting something together to commemorate #120YearsofTrex. Anyone is free to contribute by sending in a video ansering the question "What does T. rex mean to you?" youtu.be/WWqawo1qwAA?...

TYRANN-O-THON | T. rex turns 120! Let's Celebrate ALL OCTOBER LONG!

YouTube video by EDGE Science

youtu.be

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Michael Deak @slothfultyrant.bsky.social · Aug 22

Great and nuanced take on the matter! That said, they should have probably waited a little bit before putting this together.

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Michael Deak @slothfultyrant.bsky.social · Aug 17

Now this is interesting! @grahancock.bsky.social, I would love to chat if possible.

Alberta Claw @albertonykus.bsky.social · Aug 17

#DinoConUK @grahancock.bsky.social: How to hide a T. rex

Michael Deak @slothfultyrant.bsky.social · Aug 16

There is a cooling trend in Hell Creek with the lower half of the formation being warmer than the upper half. Mean annual temperatures fell within 10-15 °C (50-60 °F). The supplementary materials to Bell et al. (2017) lists MAT ranges for Tyrannosauroid-bearing localities.

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Michael Deak @slothfultyrant.bsky.social · Aug 16

Granted that would likely not apply to juveniles >1000 kg. Not to mention that there is some overlap between the ambient temperatures of the Hell Creek and Yixian formations.

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Michael Deak @slothfultyrant.bsky.social · Aug 3

Do you want to know something funny? John Hammond funded InGen through a grift in the Jurassic Park novel. Colossal's "dire wolves" are the real life pachyderm portfolio.

Darren Naish @tetzoo.bsky.social · Aug 1

You’ll all have seen the many announcements and PR pieces from #ColossalBiosciences. There are reasons to be concerned about the general message promoted by CB, one being that it is seen >by some< (US politicians in particular) as meaning that we can devalue conservation. A 🧵 1/n

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Michael Deak @slothfultyrant.bsky.social · Jul 6

But here's the thing, we now know that dinosaurs "originated* in cold climates. The original #JurassicPark was an amalgam of the Dinosaur Renaissance, but Rebirth took dinosaurs back to being the "evolutionary failures" of decades prior. t.co/gvhqeBkRwq

https://www.science.org/doi/10.1126/sciadv.abo6342?fbclid=IwY2xjawLXQ85leHRuA2FlbQIxMQABHg4HVZdDuTk6V8x3JOqzOJxxNM0TB_ANoEC4ZfGikYXzt35ji1cr2iAg-Z9d_aem_0K6JOk5fiYztrduKZUHk4A

t.co

Michael Deak @slothfultyrant.bsky.social · Jul 6

Just saw #JurassicWorldRebirth last night, and you know what "really" irked me: The animated segment playing in the museum stating how the "Neo-Jurassic age" proved catastrophic for the dinosaurs, because they couldn't adapt to cold climates.

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Michael Deak @slothfultyrant.bsky.social · Jun 20

With #Jaws50 falling on a #FossilFriday, the gaping jaws of 0. megalodon at
@ripleysaquariums.bsky.social of The Smokies is an appropriate showcase!

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Michael Deak @slothfultyrant.bsky.social · Jun 10

Yet more evidence against the scale/feather false dichotomy in the form of scaly hands and feet in #pterosaurs in addition to previous publications showing that they were fuzzy too!
www.scup.com/doi/10.18261...

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Michael Deak @slothfultyrant.bsky.social · Jun 6

Forget Dracula and Edward Cullen, Lazlo Cravensworth is the vampire that all guys should aspire to be.

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Michael Deak @slothfultyrant.bsky.social · May 29

Very interesting review paper on dinosaur physiology. Plus it's the first (proper) citation of our ground sloth thermoregulation paper! This is going to come in handy for preparing the sequel.

Stephanie Baumgart, PhD 🦖🦆 @stephanopteryx.bsky.social · May 29

What can we learn about dinosaur physiology? 200 years after the 1st dino was named, new technologies yield amazing data from fossils. Physiology is vast, we hit on a few topics & gave ideas for improving hypotheses regarding how dino bodies may have worked. 🌡❤️🫁🦕🦖🧪⚒️🪶
doi.org/10.1098/rsbl...

Text: dinosaur physiology: what has been done and what could be done next. Image is a sauropod with a heart icon and a question mark, an ankylosaur with a thermometer and question mark and CFD model on its head, and theropod with bird lungs with a question mark.

Michael Deak @slothfultyrant.bsky.social · May 23

And if any of the authors of Boscaini et al. (2025) are reading this (and I know a few of you have already checked it out on ResearchGate), feel free to give our paper. I'd be more than happy to collaborate on a "sequel": link.springer.com/article/10.1...

Michael Deak @slothfultyrant.bsky.social · May 23

But in the end, we may have been the ones who did them in. Overall, I'm very pleased to see that some of our points overlap, and there is a lot of work that is left to be done on the evolution of body size and metabolism in #sloths as a whole.

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Michael Deak @slothfultyrant.bsky.social · May 23

With that said, I do think that either of these hypotheses are not mutually exclusive. The extinction of competitors and the changing climate together gave rise to the largest of the "X-men", with their low-ish metabolisms providing useful in various environments.

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Michael Deak @slothfultyrant.bsky.social · May 23

And while gigantism in sloths could be related to the drying and cooling of their environments, this may only be part of the story given that astrapotheres and high browsing notoungulates went extinct by the early Pliocene, which is when the biggest sloths evolved.

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Michael Deak @slothfultyrant.bsky.social · May 23

What is really interesting to me is that megatheroids were recovered to be ancestrally semiarboreal. Does this mean that the low core body temperatures that we recovered for large megatheres in Deak et al. (2025) via clumped isotopes an evolutionary holdover?

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Michael Deak @slothfultyrant.bsky.social · May 23

The findings suggest that #sloths evolved into giants at least three times independently, and large body sized coincided with cold climates, and that humans were a likely cause of the extinction of ground sloths.

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Michael Deak @slothfultyrant.bsky.social · May 23

A new paper by Boscaini et al. provided some interesting insights into the evolution of body size in sloths, and why the large ones went extinct. Some of the points that the authors raise align with some of our findings back in January (possible 🧵) .

www.science.org/doi/10.1126/...

The emergence and demise of giant sloths

The emergence of multi-tonne herbivores is a recurrent aspect of the Cenozoic mammalian radiation. Several of these giants have vanished within the past 130,000 years, but the timing and macroevolutio...

www.science.org

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Michael Deak @slothfultyrant.bsky.social · May 22

If Colossal wants to salvage its reputation with the scientific community, their PR department needs to have long talks with their scientists before they go spouting things off in the press.

Dr. Stephanie @punkrockscience.bsky.social · May 22

This is turning into a fascinating example of how the scientists need to talk to the marketing people and the investment people right from Day 1.

Messaging to non-scientists is important!

Colossal scientist now admits they haven’t really made dire wolves

Despite a huge media fanfare in which Colossal Biosciences claimed to have resurrected the extinct dire wolf, the company's chief scientist now concedes that the animals are merely modified grey wolve...

www.newscientist.com

Michael Deak @slothfultyrant.bsky.social · May 20

Is it Prehistoric Planet quality? No. Am I still looking forward to seeing it? Yes.

Michael Deak @slothfultyrant.bsky.social · May 18

Well Gale you are an odd fellow.....