Anne Hilborn Profile picture
Mar 27, 2018 24 tweets 14 min read Twitter logo Read on Twitter
NEXT UP: 3rd seeded Dimetrodon limbatus vs 7th seeded Pseudaelurus quadridentatus (aka Puff quaddy or Puffy) #2018MMM
This battle is a collaboration between @je_light & myself. #2018MMM
In R1 (seems so long ago, right?), Dimetrodon & Puff quaddy both took out extinct primates. Dimetrodon (early synapsid around ~300-260 mya in the Permian Period) shredded an exposed, & much smaller, Aegyptopithecus zeuxis (early catarrhine primate) #2018MMM
Puff quaddy (early cat around ~20-8 mya in the Miocene Epoch) made an easy meal of Archaeoindris fontoynontii (Indy, a recent, extinct lemur) #2018MMM
Did you know that both Dimetrodon limbatus & Pseudaelurus quadridentatus are type species? Type species are useful for the naming & placement of animals into groups (taxonomy); they are THE go-to reference & help researchers classify organisms #2018MMM
Remember Dimetrodon is not-yet a mammal (& is not a dinosaur) w/ a diagnostic sail on its back. Recent research hypothesizes the sail did not evolve to facilitate thermoregulation, but it could have evolved as a signal used in sexual selection…) #2018MMM
Pseudaelurus is regarded as the ancestor of all modern cats. Although this cat group originated in Europe, it dispersed to North America ~18 mya ending a ~8 million year #CATGAP in felid fossils #2018MMM
Dimetrodon limbatus were large (~150kg & 5.5m), ectothermic, terrestrial predators. The lineage leading to Dimetrodon rapidly evolved large body size during the late Carboniferous (300 mya) #ActualLivingScientist @kirstisaur… #2018MMM
Puff quaddy, in comparison, were substantially smaller, ~30kg, endotherms. Large, ectothermic Dimetrodon & smaller (yet, decent-sized), endothermic Puff quaddy differ in their temperature regulation & metabolic needs… #Foreshadowing #2018MMM
Tonight's battle takes place in Dimetrodon’s home turf, what is now Archer County, Texas. Both Dimetrodon & Puff quaddy were typically active at night (nocturnal;…) & both are on the prowl for food #2018MMM
As our scene opens, Ophiacodon (early synapsid like Dimetron but smaller) is resting on land, eyes closed & breathing slowed, digesting its last meal (I do a similar thing every Thanksgiving) #2018MMM
Puffy was probably an ambush predator like most modern cats. Although he is comfortable in the trees, he isn’t picky about where he finds his food, & this succulent Ophiacodon seems like just the ticket to fill his belly #2018MMM
As an endotherm, Puff quaddy requires 5-10x the amount of food than an
ectotherm of similar size. Puffy ate extremely well in R1 (Indy
was a large meal), but he needs more food to sustain his high internal
body temperature…
Using the vegetation as a screen, crouching low & freezing whenever Ophiacodon opens an eye, Puffy creeps closer.

When he is within 10m, he bounds towards Ophiacodon, applies a crunching bite to the back of the neck, his canines piercing the skull
& he has a meal #2018MMM
He drags the carcass back into the vegetation (modern felid species like cougars & leopards drag their kills to cover before eating), & uses his #carnassials to shear flesh from bone #2018MMM……
Nearby, Dimetron heard the kerfuffle & moving as softly as he can, comes to investigate. He sees Puffy crouched over the kill, face buried in the abdominal cavity, crunching on the ribs & not being particularly vigilant #2018MMM
The tradeoff between eating & vigilance is one most animals have to make. Medium bodied cats are not always very vigilant even when predators might be around. My work shows single male cheetahs spend only ~12% of time on a kill being vigilant #ShamelessSelfPromotion #2018MMM
Dimetrodon doesn't need that much food to sustain itself, but the small primate snack from R1 wasn't enough for provide sufficient energy to its 150kg frame; stealing Ophiacodon would be a nicely sized meal #2018MMM
The crunching of bones covers up Dimetrodon’s approach. Even in shortish vegetation, Puffy would have to sit up to look around him, & he is still crouched down to eat (not being vigilant). Though Dimetron is low-slung, he can see over the vegetation & watch Puffy #2018MMM
When he is close enough, Dimetrodon charges in. Caught with his head down, Puffy makes an awkward backwards leap. But Dimetrodon still has speed from his charge & Puffy only has a split second to evaluate his options #2018MMM
Puffy can’t use his usual attack method of jumping on the back + neck bite because of the vast sail in the way! A strangulation bite might work, but Dimetrodon has a very short powerful neck & even with Puffy's noticeable canines, it would be hard to get a grip #2018MMM
Puffy very quickly decides that fleeing is the best option. He scrambles backwards, then getting his feet under him, turns and speeds away. Once at a safe distance he glances back to see Dimetron ripping hunks of flesh out of Ophiacodon #2018MMM
As Dimetron gulps down the last of Ophiacodon and moves off to find dessert, a ripple of relief runs over Puffy's shaggy pelt and he is grateful that at least this time it wasn't him #2018MMM

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More from @AnneWHilborn

Mar 29, 2018
NEXT UP: Second seed Cheetah (Acinonyx jubatus) vs third seed Crabeater Seal (Lobodon carcinophaga) #2018MMM
Last time the cheetah vanquished the aye aye leaving naught but a finger behind and the crabeater seal made a furry pancake out of jaguarundi. #2018MMM
Will the curse of the aye aye cripple the cheetah this round? How will the seal cope with a much larger less squashy cat? Are you sitting comfortably? Then let’s begin. #2018MMM
Read 17 tweets
Mar 23, 2018
NEXT UP: 2nd seeded Cheetah (Acinonyx jubatus) vs 10th seeded Aye Aye (Daubentonia madagascariensis) #2018MMM
In the last battles, the cheetah ate the dunnart and the aye aye unnerved the coatimundi so much it retreated. Our scene is once again the Serengeti plains and once again the (still) hungry cheetah is being followed by a researcher named Anne. Aye aye pic=Nick Garbutt #2018MMM
The sun is setting. Cheetahs are mostly active during the day and Anne had based much of her PhD fieldwork on the idea that they would stay put at night to avoid lions and hyenas. Whoo-ee was she wrong (a theme for her PhD). Turns out cheetahs can move a lot at night #2018MMM
Read 19 tweets
Mar 20, 2018
First Up Tonight we have #16 seeded Belo Horizonte Marmoset vs. #1 Harar Hyena! #2018MMM
Despite it’s long neck and loping stride, the spotted hyena (Crocuta crocuta) is not a cross between a bear + dog as some people claim. The family (Hyaenidae) is more closely related to cats than the dogs. Spotted hyena range over much of Africa #2018MMM
Black tufted marmosets (Callithrix penicillata) are small new world monkeys (about 1.5 stoats/350 g). They live in family groups of 4-14 individuals in central Brazil and forage for fruit, flowers, leaves, young stems, tree resin, and insects #2017MMM…
Read 15 tweets
Mar 15, 2018
NEXT UP: Cheetah (Acinonyx jubatus) vs Fat-tailed Dunnart (Sminthopsis crassicaudata)! #2018MMM
Our battle takes place on the plains of the Serengeti, in Tanzania in East Africa. A mixture of open plains and woodlands, Serengeti National Park covers 15,000 km2, 5,700 square miles, or the area equivalent to millions of flatted stoats. #2018MMM #StoatsAsmeasurement
The Serengeti ecosystem is a stronghold for cheetahs in Tanzania, and @SerengetiCheeta has been monitoring them there since 1980. They estimate there are about 250-300 in the ecosystem, but that is a rough number since cheetah are hard to count. #2018MMM
Read 17 tweets

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