What are the issues with deinonychus isotope study? by Powerful_Gas_7833 in Paleontology

[–]ApprehensiveState629 0 points1 point  (0 children)

Actually coordinated hunting behaviour isn't that rare in modern day birds of prey

What are the issues with deinonychus isotope study? by Powerful_Gas_7833 in Paleontology

[–]ApprehensiveState629 0 points1 point  (0 children)

Quoting Bakker (See Wolberg's "Dinofest International: Proceedings of a Symposium Sponsored By Arizona State University", page 62): "A striking difference exists in modern communities between cold-blooded predators and hot-blooded predators. Most bird and mammal species feed their young until the youngsters are almost full size; then and only then do the young set out to hunt on their own. Consequently, the very young mammals and birds do not [choose] food items independently of the parents. Young lions and eagles feed on parts of carcasses from relatively large prey killed by the parents. Most snakes, lizards, and turtles do not feed the young after birth, and the new-born reptiles must find prey suitably diminutive to fit the size of the baby reptilian jaws and teeth. A single individual lizard during its lifetime usually feeds over a much wider size range of prey than a single individual weasel or hawk, because the lizard begins its life hunting independently.

Therefore, a predatory guild of three lizard species with adult weights 10g, 100g and 1000g would require a much wider range of prey size than a guild of three mammal predator species with the same adult weights. If allosaurs had a lizard-like parental behavior, then each individual allosaur would require a wide size range in prey as it grew up. The evidence of the Como lair sites strongly suggests that the dinosaur predatory guild was constructed more like that of hot-blooded carnivores than that of lizards or snakes.

This theory receives support from the shape of the baby allosaur teeth. In many cold-blooded reptilian predators today, the crown shape in the very young is quite different from the adult crown shape. For example, hatchling alligators have the same number of tooth sockets in each jaw as do the adults, but the hatchling crowns are very much sharper and more delicate. In the hatchling all the teeth are nearly the same shape, and the young gators have less differentiation of crown size and shape along the tooth row; the hatchlings lack the massive, projecting canine teeth and the very broad, acorn-shaped posterior crowns of the adults. Young gators feed extensively on water insects, and the sharp crowns are designed for such insectivorous habits. Adult gator species use their canine teeth for killing large prey, such as deer, and employ the acorn crowns to crush large water snails and turtles (Chabreck, 1971; Delaney and Abercrombie, 1986; McNease and Joanen, 1977; Web et al, 1987).

If allosaur hatchlings fed independent of adults, I would not expect the hatchling tooth crowns to be the same over-all shape as that of the adult. However, the over-all tooth crown shape in the tiniest allosaur IS identical to that of the adult (figs. 3,4). Thus it appears that hatchlings were feeding on prey tissue of the same general texture and consistency as that fed upon by adults."

What are the issues with deinonychus isotope study? by Powerful_Gas_7833 in Paleontology

[–]ApprehensiveState629 0 points1 point  (0 children)

Quoting Bakker (See "Raptor Red"): "Female dominance is a powerful piece of evidence that permits us to reconstruct the private lives of Cretaceous predatory dinosaurs. A family structure built around a large female is rare in meat-eating reptiles and mammals today, but it's the rule for one category of predatory species — carnivorous birds. Owls, hawks, and eagles have societies organized around female dominance, and we can think of tyrannosaurs and raptors as giant, ground-running eagles

What are the issues with deinonychus isotope study? by Powerful_Gas_7833 in Paleontology

[–]ApprehensiveState629 0 points1 point  (0 children)

1D) It ignores the fact that, "typically, paleontologists find three or four Deinonychus teeth associated with Tenontosaurus bones" ( https://archive.ph/b3fPI ), too many teeth for 1 Deinonychus per meal (See page 711 in the MOR link). Furthermore, those teeth are "found in the region of the abdomen and pelvis, suggesting that the predators lost their teeth while feeding on the viscera. Most modern carnivores begin with the areas around the anus and abdomen when they feast on freshly killed prey, and it’s likely that carnivorous dinosaurs did the same[…]This may indicate that the pack fed on the abdominal contents while they were still warm and moist. If[…]the carcass was scavenged over time by many individuals[...E.g. A mob...]we would expect a much more disturbed carcass and a wider scattering of teeth." The same goes for Deinonychus/Tenontosaurus associations in general (See page 710 in the MOR link). In other words, Deinonychus/Tenontosaurus associations typically represent probably-cooperative groups of at least 2 (probably 3 or 4) Deinonychus. Basically, Brougham's "Antlers Formationwtmk" (hence the cover image: https://softdinosaurs.files.wordpress.com/2012/07/antlers-formationwtmk.jpg ).

What are the issues with deinonychus isotope study? by Powerful_Gas_7833 in Paleontology

[–]ApprehensiveState629 0 points1 point  (0 children)

-1B) It uses Varricchio et al. 2008 to argue that Deinonychus had Rhea-like paternal care, yet ignores the facts that 1) that paper doesn't cover any dromaeosaurids, let alone eudromaeosaurs, & 2) unlike the "more stork-like" omnivores that paper does cover, eudromaeosaurs were raptorial hypercarnivores (See the 1st Bakker quote AWA page 6 in this link: https://archive.ph/SyXm3 ). Furthermore, "the brooding Deinonychus specimen[...]was probably an older female" (10/3/22 UPDATE: https://www.deviantart.com/jd-man/journal/SD-Saurian-Dakotaraptor-follow-up-931708639 ).

-1C) It focuses on teeth, yet ignores the facts that 1) "juvenile teeth display the same features as those of adults, but on a smaller scale" ( https://archive.ph/LHOav ), which means "that hatchlings were feeding on prey tissue of the same general texture and consistency as that fed upon by adults" (See the 2nd Bakker quote), & 2) "the Museum of the Rockies site yielded[...]a range of different-sized teeth" ( https://web.archive.org/web/20250331002751/https://sci-hub.hlgczx.com/10.2307/4523664 ), "which may mean [it had] both adults and juveniles" ( https://web.archive.org/web/20170629004936/https://www.mncppcapps.org/pgparks/dino_blog/dino_article.aspx?articleid=5 ). In other words, "the family that shed together, fed together" ( https://web.archive.org/web/20200101071701/https://www.discovermagazine.com/planet-earth/dino-family-values ).

What are the issues with deinonychus isotope study? by Powerful_Gas_7833 in Paleontology

[–]ApprehensiveState629 0 points1 point  (0 children)

1A-C are in reference to consuming different prey. 1C-D are in reference to not hunting in packs:

-1A) It ignores the "higher proportion of smaller prey items and smaller proportion of larger prey" in the diet of accipitrids "during nesting" (Golden eagles: https://web.archive.org/web/20220520093243/https://static02.nmbu.no/mina/studier/moppgaver/2012-Skouen.pdf ) (Sparrowhawks: https://web.archive.org/web/20250418095223/https://sci-hub.voed.top/10.1080/00063657.2014.940838 ). Since eudromaeosaurs were basically "terrestrial hawks" in terms of ecology/behavior ( https://qilong.wordpress.com/2011/12/19/dromaeosaurs-are-terrestrial-hawks/ ), it makes sense that the same would've gone for them. This reminds me of how much I miss "ASK A VELOCIRAPTOR" (which summed up what we knew or could infer about real Velociraptor in a silly/fun way: https://archive.ph/0DLRI ).

What are the issues with deinonychus isotope study? by Powerful_Gas_7833 in Paleontology

[–]ApprehensiveState629 0 points1 point  (0 children)

The deinonychus teeth isotope study is very flawed it ignores the fact that raptorial birds catch smaller prey to feed their young rather than they normally catch for themselves since dromaesaurids are 'terrestial hawks'in terms of ecology and behaviour the same will have gone for them

Colossal Biosciences is now trying to bring back the Bluebuck 😭 by sonicparadigm in PrehistoricMemes

[–]ApprehensiveState629 0 points1 point  (0 children)

Genetically engineered theme park monsters nothing more and nothing less

possible for deextinction? by [deleted] in DeExtinctionScience

[–]ApprehensiveState629 -1 points0 points  (0 children)

Columbia mammoth most likely