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Deinonychusand its dino congenator may not have used their foul , curved claws to thresh about and draw their victims ; alternatively , these fearsome hunters may have used these pincer to pin and hold on their helpless prey .
In novel research , scientists detect the flushed - legged seriema ( Cariama cristata ) , a South American predatory boo that stalk small mammals , reptiles , amphibians and worm and which has a sharp , curved claw that sit down above the ground , much likeDeinonychus , Velociraptor , Utahraptorand other " raptor"dinosaurs . Two captive seriemas — Ellie at the Wildlife World Zoo , Aquarium , and Safari Park in Phoenix , Arizona , and Ernie at the Tracy Aviary and Botanical Gardens in Salt Lake City , Utah — were find immobilize and grasping quarry and unfamiliar physical object with these sharp claws .
The wicked curved claw of the red-legged seriema (Cariama cristata) is held off the ground so that it always stays sharp.
The observations add up weight to ahypothesisfirst suggested by paleontologistDenver Fowlerin 2011 , said study co - authorBrian Curtice , a fossilist at Fossil Crates , a troupe that makes museum - quality dodo casts . Fowler and his fellow argued that rather than slashing , these claw were good atgrasping wriggling prey and pinning it downfor easier consumption .
" This claw is not built for thresh about , to rephrase a the boot - walking song , " Curtice recount Live Science . " It was doing something else . "
Killer claw
violent - legged seriemas are one of the few living wench that have sharp , curving claws on their 2nd digit that bet much like the pincer of dromaeosaurid dinosaur , a group of feather theropods that includesDeinonychusandVelociraptor .
Unlike the velociraptors made famous by the " Jurassic Park " franchise , factual velociraptors were turkey - sizing . DeinonychusorUtahraptorare closer in size of it to the dinos that stalked Dr. Grant in the movie . ( In fact , thevelociraptors in Jurassic Parkare actually ground onDeinonychus . ) Jurassic Park also popularize the notion that these dinosaurs used their curve claw to cut down at prey as freehanded or larger than themselves , but paleontologists have long been skeptical of that idea . As it reverse out , dromaeosaurid claws do n’t resist side - to - side force well , saidJames Napoli , a palaeontologist and postdoctoral researcher at the North Carolina Museum of Natural Sciences and North Carolina State University who was not involved in the newfangled study . Nor do they make great knives .
" If you ’re using something to cut , you usually apply a straight blade , you do n’t expend a big sheer hook , " Napoli told Live Science . " And it does n’t have serration on the bottom , it ’s rounded , so there ’s not even a bring down surface . "
Ellie the seriema pins a keychain with her curved claw and pulls at it with her sharp beak, much as she might tear apart an actual prey animal.
Paleontologists began to propose other room the dinosaur could have used their claw , from climb to immobilize and comprehend prey . These ideas are gruelling to test , since dromaeosaurids are , of course , extinct . But Curtice got the musical theme of using the seriema as a modern comparison one solar day after taking photos of the birds at the Phoenix zoo . He noticed that the " kill chela " of the chunga look very velociraptor - like . These birds are native to grasslands in South America that would have been similar to the habitats where many dromaeosaurids roamed . And a bit of background signal reading showed that there had been small scientific bailiwick of how the birds used their claws .
Pin and tear
Curtice arranged the research project with the head of the menagerie in Phoenix , gaining license to go into Ellie the seriema ’s cage to take note her . Though the birds are only about 2.9 feet ( 90 centimetre ) tall and consider perhaps 4 pounds ( 1.8 kilograms ) , their claws and astute beak are intimidating , Curtice said .
" When you take the air in the cage and they close it behind you , it ’s probably how an MMA fighter feels , " he said .
Ellie promptly attacked Curtice ’s tv camera lens . But her keeper soon distracted her with the experimental objects , a keychain and a safety ophidian . To Curtice ’s joy , the razzing pounced on both , wallop the fake snake against a rock as if to kill it . In both typesetter’s case , she used her knifelike second claw to pin the objects to the ground while she tore at them with her beak . The research worker tookpictures and videoto document the behaviour .
TheVelociraptorsin the 1993 movie Jurassic Park were based on the dinosaurDeinonychus.
Curtice and his fellow recapitulate the observations with the seriema Ernie in Salt Lake City , who also demo off his pinning - and - grasp acquirement on bushed computer mouse . The razzing would pin the mouse to the ground with its claw and then rip off clump of physique to eat , Curtice said .
Seriemas in all likelihood are n’t perfect analogues toDeinonychusand other bird of prey . They hold their penetrating nipper off the flat coat with a sarcoid padder , while the dinosaurs ' toes were held in that place by bone . It ’s possible that there are some anatomical differences between the two that could change the function , Napoli said , though it ’s likely that both extinct dinosaur and New seriemas utilise the nipper in a exchangeable manner .
— Dino - era bird had the fountainhead of a Velociraptor and beak of a toucan
— Ravenous meat - use up dinosaurs gumption preserved in exceptionally rare fossil
— Scientists discover the earliest grounds of a dinosaur deplete a mammal
To learn more , Curtice and his colleagues go for to study the black - legged Chunga burmeisteri ( Chunga burmeisteri ) , a bird similar to the red - legged interpretation , to see if they also use their nipper to pin and compass . They also plan to do more detailed anatomical written report using digital 3D models that can mimic the movement of limb based on their bone .
" We know how seriemas use their foot and their hook , " Curtice said , " So now we can take a three - dimensional CAT scan of the gorgeous feet of the velociraptors and the troodontids [ bird - corresponding dinosaurs interrelate to dromaeosaurids that also have killing claws ] , and count at what kitchen stove of motion really allows , what could happen . "
The finding were published Jan. 5 in theJournal of the Arizona - Nevada Academy of Science .
