{"id":267926,"date":"2025-03-27T10:56:07","date_gmt":"2025-03-27T10:56:07","guid":{"rendered":"https:\/\/news.talkwithrattan.com\/index.php\/2025\/03\/27\/what-is-a-dinosaur\/"},"modified":"2025-03-27T10:56:07","modified_gmt":"2025-03-27T10:56:07","slug":"what-is-a-dinosaur","status":"publish","type":"post","link":"https:\/\/news.talkwithrattan.com\/index.php\/2025\/03\/27\/what-is-a-dinosaur\/","title":{"rendered":"What is a dinosaur?"},"content":{"rendered":"<div style=\"text-align:center\"><img decoding=\"async\" src=\"https:\/\/i3.wp.com\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1440_what_is_dino_tree.png?ssl=1\" class=\"attachment-post-thumbnail size-post-thumbnail wp-post-image\" alt=\"What is a dinosaur?\" title=\"What is a dinosaur?\" \/><\/div><p> <br \/>\n<\/p>\n<div data-component=\"video-embed\">\n<aside class=\"sn-conversion rich-text alignright\"\/>\n<p>Visit your local natural history museum gift shop and you\u2019ll probably find a container of dinosaur toys for sale. Dump out its contents, though, and you\u2019ll likely find some imposters, says Nathan Smith. He should know. He\u2019s director and curator of the Dinosaur Institute in California. It\u2019s part of the Natural History Museum of Los Angeles. Winged pterosaurs are a common fraud. So is the sail-backed carnivore, <em>Dimetrodon<\/em>.<\/p>\n<p>The word \u201cdinosaur\u201d isn\u2019t a catch-all term for just any scaly, prehistoric giant. \u201cThere\u2019s kind of a misconception that any big extinct thing was a dinosaur,\u201d Smith says.<\/p>\n<p>In fact, dinos are a specific group of reptiles. They have been around continuously for more than 200 million years. They include everything that\u2019s descended from the earliest common ancestor of avian (bird) and nonavian dinosaurs, Smith explains.<\/p>\n<p>Nonavian dinosaurs include such iconic beasts as <em>Triceratops<\/em> and <em>Tyrannosaurus rex<\/em>. Emerging in the Triassic, nonavian dinosaurs dominated the planet during the Mesozoic Era. This later era \u2014 also known as the Age of Dinosaurs \u2014 lasted until the close of the Cretaceous Period some 66 million years ago. Scientists suspect that\u2019s when <a href=\"https:\/\/www.snexplores.org\/article\/reliving-last-day-dinosaurs\">an asteroid wiped out about 80 percent of all animals<\/a>.<\/p>\n<p>Not all dinosaurs vanished after this impact, though. Some birds survived. They evolved into the more than 11,000 species of dinosaurs that roam Earth today.<\/p>\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1440_what_is_dino_tree.png\"><\/a><figcaption class=\"wp-element-caption\"><span class=\"caption wp-caption-3152702\">Birds are included in the dinosaur family tree. They belong to a group called theropods, which also includes <em>Tyrannosaurus rex<\/em>. Pterosaurs often get grouped in with dinosaurs because they lived at the same time, but they are not actually dinosaurs.<\/span><span class=\"credit wp-credit-3152702\">ILLUSTRATION BY STEVE MCCRACKEN<\/span><\/figcaption><\/figure>\n<h2 class=\"wp-block-heading\">Some reptiles became birds<\/h2>\n<p>Birds first arose some 160 million years ago. They descended from small, meat-eating dinosaurs similar to<em> Velociraptor <\/em>(<a href=\"https:\/\/www.snexplores.org\/article\/feathered-fossils\">of <\/a><a href=\"https:\/\/www.snexplores.org\/article\/feathered-fossils\"><em>Jurassic Park<\/em><\/a><a href=\"https:\/\/www.snexplores.org\/article\/feathered-fossils\"> fame<\/a>)<em>.<\/em><\/p>\n<figure class=\"wp-block-image alignright size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"597\" height=\"450\" src=\"https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_velociraptor-597x450.jpg\" alt=\"a model of the velociraptor used to film Jurassic Park\" class=\"wp-image-3152699\" srcset=\"https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_velociraptor-597x450.jpg 597w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_velociraptor-508x383.jpg 508w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_velociraptor-247x186.jpg 247w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_velociraptor-768x579.jpg 768w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_velociraptor-770x580.jpg 770w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_velociraptor-263x197.jpg 263w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_velociraptor.jpg 1030w\" sizes=\"auto, (max-width: 597px) 100vw, 597px\"\/><figcaption class=\"wp-element-caption\"><span class=\"caption wp-caption-3152699\">The <em>Velociraptor<\/em> made famous by the <em>Jurassic Park<\/em> movie franchise, a model of which is pictured here at Universal Studies in Hollywood, probably doesn\u2019t accurately depict the species. The filmmakers most likely based the movie version on\u00a0<em>Deinonychus<\/em>, a dino twice its size.<\/span><span class=\"credit wp-credit-3152699\">Emma McIntyre\/Getty Images Entertainment<\/span><\/figcaption><\/figure>\n<p>So if birds descended from dinosaurs, does that make them reptiles? Evolutionarily speaking, yes.<\/p>\n<p>Traditionally, animals have been classified based on their physical features alone. Under this system, birds \u2014 warm-blooded and covered in feathers \u2014 were separated from scaly, cold-blooded reptiles. Today, most researchers instead organize living beings by their evolutionary relationships.<\/p>\n<p>And new findings are offering better insights into the origin of birds. This has allowed researchers to trace bird ancestry back to their ancient dino ancestors.<\/p>\n<p>Some hallmark features of today\u2019s birds \u2014 such as feathers \u2014 came from nonavian dinosaurs. Meanwhile, certain traits set them apart from other reptiles. Consider the pygostyles (PY-go-stiles). These fused backbones support a bird\u2019s tail feathers.<\/p>\n<p>\u201cBirds are a subgroup of dinosaurs,\u201d says Smith. \u201cAll of those are then a subgroup of reptiles. Birds are dinosaurs in the same way that bats are mammals.\u201d<\/p>\n<h2 class=\"wp-block-heading\">Who isn\u2019t a dino?<\/h2>\n<p>Understanding how dinosaurs evolved can help weed out the imposters.<\/p>\n<aside class=\"wp-block-sciencenews-inline-related-post alignleft\">\n<h4><a href=\"https:\/\/www.snexplores.org\/article\/explainer-the-age-of-dinosaurs\">Explainer: The age of dinosaurs<\/a><\/h4>\n<\/aside>\n<p>For instance, pterosaurs are close relatives to dinosaurs. But the two groups split from one another during the Triassic, more than 235 million years ago. Meanwhile, <a href=\"https:\/\/www.snexplores.org\/article\/real-sea-monsters\">marine reptiles such as mosasaurs, plesiosaurs and ichthyosaurs<\/a> aren\u2019t closely related to dinosaurs, says Smith. Indeed, all true dinosaurs lived on land. But some, such as <a href=\"https:\/\/www.snexplores.org\/article\/dino-bite-leaves-tooth\"><em>Spinosaurus<\/em><\/a>, may have stalked ancient wetlands and beaches.<\/p>\n<p>And <a href=\"https:\/\/www.snexplores.org\/article\/prehistoric-meat-eater-preferred-surf-turf\"><em>Dimetrodon<\/em><\/a>? It wasn\u2019t a reptile at all. This distant relative of the ancestor of mammals lived about 50 million years before the first dinosaurs.<\/p>\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\">\n<p><div class=\"youtube-embed\" data-video_id=\"muWYY9qMM1A\"><iframe loading=\"lazy\" title=\"Why Isn&#039;t Pterodactyl a Dinosaur?\" width=\"696\" height=\"392\" src=\"https:\/\/www.youtube.com\/embed\/muWYY9qMM1A?feature=oembed&#038;enablejsapi=1\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/div>\n<figcaption class=\"wp-element-caption\">Those scaly pterodactyls sailing through Jurassic skies may look like dinos \u2014 but they aren\u2019t. This short video explains what sets the flying reptiles apart from ancient and modern dinos.<\/figcaption><\/figure>\n<h2 class=\"wp-block-heading\">Joined at the hip<\/h2>\n<p>Over tens of millions of years, dinosaurs evolved a dizzying array of sizes, shapes and adaptations. The most classic dino features have to do with how they moved, Smith explains.<\/p>\n<p>\u201cThese are animals that are bringing their limbs underneath their body,\u201d he says. \u201cThat involves changes in the hip bones and the leg bones.\u201d<\/p>\n<p>The top of their thigh bones \u2014 or femurs \u2014 turn inward to attach to the hip socket. Their pelvis features <a href=\"https:\/\/www.snexplores.org\/article\/defining-dinosaur-harder-ever\">a unique hole where the femur attaches<\/a>. Other prehistoric reptiles didn\u2019t have this opening in their hip.<\/p>\n<p>These traits gave dinosaurs an upright stance, with their legs placed under their bodies. It allowed them to spend less energy while moving. Even today\u2019s lizards, turtles and crocodiles (the closest living relative to dinosaurs) all stand with a more sprawling posture.<\/p>\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1030\" height=\"622\" src=\"https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_croc.jpg\" alt=\"a photo of the front half of a crocodile, as seen from the side, with mouth open wide\" class=\"wp-image-3152700\" srcset=\"https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_croc.jpg 1030w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_croc-634x383.jpg 634w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_croc-745x450.jpg 745w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_croc-308x186.jpg 308w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_croc-768x464.jpg 768w, https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1030_what_is_dino_croc-960x580.jpg 960w\" sizes=\"auto, (max-width: 1030px) 100vw, 1030px\"\/><figcaption class=\"wp-element-caption\"><span class=\"caption wp-caption-3152700\">Crocodiles and their relatives are the closest living relatives to dinosaurs. This close link means researchers today often look at crocodilians when studying ancient dinosaurs. Together with pterosaurs, the three groups belong to an ancient reptile line called archosaurs. <\/span><span class=\"credit wp-credit-3152700\">phototrip\/iStock\/Getty Images Plus<\/span><\/figcaption><\/figure>\n<p>This hip arrangement would have helped ancient dinosaurs occupy different niches, says ReBecca Hunt-Foster. It allowed smaller dinosaurs to make a speedy getaway from <a href=\"https:\/\/www.snexplores.org\/article\/scientists-say-predator-and-prey-definition-pronunciation\">predators<\/a>. <a href=\"https:\/\/www.snexplores.org\/article\/paleontologist-arkansas-dinosaur-fossil\">Hunt-Foster, a vertebrate paleontologist<\/a>, works at Dinosaur National Monument in Jensen, Utah.<\/p>\n<p>In dinosaurs too large to flee from danger, that unique hip structure also helped support their weight. Some, such as the <a href=\"https:\/\/www.snexplores.org\/article\/ankylosaur-dinosaur-tail-club-bash\">armored ankylosaurs<\/a> and <a href=\"https:\/\/www.snexplores.org\/article\/spiked-tail-rescue\">spike-wielding stegosaurs<\/a>, would have been weighed down by those defenses.<\/p>\n<p>This hip adaptation even helped support the sheer bulk of the <a href=\"https:\/\/www.snexplores.org\/article\/baby-titanosaur-was-mini-version-its-parents\">titanosaurs<\/a> \u2014 the largest land animals to ever live. Some may have reached a staggering 37 meters (120 feet) and tipped the scales at 70 metric tons. (One word of caution: So few bones from such behemoths have been found that <a href=\"https:\/\/www.snexplores.org\/article\/biggest-dino-ever\">calculating their true adult size remains fairly iffy<\/a>).<\/p>\n<section class=\"newsletter-signup__wrapper___lZ0W1 wp-block-house-ads wp-block-newsletter-signup\">\n<picture><source srcset=\"https:\/\/www.snexplores.org\/wp-content\/themes\/sciencenews-sns-child\/client\/src\/images\/cta-module@1x.png 1x,&#10;&#9;&#9;&#9;&#9;https:\/\/www.snexplores.org\/wp-content\/themes\/sciencenews-sns-child\/client\/src\/images\/cta-module@2x.png 2x\" media=\"(min-width: 768px)\"><source srcset=\"https:\/\/www.snexplores.org\/wp-content\/themes\/sciencenews-sns-child\/client\/src\/images\/cta-module-sm@1x.png 1x,&#10;&#9;&#9;&#9;&#9;https:\/\/www.snexplores.org\/wp-content\/themes\/sciencenews-sns-child\/client\/src\/images\/cta-module-sm@2x.png 2x\"><img decoding=\"async\" class=\"newsletter-signup__background___Eym8W\" src=\"https:\/\/www.snexplores.org\/wp-content\/themes\/sciencenews-sns-child\/client\/src\/images\/cta-module-sm@2x.png\" alt=\"\"\/><br \/>\n<\/source><\/source><\/picture>\n<div class=\"newsletter-signup__container___srNOL\" data-component=\"newsletter-signup\">\n<h3 class=\"newsletter-signup__heading___0EHmb\">\n\t\t\tEducators and Parents, Sign Up for The Cheat Sheet\t\t<\/h3>\n<div class=\"newsletter-signup__message___pemaq\">\n<p>Weekly updates to help you use <em>Science News Explores<\/em> in the learning environment<\/p>\n<\/p><\/div>\n<p class=\"newsletter-signup__thankyou___K6GGN\">Thank you for signing up!<\/p>\n<p class=\"newsletter-signup__error___hCsJI\">There was a problem signing you up.<\/p>\n<\/p><\/div>\n<\/section>\n<h2 class=\"wp-block-heading\">Hippie trait may explain dino diversity<\/h2>\n<p>Hip fossils don\u2019t just help researchers determine if an animal was a dinosaur. They also help explain how dinos diverged so greatly.<\/p>\n<p>Dinos belong to two major groups based on the shape of their lower hip bone, or pubis.<\/p>\n<p>In Saurischian (Soar-IH-shee-un) \u2014 or \u201clizard-hipped\u201d \u2014 dinosaurs this bone juts forward. Saurischians can be divided into two smaller groups: the meat-eating theropods (think <em>Tyrannosaurus rex <\/em>and <em>Deinonychus<\/em>) and long-necked sauropods such as <em>Brachiosaurus<\/em> and <em>Diplodocus<\/em>.<\/p>\n<p>The famous frilled dino <a href=\"https:\/\/www.snexplores.org\/article\/dino-drama\"><em>Triceratops<\/em><\/a> and <a href=\"https:\/\/www.snexplores.org\/article\/some-arctic-dinos-lived-herds\">herd-dwelling duck-billed hadrosaurs<\/a>, though, were Ornithischians. That term means \u201cbird-hipped.\u201d It came from 19th century scientists who noticed that the reversed pubis in these dinosaurs resembled those bones in birds.<\/p>\n<p>However, Smith notes, \u201cThat name has always been problematic.\u201d Why? Birds actually evolved from \u201clizard-hipped\u201d theropods. Birds would independently evolve a backward-facing pubis later. For Ornithischians, that reversed hip bone may have helped create more gut space. This would have let them digest massive quantities of plants.<\/p>\n<aside class=\"wp-block-sciencenews-inline-related-post alignleft\">\n<h4><a href=\"https:\/\/www.snexplores.org\/?p=203749\">Dinosaurs are alive (we just call them birds)<\/a><\/h4>\n<\/aside>\n<p>In the late 1800s, researchers proposed that these two types of hips must have come from different ancestors. But Smith says we now know all dinos evolved from one group of small, speedy dinosaurs that lived during the Triassic, about 230 million years ago.<\/p>\n<p>Scientists coined the term \u201cdinosaur\u201d in 1842. Back then, only a few species were known. Researchers assumed these ancient reptiles were clumsy, sluggish giants.\u00a0Since then, scientists have turned up about 1,000 nonavian species of this group. And some scientists suspect these represent only a fraction of all that ever lived. New species continue to be named each year.<\/p>\n<p>Their fossil remains have turned up on every continent. Understanding them is helping researchers better understand how these animals dominated most ecosystems for roughly 165 million years.<\/p>\n<p>It\u2019s also confirmed that <a href=\"https:\/\/www.snexplores.org\/?p=203749\">birds are, in fact, dinosaurs<\/a> \u2014 the only surviving ones. Like their ancestors, these living dinos are an evolutionary success. \u201cBirds occupy every single niche on every single continent,\u201d says Hunt-Foster. \u201cAnd they\u2019ve just kind of continued that from the Mesozoic.\u201d<\/p>\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\">\n<p><div class=\"youtube-embed\" data-video_id=\"69k-Cf5p80M\"><iframe loading=\"lazy\" title=\"Birds Are Dinosaurs: How a Dinosaur Family Tree Spans T. Rex to Pigeons\" width=\"696\" height=\"392\" src=\"https:\/\/www.youtube.com\/embed\/69k-Cf5p80M?feature=oembed&#038;enablejsapi=1\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/div>\n<figcaption class=\"wp-element-caption\">This short video shows where today\u2019s birds branched off the family tree from their reptilian ancestors.<\/figcaption><\/figure>\n<aside class=\"sn-conversion rich-text\"\/><\/div>\n<p><br \/>\n<br \/><a href=\"https:\/\/www.snexplores.org\/article\/what-is-a-dinosaur\">Source link <\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Visit your local natural history museum gift shop and you\u2019ll probably find a container of dinosaur toys for sale. Dump out its contents, though, and you\u2019ll likely find some imposters, says Nathan Smith. He should know. He\u2019s director and curator of the Dinosaur Institute in California. It\u2019s part of the Natural History Museum of Los [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":267927,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"tdm_status":"","tdm_grid_status":"","fifu_image_url":"https:\/\/www.snexplores.org\/wp-content\/uploads\/2025\/03\/1440_what_is_dino_tree.png","fifu_image_alt":"","footnotes":""},"categories":[606],"tags":[4648],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/267926"}],"collection":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/comments?post=267926"}],"version-history":[{"count":1,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/267926\/revisions"}],"predecessor-version":[{"id":267928,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/267926\/revisions\/267928"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/media\/267927"}],"wp:attachment":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/media?parent=267926"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/categories?post=267926"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/tags?post=267926"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}