Main content
Course: American Museum of Natural History > Unit 1
Lesson 2: How do scientists study dinosaurs?- Where in the world did dinosaurs live?
- Where in the world did dinosaurs live?
- Did dinosaurs travel in herds or packs?
- Did dinosaurs travel in herds or packs?
- How fast were dinosaurs?
- Were dinosaurs warm-blooded?
- Were dinosaurs warm-blooded?
- How fast did dinosaurs grow, and how long did they live?
- How fast did dinosaurs grow, and how long did they live?
- What was dinosaur skin like?
- What color were extinct dinosaurs?
- What color were extinct dinosaurs?
- What were the biggest and smallest dinosaurs?
- Did dinosaurs fight?
- How did dinosaurs reproduce?
- How intelligent were dinosaurs?
- New research points to dinosaurs' colorful past
- New dinosaur research: Microraptor's feather color revealed
- Quiz: How do scientists study dinosaurs?
- Exploration Questions: How do scientists study dinosaurs?
- Answers to Exploration Questions: How do scientists study dinosaurs?
© 2024 Khan AcademyTerms of usePrivacy PolicyCookie Notice
How fast did dinosaurs grow, and how long did they live?
Until recently, paleontologists could only guess about these questions. Because many extinct, non-avian dinosaurs, such as Tyrannosaurus and Apatosaurus, are so immense, it was generally assumed that they grew slowly and required 50-100 years to attain their great size.
Growth rings
But recent research involving microscopic analyses of the cellular structure of dinosaur bone has revolutionized our answers to these mysteries. Dinosaur bones contain growth rings, somewhat like the rings in tree trunks, which reveal yearly periods of rapid and slow growth. By studying growth rings in Tyrannosaurus bones, scientists can estimate how fast the animal was growing at different times in its life and how old individual animals were when they died.
These studies, done in conjunction with paleontologists at AMNH, document that that Tyrannosaurus, which attained a weight of more than 10,000 pounds as an adult, reached sexual maturity at about 20 years of age and lived for up to 28 years. In order to obtain its immense size and weight, it could put on almost five pounds a day during its phase of maximum growth. As one might expect, these rates of relative growth are fairly similar to those found in birds, which are the closest living relatives of Tyrannosaurus. Microscopic studies of these growth rings in Apatosaurus bones suggest that this sauropod's period of fastest growth occurred between about 7 and 13 years of age, when the animal gained about 32 pounds a day - or about 6 tons a year! Although paleontologists used to think that gigantic dinosaurs lived a century or so, based on studies of living reptiles like giant tortoises, growth rings show that their life span was probably a lot shorter, perhaps only 30-40 years.
Want to join the conversation?
- Could there still be dinosaurs on the earth that we just haven't seen or they are good at hiding(2 votes)
- thats not likely they are to big to hide forever(1 vote)
- would it matter what kind of dinosaur grows faster??(2 votes)
- yes because if a dinosaur grows bigger faster it gives them more time to have a proper defense against predators such as gigantosauras an argentinasuars will have to grow to 145 foot and 92 quicker, so a 50 foot gigantosauras can't eat them(1 vote)
- how do they live that long years along(2 votes)
- how much does a dinosaur egg takes to hatch?(1 vote)
- If these great beasts can live up to 28 years, then how come it's almost never the same age that battle, or bread?(1 vote)
- what are dinosaurs herds called(1 vote)
- It depends on the type of dinosaur.(1 vote)
- I've been watching "Jurassic Park" (scientific story). My opinion, today elephant, red wood tree in California grow huge as today. Prehistoric show dinosaur grow so large than today. My question is, does size of magnetic field of earth made Creature larger than today? Example, maybe larger or ultimate size of magnetic field made them bigger. Today, did magnetic field decrease size? Why we don't see any Creature large as Prehistoric? Should I ask NASA Scientific about changing size of magnetic field cause Creature change size?
I'm not a Scientific, like to learn more and read about it.
David Cox(0 votes)- they dont evolve to fast.the t. rex is a beast like that bro lol.they grow 28 years for battle(2 votes)
- I thank they live a long time a go. but it depends on what kind of dinosaurs it is depends on how long it lives(0 votes)
- i think. oh ya those beasts could grow to 28 years(0 votes)