Fossils- Nature’s Time Capsules

Table of Contents

Do you love to solve puzzles? Are you willing to time-travel? Then pack your curiosity and get ready for adventure—we’re going fossil-hunting!


Fossils are all around us. They’re waiting to be discovered on beaches, in quarries, in state parks, even right under your feet. The La Brea tar pits bubble away in downtown Los Angeles, and paleontologists―scientists who study fossils―have found millions of fossils there, including mammoths, saber-tooth cats and dire wolves. So catch a bus, even skate-board, to your favorite fossil site!

What are fossils and what do they tell us?

Fossils, like time-capsules from the past, are buried clues to the big questions humans have been asking for ages. What plants and animals lived on earth millions of years ago? Are they the same or different to today’s?  [Did you know 50 million years ago horses used to be dog-sized?] Ancient catastrophes―meteor impacts, earthquakes and volcano eruptions―changed the planet. Life survived those times—what can fossils tell us about survival? Without fossils, we’d know almost nothing about the history of life on earth.


What prehistoric question most interests you?

How do you read fossil clues?

There are two general types of fossils―‘Body Fossils’ and ‘Trace fossils’. Both offer important clues.  


Body Fossils are the hard parts of plants and animals from long ago that have been preserved. Bones, shells, teeth, tree trunks—anything hard—can become a body fossil. Fossilization occurs over many thousands of years, transforming remains into a mineral copy of the original. Clearly, paleontologists have to be good sleuths, puzzling together so much of the past with just the hard parts of the full plant or animal. Some whole-body fossils have been found trapped in hardened tree sap, like insects, frozen in glaciers, or desiccated in the desert, but they’re rare.


‘Trace Fossils’ are clues left behind that provide evidence without the actual body. Animal footprints in ancient riverbeds are trace fossils that show size, stride length, and weight. Feathers and plant leaves can get trapped in sediments which harden over millennia―after the organism decays, a trace fossil impression remains in the stone.

Can you solve some famous fossil puzzles?

A fossil from 150 million years ago mystified paleontologists:

Was it a dinosaur or a bird? Fossil Archaeopteryx. Credit: H. Raab

Dinosaur or bird? What do you think?


Turns out, it was both! Archaeopteryx (pronounced: ar-key-OPT-erix) was a flying dinosaur with feathered wings. The fossil record is especially good at showing changes over time, or evolution. Archaeopteryx was an early species showing dinosaurs evolving into birds.


Suddenly paleontologists faced even more questions. And the fossil record provided answers. Do you know the answers?

Did other dinosaurs have feathers?


Yes! Paleontologists have since found many fossil dinosaurs remains with feathers, including a tyrannosaur relative of the T. rex.


Feathers suggest dinosaurs needed to stay warm, so were many dinosaurs warm-blooded?


Yes! Paleontologists recently analyzed fossil bone chemistry to show many, but not all, dinosaurs were warm-blooded.


Did birds evolve from dinosaurs?


Yes! So many similarities have been discovered between dinosaur fossils and modern birds, paleontologists agree that birds are directly descended from dinosaurs—something you may not want to mention at the dinner table this Thanksgiving.

Can kids make fossil discoveries?

Paleontologist Lisa White’s research sounds like a pirate adventure—she sailed the deep seas digging for treasure. But her treasures were tiny ancient fossils critical to understanding ocean currents. Now at the helm of the University of California’s Museum of Paleontology, she’s passionate about making fossils meaningful for young people, particularly minority youth. She brings fossils from her museum’s five million specimens to under-served classrooms around the San Francisco Bay Area, everything from dinosaur bones to teeny microfossils. She loves the racket in the room as excited kids make fossil discoveries.

Dr. Lisa White (left)—paleontologist at the University of California, Berkeley—has such an infectious enthusiasm for fossils, she’s been featured on NOVA and Bill Nye the Science Guy. Photo: Josephine Wu.

Dr. White brings students to remote fossil beds, too. A high-school student uncovered a hadrosaur jawbone on a Montana field trip. It became part of her museum’s collection, and the budding paleontologist—now enrolled at her university—shows off his fossil to friends.

You don’t even need to leave your chair to go fossil-sleuthing! Many of Dr. White’s museum fossils are online. Check out “Where the Wild Things Were”


Fossils are all around us, waiting for your curiosity. What prehistoric questions will you ask?

La Brea Tar Pits

Yes, the La Brea tar pits bubble. And the fossils found number in the millions. Accessed 8/29/2022.


Horse evolution

Among the best documented examples of evolution in all paleontology. Accessed 9/3/2022


Basic Fossil Types

Fossils 101. National Geographic. Aug. 22, 2019.

Accessed 8/10/2022


Archaeopteryx and the questions it raised

The first known dinosaur feather inspired decades of dispute. Here’s why. Michael Greshko. Sep. 30, 2020. National Geographic.

Archaeopteryx.   Accessed 8/26/2022.


Finally, You Can See Dinosaurs in All Their Feathered Glory. Knvul Sheikh. April 5, 2016. National Geographic.

Wiemann, J., Menéndez, I., Crawford, J.M. et al. 2022. Fossil biomolecules reveal an avian metabolism in the ancestral dinosaur. Nature 606, 522–526.


Paleontologist, Lisa White


Interviewed Sep 7, 2022.


White, LD, Garrison, RE, Barron, JA. 2007. Miocene intensification of upwelling along the California margin as recorded in siliceous facies of the Monterey Formation and offshore DSDP sites. Geological Society, London, Special Publications (2007), 64 (1): 429



Bones to pick: UC Berkeley paleontologist entices diverse students to dig her field. Molly Sharlach. August 6, 2014.  Accessed 9/1/2022.


White, L.,Bell, R. 2019. Why diversity matters to AGU, Eos, 100, Published 01 December 2019.


  • Jeanne Panek, Ph.D.
    Jeanne Panek is a research ecologist, nature adventure writer, and wilderness explorer. Her favorite part of science is the field work: radio-tracking jaguars in Peru, collecting clouds atop an Adirondack mountain, climbing trees in Yosemite to look for pollution injury. While doing science, she’s been charged by a mountain lion and piranha have nibbled her toes. In her free time, she searches for lost people in the mountains of California with her search-and-rescue team, plays mandolin and Minecraft. Jeanne believes the natural world is as magical as Hogwarts. She writes for Smore because she’s passionate about connecting kids with nature.

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