All posts by Jonathan Tweet

Crow Scientist in Persian

Crow Scientist is now available in Persian (Farsi)! In March, Nasser Yousefi of DONYA  Children’s Research Institute contacted Dr Marzluff about translating our app into Persian. The institute works on early childhood education and development in Iran. They have been working on a children’s crow project for some time, drawing kids’ attention to the lives of crows. Everyone loves crows! Now they have our app to help them with their valuable educational work. We hope that in this small way, our the shared love of children, education, and crows builds a connection between American and Iranian citizens.

Our developer, David Marques, would be happy to incorporate other languages into the app if others can provide the translated text. Which language will be next?

Crow Scientist teaches kids to observe crows the way a scientist does. Here in Seattle, you can hear young crows begging for food, so it’s a great time to show kids how to spot them. Learn more. Crow Scientist is free and ad-free! Get it here.


Since 2015, we have been creating imaginative ways for kids to learn about science, especially evolution. We are all related!

Grandmother Fish: A Child’s First Book of Evolution
Groundbreaking and delightful. Available from Macmillan through any bookstore. Ask for it at an independent bookstore near you (find a store). Hoot! Hoot! Learn more.

Clades & Clades Prehistoric
Animal-matching card games that teach evolutionary relationships among animals—including humans! A “clade” is any complete branch of the evolutionary family tree. Available direct from Atlas Games or ask for it at your friendly local game store. Learn more.

A “cladogram” of all the animals in Clades

Clades Solo
This app provides a one-player Clades experience—with dinosaurs. Learn more.

Crow Scientist
With this free app, kids learn to observe crows the way scientists do. Designed with crow scientists John & Colleen Marzluff. Learn more.

Planet Voyagers
This beautiful board game teaches kids about the solar system and Earth’s place in it. Available direct from SimplyFun.

Planet Voyagers Released

Planet Voyagers from SimplyFun

My new game Planet Voyagers engages players with its planet discs, which show the planets in scale to each other (full-size images on the reverse). Players play cards at the same time, so there’s no waiting for your turn. Special cards reference the statistics for the individual planets, such as length of the year or components of the atmosphere. Score points by moving down the row, by winning the research tokens associated with the planets, and by playing special cards.

The game comes from SimplyFun, which has created a beautiful game set based on my black-and-white prototype.

Outside the US, you can order Planet Voyager though

“Crow Scientist” is Live!

“Crow Scientist” is live on the iOS App Store, on Google Play, and on Amazon. Karen’s art is ready to go, and she’s taking some extra time to make sure we position the art the best way we can. An update in the near future will add the art. We could also use a couple 5-star reviews, if you’re so inclined.

We are still looking for people to give us feedback to improve the app. Get links and provide feedback on the publisher’s Crow Scientist page…

You can follow Colleen, the “Lead Crow Scientist”, on Instagram.



Beta Test the “Crow Scientist” App

We closed out our successful Kickstarter campaign two days ago, and our free app “Crow Scientist” is now in a public beta test. For this project, I worked with two crow scientists, John & Colleen Marzluff, and it’s turning out great. The programmer, David Marques, has a web page with links to the beta test for Apple and Android, as well as for submitting feedback, art, and photographs.

“Crow Scientist” App

You can also see more of “Crow Scientist” on Grandmother Fish’s Facebook page.

Grandmother Fish

Thanks for supporting evolution science for children.

Clades Solo with Dinosaurs

Karen and I have updated our mobile game, Clades Solo, with dinosaurs and better science notes. Now the app includes the extinct animals from the Clades Prehistoric tabletop card game. Play with either set of cards, or mix them together.


Google Play:

Amazon Kindle Fire:

Which two cards complete the triple with the dinosaurs?

Karen and I don’t have an advertising budget, so if you like Clades Solo, please tell a friend, a parent, or a teacher. Thanks.

Grandmother Images for Teachers

When teachers present Grandmother Fish to classrooms, it’s handy to have images of the five Grandmothers. Here are full-size images of the Grandmothers, each to be printed on a letter-size sheet of paper. Sometimes for a reading I have five different kids volunteer to act out the sounds and motions of one Grandmother each. In that case, each kid can hold the image of their Grandmother for the class to see. When I do timeline exercises, again I get five kids to volunteer to stand up and show everyone where on the timeline their Grandmothers lived. Now that I have these images, each kid will get one to hold.

Click on an image to get the full-size PDF.

From GRANDMOTHER FISH: A CHILD’S FIRST BOOK OF EVOLUTION. Illustrations © 2016 by Karen Lewis. Reprinted by permission from Feiwel & Friends. All Rights Reserved.

If you use these images in a classroom, Karen and I would love to hear about it. Enjoy!


Free Evolution Books for Teachers

Know any elementary school teachers in the US? How the Dormacks Evolved Longer Backs and How the Piloses Evolved Skinny Noses are two fictional books that demonstrate adaptation by natural selection. If you’re a grade school teacher in the US, you can click below to get free copies and teaching materials. These two great books come from the Evolving Minds Project, funded by the National Science Foundation. They feature evidence-based approaches to teaching evolutionary concepts to kids, grades K–5.

These people are also fans of Grandmother Fish. It’s wonderful to have evolution educators like the people at the Evolving Minds Project approve of our book.

Free books for teachers:

Evolution Resources

This post provides online resources for fans of evolution for kids, parents, and educators.


Books, Games, and Web Sites

When I was working on Grandmother Fish, I naturally looked around for other evolution resources that were already available.

Evolution: How We and All Living Things Came to Be, by Daniel Loxton. Ages 8–13.

Great book on the science of evolution. Loxton did the art as well as the text, so it all works together beautifully. Covers answers to common misconceptions and arguments against evolution.

Evolution: The Story of Life, by Douglas Palmer. High school to adult.

The sheer scope of this book makes it a must-have. Spread after spread is a full-color scene from prehistory, from the earliest suggestions of life to prehistoric humans. Page after page, you see the history of life on earth play out. It gave me a greater appreciation for the vast diversity of living things over the last billion years. The art isn’t flashy, but it’s effective, and there’s an insane amount of it. The writing is dense, and there’s nothing kiddie about the book, but it’s filled with illustrations and photos that kids would love to pore over. Best yet, in the US you can buy this $48 book used for under $10, including shipping.

Our Family Tree: An Evolution Story, by Lisa Westberg Peters. Ages 4–7.

This sweet picture book is a lot like Grandmother Fish, but for older kids and with more detail. It recounts our lineage starting with the origin of life itself. Science notes in the back provide a context for the lyrical story. It’s high on folks’ lists of good evolution books.

How How the Dormacks Evolved Longer Backs,
How the Piloses Evolved Skinny Noses,
Evolving Minds Project.

These fictional books explain natural selection and are free to elementary teachers in the US. Click here to learn more. Funded by the National Science Foundation

Great Adaptations, by Tiffany Taylor. Ages 8–12.

Illustrated poems describe ten evolutionary findings or concepts. After each poem is a description of the scientific work that it’s based on and the evolutionary scientist involved in that work. The one about the emotional connections among early humans is especially cute, and this poem’s art is also especially cute. Kids love illustrations of happy families. The rhyming nature of the stories means you can read them to younger kids.

Grandmother Fish, by Jonathan Tweet. Ages 3–6.

My passion project for 15 years, finally published. See my Grandmother Fish page.

Go Extinct! game, Ages 8+.

This card game is a variant on Go Fish uses our evolutionary family tree. Two hundred years ago, animals were categorized into broad groups, such as “reptile” or “bird.” Today we place each species on a continuously forking evolutionary line of descent, with each species related to the others according to what forks they share. The phylogenetic tree, as it’s called, is like the periodic table of elements except for species. And since it reflects evolutionary history, it’s complex and disorderly. Getting kids to play a game that familiarizes them with the evolutionary tree of life seems like a great way to get them thinking in evolutionary terms. There’s phylogenetic tree in Grandmother Fish, and kids respond strongly to it.

Clades & Clades Prehistoric games, Ages 6+.

Karen’s and my evolutionary card games. See my Clades & Clades Prehistoric page.

Understanding Evolution web site. For adults.

This academic site is where you turn for expert opinion. If you want to know what your kids should know about evolution at each age, this site will tell you. It includes links to all sorts of resources about evolution. A project of the University of California Museum of Paleontology and the National Center for Science Education.

National Center for Science Education web site. For adults.

This organization promotes greater understanding of evolution and climate change. It’s a fine advocacy site for adults, and it has plenty of resources for kids, too. They were a big help with Grandmother Fish.

PBS web site. For parents.

PBS is great for science and has an evolution site.
Here’s a high-school-level video that explains natural selection.
The Nova site has its own evolution page.

How to Teach Natural Selection to Children

Natural selection can be hard to understand because it doesn’t match human expectations of how things work. These notes are designed to help a layperson, especially a parent, explain natural selection to a child. Elaborate each point at your child’s level, and explain it a little at a time. A version of these guidelines appears in Grandmother Fish.

These notes are also available as a 1-page PDF (click here).


Descent With Modification

You might also be able to point out examples in your family of heredity and diversity.

Baby animals grow up to be a lot like their moms and dads.

A puppy grows up to be a dog, not a cat or a fish.

Babies grow up to be a little different from their parents.

Some differences make life easier, some make life harder, and some don’t matter. Differences just happen.

Over time, the differences add up, so animals today look very different from the mom animals and dad animals from a long time ago.


Artificial Selection

You can also use other examples besides dogs

Dogs look different from how dogs used to look a long time ago.

People who wanted big dogs picked big dogs to have puppies.

After a long time, their dogs were bigger than before.

Other people got different kinds of dogs, like small dogs or fluffy dogs.

All the different kinds of dogs come from one kind of dog that lived a long time ago.


Natural Selection

Natural selection works because some individuals leave many more surviving offspring than others do, who may die before reproducing or have few descendants for other reasons. These guidelines hint at death but don’t mention it. Address the topic in ways suitable to your children.

Living in nature is dangerous for animals.

Animals have ways to keep themselves safe.

Baby animals are born with differences, and some differences make them safer.

Animals that keep themselves safer have more babies.

A long time ago, one group of animals climbed trees to be safer, and the best climbers were the safest.

The best climbers had the most babies, who were also good climbers.

After a long time, these animals had evolved into animals that were really good at climbing trees.

In different parts of the world, animals found different ways to be safe, so they evolved into different kinds of animals.

For example, one sort of animal from a long time ago evolved into the lions, tigers, wolves, foxes and bears that are alive today.

Stated Clearly offers another good overview of natural selection
Stated Clearly offers another good overview of natural selection