Last updated: 12 September 2026
You should be able to check where every important fact in a KidzFeed guide came from. This page explains which sources we use, which we never rely on, and how we keep them up to date.
What each guide lists
Guides written to our current standard end with a Sources section of three to six sources. Each one has a short note saying what it supports, for example “the bell’s weight, the tower’s height and the clock’s dimensions”. Other official pages are linked in the text, next to the fact they support.
Some older guides do not have a Sources section yet. We add one whenever we bring a guide up to standard.
Sources we use
- Government and public science agencies, such as NASA, NOAA, the US National Park Service and the US Fish and Wildlife Service.
- Universities and research centres, such as the National Snow and Ice Data Center.
- Museums, zoos, libraries and archives, such as the Smithsonian and San Diego Zoo Wildlife Alliance.
- Scientific journals, when a study is the original source of a finding. Our polar bear guides cite research published in Nature Communications.
- Conservation and specialist bodies, such as the IUCN, Polar Bears International, the Giraffe Conservation Foundation and the Barn Owl Trust.
- Reference works with named editors, such as Encyclopaedia Britannica, and Guinness World Records for records.
Sources we never rely on
- Other children’s fact websites and content farms.
- Answers from AI chatbots, and summaries at the top of search results.
- Wikipedia as the only source for a claim. It can help us find the original source, which is what we cite.
- Anonymous posts, forums and social media.
- Any page we have not opened and read.
- Companies selling something, unless the fact is about their own product. If we use one, we say so.
When sources disagree
Trusted sources sometimes give different answers. The US Fish and Wildlife Service counts 19 groups of polar bears, and Polar Bears International counts 20. When that happens, we give both figures and say who says what.
When scientists or historians are still arguing about something, we say that too. We would rather tell a child “nobody knows for sure” than guess.
Keeping facts current
Some facts change. Animal populations are counted again, and new discoveries overturn old ideas. We put a year on figures that move, such as “about 26,000 polar bears (2023)”, and we check for newer figures when we update a guide.
One example: our giraffe guide said about 117,000 giraffes were left in the wild. That was the 2020 estimate. The 2025 count is about 140,700, and the guide now says so.
Checking links
We check the links in our guides with an automated link checker. Some trusted websites block automated checkers, so we open a blocked link by hand before treating it as broken. When a page has gone for good, we replace it with the publisher’s current page or an equally trusted source.
Pictures
New pictures come from our own media library or from public collections that allow reuse, such as NASA’s image library and the Smithsonian’s Open Access collection. Every picture must show what its caption says.
Know a better source?
If you know a more reliable or more recent source for something in a guide, please tell us through our contact page. If you think a fact is wrong, our corrections policy explains what happens next.