In one episode, the family explores a cave. Papa mentions that cave bears (presumably intended to be an ursine version of cave people) may have once lived in the cave. Cave bears actually existed.
In an episode from the 2003 cartoon, Brother says he wants purple ketchup. It was a thing at one point — Heinz once ran a line of ketchup that came in different colors, with purple being one of them (and incidentally, the most known color among the ones offered).
Colbert Bump: The video games are experiencing this after The Angry Video Game Nerd talked about them, particularly Camping Adventure when Rolfe said it was a decent platformer worth checking out.
Edited for Syndication: The 80s series got hit with this pretty badly when it was in reruns in DiC's syndication package — the episodes were noticeably sped up and even with that, they were often edited down considerably for time.
Additionally, all logos and references to Southern Star and Hanna-Barbera were deleted and replaced with the "Incredible World of DiC" logo, apparently as an attempt to make it look like DiC made it themselves (Southern Star licensed the rights- H-B/WB no longer has any rights; and when Southern Star folded in 2013, Nelvana (producer of the 2003 series) got the rights to the 1985 series).
VHS releases of the 80s show also removed the cold opening episode previews before the theme song, removed the text at the end of the theme (it used to say "The Berenstain Bears Show" with credit to the original book authors), and also replaced the original title cards (the ones with the green background and the portrait of the family) with a shot of the Theme Tune Roll Call. On DVD, some episodes are presented this way, while others retain the original intro title screen and episode title card.
Neither adaptation has the complete run on DVD. There were a few releases, but they were randomly scattered five 11-minute segment volumes (two and a half episodes each). The 1985 series did get a few VHS releases, but they were exclusively episodes based on books (such as "The Messy Room" and "The Truth"). The entirety of the 2003 series can be found on YouTube at least.
While it's true that there's been no comprehensive season DVD set release of the 2003 series, as of 2016 there have been so many individual and compilation DVD releases of the series, mostly by Kaboom, that it seems very unlikely that there are any installments of the series that aren't on DVD. In particular, this cube set includes close to 50 stories from the show across 10 DVDs (there are one or two story duplications) and is probably the closest thing to a complete series set the show will have.
The 80s series is particularly screwed; even if you had every single VHS and DVD release the show ever had in your collection, you'd be missing nearly 21 segments total (10.5 30-minute episodes, basically). This is a good fifth of this show's entire run, and only two of these segments have ever been preserved on sites like YouTube. note These are "The Substitute Teacher" and "The Raid on Fort Grizzly."
Not the case as of 2017, as a decent amount of the 80s series has been posted on YouTube courtesy of this channel.
Recursive Adaptation: Some episodes of the TV series were eventually turned into books themselves - twice. Some were rewritten as Berenstain Bear Scouts chapter books, which of course led to some Adaptation Expansion.
Society Marches On: The story about Sister being bullied by Tuffy. Sister only gets away with a slap on the wrist - in the new tens, Sister would have been in just as much trouble as Tuffy.
Additionally, Tuffy is seen throwing rocks at a baby bird - that would easily put Tuffy in therapy today.
Throw It In!: According to Stan and Jan's son, the series title is this. They weren't intending on calling their characters "The Berenstain Bears". They only got that name because that's what their editor, Ted Geisel (Dr. Seuss) referred to them as, constantly, and the name just stuck.