Don't blame the dinosaurs
Scientists can compare the DNA of different creatures to get an idea of how long ago they had a common ancestor. This article explains how some scientists have compared the genes of mammalian species to figure out that mammals were already very deverse long before the dinosaurs went extinct. This is fascinating stuff-- a fascinating discovery and a fascinating way to have discovered it. People are pretty smart!
Sometime in the last few years, my girls and I invented a creature known as "the howling octopus". Any stories we make up involving the ocean, in any way, must include this invention. 
"It is theorized that the howling octopus is related to the North Sea Kraken"
Now, my girls do not know it is made up. In fact, a few weeks ago, my youngest said "Dad, I know the howling octopus is not real". I probed a bit and found out her buddies at preschool had spilled the beans. So I asked if she believed everything they said, and anyway eventually I convinced her (without outright lying, a skill i build at Christmas and other holidays) there still was such a thing.
Here is my daughters' current understanding of the beast (straight from their mouths):
OK, I promised I wouldn't just post reviews-- though this in a way is a review of biological handiwork in a way. Here is a little critter I ran into in a big fat Animal book my daughter Emma and I checked out. There are only 110 species of them in the world, and they are very strange creatures if you try to classify them. Though they look kind of like a millipede or a caterpillar, they are not arthopods at all. Arthopods (arachnids like spiders, crustaceans, insects and centipedes/millipedes) have segmented bodies and a chitenous exoskeleton. The velvet worms do not. From Wikipedia:
Onychophores are thought to be closely related to the arthropods. The structure of their brains is similar to spiders, raising the possibility that they are most closely related to arachnids, though molecular analysis contradicts this.
...
The similarity of these creatures to caterpillars is not purely coincidental; as with most creatures, the larval stage of moths and butterflies are thought to represent, however inconsistently, previous evolutionary stages. Arthropods are thought to have evolved from a multi-segmented animal not entirely unlike both onychophores and caterpillars. In fact, the characteristics of larval insects are part of the evidence cited to support models of insect ancestors, for example in justifying how many segments and legs such creatures were thought to have, many of which evolved into other parts on modern insects, like antennae and mouthparts.
