This theme first came up in Baxter's short story “Sheena 5”; see [Variety SF](http://variety-sf.blogspot.in/2007/10/stephen-baxters-sheena-5-when-humans.html) for a review, which is much more about the squid and less about the humans.

> A squid will have her mind genetically enhanced to make her smart, & to make her communicate with humans [...] she got pregnant just before the trip. Since she is smart, she gave birth in space in a way that hid the fact from mission control for too long. Now her craft is on asteroid, the rocket is fitted to asteroid & pushing it towards earth, but she has too many babies in her too small a habitat!
>
> Turns out 4 of her babies are very smart; rest are typical dumb squids. Dumber ones will get eaten by their smarter siblings. But soon, the life support starts getting overstretched. [...] Not only have the squids made their little asteroid wholly habited, they have ships all over Sol! Reinmuth is headed to earth, & humans are afraid. Near end, we will see hints of the doom of humanity - as nuclear attack against Reinmuth fails, & it's entering earth's atmosphere. Sheena 46 appears to be in charge.