It's called "Sharks" and is in the Usborne Discovery series. A really, really great series of books, well-written, well-researched, well-illustrated, pitched at the perfect level for an inquisitive toddler. And the "Sharks" volume is a fine example of the series. Loads of fascinating information, brilliant photographs, great diagrams. So what's my problem with it?
LittleBear's favourite section, to which I am firmly directed every time we read the book is entitled "Pup producers" and has the following paragraph:
A baby shark starts to form when a sperm cell from a male shark joins together with an egg inside a female shark. Before this can happen, a male shark has to push sperm into a female's body using a part of its body called a clasper. The sperm enters the female's body through a hole called a cloaca. This is called mating.
Now, normally my vocal stylings verge on the animated. The speed of the Mako Shark! The peril of a Tiger Shark attacking baby albatrosses! The extraordinary jaws of the Megamouth Shark! But there is no end to the monotony and subdued expression of my voice as I read about a shark's cloaca. There is no length to which I will not go to make the physical details of Selachimorpha intercourse sound utterly tedious, humdrum and not even slightly worthy of any questions whatsoever.
I am, quite frankly, not ready for conversations about cloaca, nor whether other animals have such a feature. I am certainly not interested in any curiosity regarding the presence or absence of a cloaca about my own person. And I am definitely not ready for any other questions involving eggs and sperm, and Mummy and Daddy. Ideally I'd leave it for another 16 years or so.