The cartilaginous fish are so named because their skeleton is composed of cartilage which is not reinforced by the minerals that make bone. These minerals are only present in their teeth and skin. The class includes the sharks, sawfish, rays and chimaeras. The majority of them are marine, though a few do venture into brackish and freshwater.
Scientific name: Chondrichthyes
A comparison of cartilaginous fish size in relation to humans - from the 12m long whale shark to the 17cm dwarf lanternshark.
The following habitats are found across the Cartilaginous fish distribution range. Find out more about these environments, what it takes to live there and what else inhabits them.
Discover what these behaviours are and how different plants and animals use them.
Additional data source: Animal Diversity Web
Take a trip through the natural world with our themed collections of video clips from the natural history archive.
When it comes to summer holidays, there's no better place than the seaside and if you know where to look you'll be surprised at the wildlife you can find.
Watch the most memorable moments from an incredible career watching wildlife, chosen by Sir David from the BBC archive.