Mae'r siarc main yma’n cael ei enw o'r pigau o flaen ei asgell ddorsal. Gall ddefnyddio'r pigau yma i amddiffyn ei hun drwy gyrlio mewn bwa a tharo ysglyfaethwr.

A dark, stocky warbler, the Cetti's warbler is most likely to be heard, rather than seen - listen out for its bubbling song among willow, marsh and nettles.

The porbeagle shark is a member of the shark family Lamnidae, making it one of the closest living relatives of the great white shark.

The birch polypore only grows on Birch trees. This leathery bracket fungus has a rounded, coffee-coloured cap that was once used for sharpening tools, hence its other name: the 'Razorstrop…

The thresher shark is a migratory species and passes through UK waters in the summer months. If you’re lucky, you might see this magnificent shark jump high out of the water in to the air.

Giants of the jellyfish world, these incredible creatures are the UK’s largest jellyfish! They can grow to the size of dustbin lids – giving them their other common name: dustbin-lid jellyfish.…

The pretty Deptford pink is a very rare flower that is very vulnerable to the loss of our traditional grassland and farmland habitats. It can only be found in a few places in England and Wales.…

A great way to get up close and personal with the magnificent osprey is via one of the many nestcams set-up in the places that it breeds: Scotland, Cumbria, Wales and the East Midlands.

With a silvery body, and purple, pink and bluish streaks down its flanks, the rainbow trout lives up to its name. Popular with anglers, it is actually an introduced species in the UK.

A handsome fish, the tench has olive-green flanks, powerful fins and distinctive red eyes. It can be found in lowland lakes and slow-flowing rivers around the UK.