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.

Freshwater pearl mussels spend their adult lives nestled in the river bed of fast flowing, rocky streams, filter feeding the water.

The papery, translucent, silver 'coins' of Honesty are instantly recognisable. They are actually the leftover seed pods that dangle from the plant through winter.

A climbing plant of hedgerows and woodlands, White bryony produces greenish flowers in summer and red, shiny berries in winter. It is a poisonous plant.

Tansy is an aromatic plant of rough grassland, riverbanks and verges that has button-like, yellow flower heads. It is the main foodplant of the rare Tansy Beetle, now found at only two places in…

Found in compost heaps and under stones in gardens, the flat-backed millipede is a common minibeast. It is an important recycler of nutrients, feeding on decaying matter.

A breeding bird of fast-flowing, upland rivers, the grey wagtail can also be seen in lowland areas, farmyards and even towns in winter.

The whinchat is a summer visitor to UK heathlands, moorlands and open meadows. It looks similar to the stonechat, but is lighter in colour and has a distinctive pale eyestripe.

Found on rocky shores and seabeds, the Keyhole limpet gets its name from the little hole at the tip of its shell.

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