What does a seal look like?
Pinnipeds - which are often generalised as seals are actually a hugely diverse group of fin-footed, semi-aquatic mammals, they vary in size and weight from the 1 m (3 ft 3 in) and 45 kg (99 lb) Biakal Seal to the 5 m (16 ft) and 3,200 kg (7,100 lb) Southern Elephant Seal which is also the largest carnivore.
Here is a Harbor Seal or 'Common Seal' a True Seal found along temperate and arctic marine coastlines of the Northern Hemisphere.
Families of Seals
The Pinnipeds comprise of the following families:
Odobenidae (the only living member being the Walrus)
Otariidae - the eared seals (Sea Lions and Fur Seals)
Phocidae - the earless seals (or True Seals)
There are 33 extant (alive) species of Pinnipeds and over 50 extinct species found in fossils.
Habitat
Seals are widespread however most species do prefer the waters of the Northern and Southern Hemispheres. They spend most of their time in water but come onto the land to mate, give birth, molt or of course to escape from predators.
Here is a great video of scuba diver Jason Neilus swimming with some very friendly seals in the Fearne Islands, UK.