They all have 4 flippers, a layer of blubber and sensitive whiskers on the snout. But for my book on the legend/myth of The Seals Skin I am looking at Harbour Seals specifically.
Harbour Seals have streamlined fusiform bodies, tapered at both ends.
They have spotty coats and the dorsal side has more spots than the ventral side.
To move around it depends on its flippers. Fore flippers are short and webbed with 5 bony digits. The digits are about the same length, each has a blunt claw, around 1-2 inches. In the water the fore flippers are used for steering. The webbed hind flippers also have 5 bony digits, but the outside bones are longer and wider than the inside ones. Moving this side to side propels the seal. They are graceful swimmers although because their hind flippers do not rotate it makes them clumsy on land.
Tucked between the hind flippers is a tail.
They have short – thick hair which sheds in patches after mating season, this lasts 1-2 months.
Endothermic animals – meaning they control their body temperature by burning internal fuel, which also keeps them warm.
Mouth full of teeth – but not used for chewing. Front teeth are sharp and pointed, for grasping and tearing. Back molars used for crushing the shells of crustaceans and molluscs.
They can open and close their nostrils – pinniped. Relaxed nostrils are closed and airtight.
Lenses in their eyes are adapted for focusing on refracted light in the water. Pupils wide in dim light – closing to slits when bright. A reflective membrane makes eyes glow when hit with light.
Instead of ear flaps they have external ear openings to the ear canal. They opens and closes when they dive. They also have good hearing above and below the water, but respond better to sound in air.
Whiskers = Vibrissae, each move independently. They can detect the smallest vibrations and are very sensitive. The signals help navigation and finding food.
It is important to mention that I found this useful information/research at: oceantoday.noaa.gov/sealanatomy/
And that I have picked out the more relevant parts that correspond to my current work. There is much more on the website! But I hope you find it as useful as I do.