Varies
Eel-like
About 24 cm (9.4 inches)
Small, compact body with long legs and toes
39-47 cm (15-19 inches)
Small to medium-sized diving duck
10-11 inches
Small and sturdy
12 to 18 inches
Small to medium-sized
10 to 12 feet
Large and muscular
Up to 7 cm
Flattened, conical or limpet-shaped
5.5 to 6.5 feet
Large, muscular
12-14 centimeters
Slim and streamlined
6.5 - 8.5 feet
Stout and muscular
Up to 120 feet (36.6 meters) with tentacles
Umbrella-like
Up to 40 cm (16 inches)
Tall, compressed body with large pectoral fins and long spines
Up to 23 feet
Streamlined with long neck and paddle-like limbs
4 to 6 feet
Slender and cylindrical body with a relatively short tail
3.1-3.9 inches
Small and compact
30-33 cm
Up to 13 meters
Large and robust
Varies depending on species, ranging from a few centimeters to several meters.
Varies depending on species, can be slim and elongated, or stout and stocky.