Dolphins have been a mystery and a source of fascination for mankind for thousands of years.
They may belong either to the more commonly known family Delphinidae, which includes all oceanic dolphins, or to the family Platanistidae, which includes the river dolphins.
There are more than 40 species of dolphins living throughout the world’s oceans and rivers.
These mammals vary greatly in size, with their length ranging from than 4 to 30 feet and their weight ranging from 88 lbs. up to 22,000 pounds .
These dolphins live off the coast of New Zealand, and the average adult weight of these small mammals is 88 to 132 pounds (40 to 60 kilograms).
They have an average adult length of 3.8 to 5.3 feet (1.2 to 1.6 meters).
Other small dolphins include Heaviside’s dolphins, which weigh 132 to 154 pounds (60 to 70 kilograms) and are about 5.6 feet (1.7 meters) long when they reach adulthood, and acrobatic spinner dolphins, which weigh 130 to 170 pounds (59 to 77 kilograms) and measure about 6.6 feet (2 meters) in length as adults.
Another small dolphin is the Indus river dolphin; as an adult, this dolphin weighs about 150 to 200 pounds (70 to 90 kilograms) and measures 7.5 to 8.5 feet (2.3 to 2.6 meters) in length.
The bigger, more moderate-sized dolphins include the popular bottlenose dolphin, which as an adult weighs 331 to 442 pounds (150 to 200 kilograms) and measures 6.6 to 12.8 feet (2 to 3.9 meters) in length, and the striking Pacific white-sided dolphin, which weighs 300 to 400 pounds (135 to 180 kilograms) and measures 5.5 to 8 feet (1.7 to 2.5 meters) in length when it reaches full maturity.
The Atlantic spotted dolphin, which as an adult weighs 200 to 315 pounds (100 to 143 kilograms) and measures 5 to 7.5 feet (1.6 to 2.3 meters) in length, is another dolphin in the middle-weight class.
One of the larger dolphins that is still called a dolphin in the common tongue is Risso’s dolphin, which is also known as Grampus.
This animal, which has been spotted offshore in both warm temperate and tropical waters worldwide, weighs 660 to 1,100 pounds (300 to 500 kilograms) and measures from 8.5 to 13 feet (2.6 to 4 meters) in length when it has reached adulthood.
Among the dolphins that are called whales is the short-finned pilot whale.
An adult can weigh anywhere from 2,200 to 6,600 pounds (1,000 to 3,000 kilograms) and can measure from 12 to 18 feet (3.7 to 5.5 meters) in length.
Finally, the largest dolphin is the killer whale, or orca.
An adult female orca can weigh in at a whopping 16,500 pounds, and the male can weigh up to about 22,000 pounds (a range of 7,500 to 10,000 kilograms).
Female orcas measure about 28 feet (8.5 meters) in length, and males are about 32 feet (10 meters) long at their largest.