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.
What about size?
As with determining their weight determining the overall size of dolphins can be a difficult task because there are numerous species and each species of dolphin has characteristics that make them unique from other dolphin species; however we can look at a couple of the dolphin species to give you a general idea of these differences in regards to size and weight.
The smallest known dolphin is Maui’s dolphin which is known to grow to lengths of around 5 1/2 ft. at full maturity and weigh slightly over 100 lbs..
This dolphin is an extremely rare species of dolphin that can be found near the shore of North Island in New Zealand.
In comparison the largest known dolphin is the killer whale which can grow to lengths of up to 30 ft. long and weigh as much as 12,000 lbs..
Unlike Maui’s dolphin the killer whale can be found throughout various oceans around the world.
While not always the case size can have a direct influence on where dolphins can be found living throughout the world.
For example some smaller species of dolphin can be found traveling in and around coastal waters where they are less likely to face threats from potential predators while larger dolphins may venture out further into the offshore ocean far from coastal waters.
Predators for the dolphin species may include killer whales and sharks; and yes killer whales do hunt other dolphin species for food.
Size can also play a role in the dolphins ability to stay warm in cold climates.
Larger species of dolphin are better able to displace heat throughout their body while using fewer calories to do so.
Killer whales for example (the largest of the dolphin species) can be found traveling throughout the Arctic and Antarctic waters while Maui’s dolphin and the popular bottlenose dolphin prefer to stay in warmer climate waters.
In addition to staying near coastal environments small dolphins are also known to travel in large groups in order to protect themselves from predators.
Depending on the dolphins species dolphins are known to consume anywhere from 2% – 10% of their body weight in food on a daily basis.
Lastly, size does not always determine the types of food a dolphin is likely to eat.
While it is true that the killer whale can consume a variety of marine mammals as well as fish and squid, most dolphins stick to a diet that consists of fish, squid, octopus and various crustaceans regardless of their size.
Since all dolphin species possess echolocation they can use this highly important ability to navigate the ocean, search for prey and get an early warning sign for nearby predators looking to turn them into a meal.
By combining their excellent sense of hearing with the use of echolocation dolphins are both excellent hunters and navigators making them one of the most advanced aquatic animals alive today.