Many researchers agree that dolphins are extremely social creatures and actually depend on this interaction for hunting, mating and defending themselves and their pods.
Typically, dolphins live and travel in groups ranging from 2-40 dolphins. But scientists have found dolphin pods as large as several hundred members.
These groups are actually called herds or schools. In some cases, these larger groups have been to known to include more than one species that seem to interact well together.
The species that usually associate in this multi-species group are the Spinner and the Spotted Dolphins. As the feeding habits of these two species are quite the opposite, they are able to travel together without competing for food.
Lasting Relationships
Most experts believe that the social relationships formed by dolphins are actually long lasting and it has been reported that when dolphins meet other pods or groups, they often engage in a sort of greeting ceremony that suggests they are renewing old relationships.
While large groups of dolphins usually have a varied mix of age and sex, the smaller pods tend to be made up of either a single adult, male and female, a group of females and their young or a group of adult and young males. Males are dominant in all groups but there is no evidence of strong social bonds between males and females.
A common example of social interaction and high intelligence, is the constant play that dolphins seem to engage in. Scientists report that juvenile and adult dolphins often chase each other and toss items such as seaweed back and forth.
Day to day Relationships
Dolphins often have close body contact with other dolphins through rubbing, petting, and even hitting each other. Dolphins often swim extremely close to each other, often resting fins on the other dolphin. Scientists believe this behavior actually indicates a close friendship. Dolphins also have been watched rubbing pectoral fins as if this was a handshake.
Another way that scientists identify social interactions between dolphins is by their behavior. When aggressive, dolphins tend to approach from a direct or perpendicular line. When the approach is non-threatening, a dolphin usually comes from behind or in an oblique angle.
Communication, the ground for socialization
Dolphins communicate with their pods and large groups usually through whistles. Many scientists and dolphin researchers believe that each individual dolphin actually has a unique whistle that identifies him to other members of his pod or group.
Dolphins in distress seem to use a special whistle that indicates help is needed. The pod or group usually responds quickly.
Social activity beyond limits
While we seem to expect that dolphins should be socially involved only with their own kind, the dolphins’ interest in interacting with humans is clear.
In the wild, dolphins are extremely curious and they will often engage in contact with humans if a chance comes up. In captivity, dolphins are very attached to the people they usually interact like trainers or researchers.
The developed intelligence of dolphins, their advanced capabilities to communicate combined with their need for social interaction make dolphins a unique animal in the nature.
Killer Whales are one of the fastest creatures in the sea, traveling up to 30 miles per hour.
” Killer Whales eat up to 5% of their body weight every day. 
Dolphins have been interacting with humans for as long as we have known of their existence.