Dolphins have long been hailed as some of the most intelligent animals in the known world, capable of complex social interaction that rivals that of even chimpanzees. Now researchers have revealed that not only do these animals enjoy cross-species friendships, but they can also enter complex alliances that last generations.

That's at least according to a study recently published in the journal Marine Mammal Science, which details how Atlantic bottlenose (Tursiops truncatus) and spotted dolphins (Stenella frontalis) regularly form mixed species encounters (MSE) and even actively share resources in Bahama waters.

This of course is not the first instance of observed MSE for either of these exceptionally communal species. Atlantic bottlenose dolphins, for instance, have been repeatedly spotted traveling and playing with humpback whales after a paper published back in 2010 was the first of its kind to record and scientifically assess the behavior. There is also mountain of anecdotal evidence that wild dolphins are willing to cooperate with humans - saving people from drowning or guiding them away from hungry sharks.

However, according to Cindy Elliser and Denise Herzing of The Wild Dolphin Project, this is the first instance of what can really be called an "alliance" between two species of dolphin.

The Project has been studying wild dolphins in the Bahamas for about 30 years, and in that time, Elliser observed these two distinct species travel, play, and forage together. (Scroll to read on...)

"They even babysit," she recently told New Scientist, describing how adult female spotted dolphins appeared to be caring for baby bottlenose dolphins for short periods on at least two occasions. Pregnant spotted and bottlenose dolphins even appeared to have their own expecting mothers circles, bracing for the challenge of calf-rearing that was just around the corner.

Overall, the researchers determined that the two dolphin species spend about 15 percent of their time together, every day.

And it's important to point out that the researchers are not calling this some sort of symbiotic relationship or silent agreement driven by biological needs. It seems, for all intensive purposes, an alliance born of friendliness.

Elliser added that it wouldn't be much of a stretch to assume that this kind of social, cross-species cooperation is born from a progression of high intelligence. After all, modern mankind has many complex forms of cooperation, and likely even formed alliances with the Neanderthals in its most primitive years. Who's to say that we're not witnessing a similar phenomenon among dolphins? One day, they too might be doing far more than simply asking the neighbors to mind the pup for a bit.

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