In an adorable video recently posted on YouTube, fishermen rescue a baby dolphin after it becomes tangled in a plastic bag. The Brazilian anglers pull the struggling calf aboard with a net and free it from the material before returning the dolphin to the ocean off the coast of São Paulo.
After the dolphin is cast overboard the small boat, the calf appears to happily jump out of the water, leading some to speculate that the behavior was actually an expression of gratitude. (Skip to about 1:45 in the clip above.)
The mammal's little "dance" may indeed be a form of non-verbal communication; another dolphin approached divers for help in an astonishing act caught on film earlier this year. However, dolphins are known to jump out of the water for a variety of reasons -- from accelerating travel to removing pesky parasites.
Whether this dolphin was actually jumping for joy is still up for debate, but either way, the fishermen's close encounter is pretty striking.