Otters squealing

I am still wondering why the otters were squealing the whole morning so went to do some research..

Source: Kidsplanet
How do sea otters communicate?
Through body contact, nosing one another, head-jerking and vocalizations. Sea otters, in comparison to sea lions, for example, are not extremely vocal animals. However, adults use a soft, low cooing sound, and grunts to exhibit "contentedness," among other things. Pups use a high-pitch squeal to communicate with their mom. Some other sounds in the vocal repertoire of sea otters include whistles, whimpers, squeaks, whines, growls, snarls and hisses.

hmm... were they hungry? in danger? am still puzzled...