Communication in the Giant Otter

The information below comes from Duplaix (1980), Chanin (1985), Harris (1968), Otternet, and Frankfurt Zoological Society Giant Otter Project.

Non-Vocal Communication

Giant Otters give few visual cues. Their small ears, lack of erectile hair and short legs to not lend themselves to it. Their eyesight is good, though, and they do recognise each other at distances of up to 50m, possibly by their distinctive throat markings.

Olfactory communication is important. When otters meet again, even after separations of only a few minutes, they touch noses, perhaps to sniff each other. As well as sprainting, they use musk from their anal glands. The marking is done at the campsites, being trodden into the substrate, and also on well-used pathways on riverbanks.

Vocal Communication

Giant Otters are extremely vocal. A group of otters produces a constant stream of screams, wails, barks, explosive snorts and the otter "Hah!", with many intermediates. These are warnings, contact calls, summonses from the alpha female to hunt and so on. Harris (1968) also mentions growls, and a call note like the buzzard Buteo. All the sounds are loud and produced with great force, so as to carry across bodies of water - people tend to interpret this as anger and aggression when there may be no such intention on the part of the intensely curious otters.

At least nine vocalizations are recognised, of which analysis is still in its infancy. The descriptions below are a summary of the findings in Duplaix (1980).

  1.   Hah!: this is a kind of question mark sound, indicating the lowest level of alarm or interest. Other otters briefly stop and look for the cause.
  2.   Explosive Snort: This is a high intensity alarm. All other otters stop what they are doing and regroup.
  3.   Wavering Scream: typically given during bluff-charges, or if meeting otters not from their group on the river.
  4.   Growl: low intensity offensive threat - can escalate into a high intensity staccato scream, or reduce to a hum-growl with closed mouth.
  5.   Hum: reassurance close contact sound as individuals travel together.
  6.   Coo: close contact call between mated pair or parent and cub. An excited friendly greeting.
  7.   Whistle: a rarely heard pure tonal sound. Used when groups of otters meet.
  8.   Cub Squeaks: made by baby cubs. Parent replies with a soft humming purr when the cub is very young, but with hums and coos later.
  9.   Cub Whines and Wails: nasal whines escalating up to shrill, piercing screams. Only the parents respond. Cubs use these for all levels of defensive annoyance and pain, food-begging, when lost and so on.
Giant Otter