Conservation news

Chirp, chuckle and growl: Neotropical river otters call out to communicate

Neotropical river otter by Sabrina Bettoni

Neotropical river otter by Sabrina Bettoni

  • Researchers observed and recorded captive neotropical river otters in Brazil and published the first formal description of their vocal repertoire.
  • Neotropical river otters make six sounds, characterized as chirp, squeak, chuckle, hah, growl, and scream, which are used in different social interactions.
  • The neotropical otter is classified as near threatened by the IUCN; otters were heavily hunted for their pelts from the 1950s through the 1970s which led to local extinctions, and although they’re now protected, they still face threats from poaching, habitat destruction, water pollution and mining.
  • Despite the limitations of recording in captivity, researchers say they hope that understanding more about otter vocalizations will help manage both captive and wild populations.

What growls, chirps, chuckles and swims in the swift flowing rivers of Central and South America? A new study reveals that neotropical river otters (Lontra longicaudis) have a rich repertoire of sounds that they use to communicate while fighting, playing, mating and more.

Researchers observed and recorded captive neotropical river otters at Projeto Lontra in Santa Catarina Island, Brazil, and characterized six distinct call types. Their findings, the first formal description of the neotropical river otters’ vocal repertoire, were published in the journal PLOS ONE.

A neotropical river otter in captivity at Projeto Lontra in Santa Catarina Island, Brazil. Photo by Sabrina Bettoni.

“It was wonderful to spend time close to these incredible and interesting otters, to learn about their vocal communication and be immersed in their daily life,” Sabrina Bettoni, a Ph.D. student at the University of Vienna, and the study’s lead author told Mongabay. “However, with the sounds from several animals, wind, water and blowing leaves, it was challenging to get a clear audio recording of the otters’ vocalizations.”

The six sounds were characterized as: chirp, squeak, chuckle, hah, growl, and scream, and are used in different social interactions. For instance, females may “squeak” during play, let out a “hah” when surprised, and “scream” when defending themselves or their food. Both sexes “growl” as a warning in conflict over food or space.

A Neotropical river otter “hah” vocalization recorded in captivity:

https://imgs.mongabay.com/wp-content/uploads/sites/20/2021/05/26002551/hah_call.wav?_=1

 

A Neotropical river otter “scream” vocalization recorded in captivity:

https://imgs.mongabay.com/wp-content/uploads/sites/20/2021/05/26002909/scream_call.wav?_=2

 

Researchers say the vocal complexity of the neotropical river otters lies somewhere in between the solitary North American river otter (Lontra canadensis), which has four call types, and the giant otter (Pteronura brasiliensis), a highly social species with 22 call types. Of the 13 known otter species, studies have been published on the vocal repertoire of six. Many of the call types used by the neotropical river otters were similar to the calls of other otter species.

Otters were heavily hunted for their pelts from the 1950s through the 1970s, with an estimated 30,000 otters killed each year, leading to local extinctions throughout their range from northwest Mexico to central Argentina. Although neotropical river otters are now protected in every country they inhabit, they still face threats from poaching, habitat destruction, water pollution and mining, and are classified as near threatened by the IUCN.  Most attempts to rehabilitate these otters via captive breeding have been largely unsuccessful.

Neotropical river otters live a mostly solitary life in the wild and have proven difficult to breed in captivity. They prefer swift, clear, flowing water and eat a lot of fish. Photo by Sabrina Bettoni.

Neotropical river otters are shy and more active at night, making them difficult to locate and study in the wild. They are considered solitary creatures (aside from mothers with their pups) and therefore frequently communicate via scent marking in the wild. Because the sounds in this study were recorded from a captive population, where otters were housed in pairs, they may not represent the full repertoire of vocalizations. The captive environment is likely altering some of the otters’ natural behaviors. For instance, the most frequently recorded sound in the study, the “chuckle,” was associated with otters begging for food from humans.

Despite the limitations of recording in captivity, the researchers say they hope that understanding more about otter vocalizations will help manage both captive and wild populations and benefit conservation efforts, providing an acoustic, non-invasive method for monitoring and censusing otters where they live.

The neotropical river otter. Photo by Sabrina Bettoni.

Citation:

Bettoni, S., Stoeger, A., Rodriguez, C., & Fitch, W. T. (2021). Airborne vocal communication in adult neotropical otters (Lontra longicaudis). PLOS ONE, 16(5), e0251974. doi:10.1371/journal.pone.0251974

Banner image of Neotropical river otter by Sabrina Bettoni.

Liz Kimbrough is a staff writer for Mongabay. Find her on Twitter: @lizkimbrough_

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