Otters Who Live Alone Like to Talk

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By Kylie Wolfe

Chirp. Squeak. Growl. When an otter makes a sound, who’s around to hear it? The neotropical river otter (Lontra longicaudis), an endangered aquatic mammal, lives alone but likes to talk. These solitary creatures unite once a year during mating season, making it difficult to study their communication patterns or gauge population size.

Researchers at the University of Vienna decided to study neotropical river otters and listened in on their conversations. Their work was recently published in PLOS ONE.

Listen Up

The research team, led by Sabrina Bettoni, a bioacoustician at the University of Vienna, housed three pairs of orphaned male and female neotropical river otters at the Institute Ekko Brazil and recorded their vocalizations. They listened for unique calls, analyzed each sound wave, and observed the otters’ interactions. This combination helped them determine the number of distinct sounds the otters make and how they use those sounds.

Bettoni and her team identified six calls associated with different otter behaviors:

  • Chirps: They want attention
  • Squeaks: They’re grooming or playing
  • Chuckles: They’re begging
  • Growls: They’re defending their food or territory
  • Hahs: They’re curious
  • Screams: They’re fighting

“I was surprised to see that they have a rich repertoire,” Bettoni told Science. One might have assumed they’d be less vocal given their solitary nature.

This is the first time scientists described these vocalizations acoustically. They discovered frequencies of 90 to 2,500 Hertz and found similarities between this otter species and others. Neotropical river otters likely share a common ancestor with otters who make comparable sounds.

Until this study, scientists knew very little about neotropical river otter communication patterns. Though they’re often found alone, their chatter is still complex, just not as complex as other otters. Another isolated species, the North American river otter (Lontra canadensis), has four unique calls, but more social species, like the giant river otter (Pteronura brasiliensis), have up to 22 calls.

Look Ahead

Other scientists caution that the otter calls observed during the study may differ in the wild. Because this species usually lives alone, being paired with other otters for an extended period may have influenced their behavior.

Next, Bettoni wants to take a closer look at the evolution of otter communication. She hopes this research will help protect a declining neotropical river otter population that’s threatened by deforestation. Scientists may also be able to use these sounds to lure the otters long enough to record population data and aid conservation efforts.


Discussion Questions

  • What surprises you about this study and its findings?
  • Activity: Develop your own form of communication. What are the challenges associated with a new language or behavior?

Vocabulary

  • Aquatic Mammal
  • Endangered
  • Solitary
  • Vocalization