SCIENCE

Are mothers or the collective cacophony of the colony more effective in teaching young bats how to communicate? (National Geographic)

Go a little batty with our Creature Feature on nectar bats.

Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.

Discussion Ideas

• New research documents how bats learn distinct “dialects.” What are bat dialects?
  • Bat dialects simply describe the pitch of bat vocalizations. Bats vocalize with their larynx (voice box) and mouth, and sound is emitted through their mouth and nose. Although most bat vocalizations are pitched out the of range of human hearing, they can emit calls “as low as 50 dB and as high as 120 dB, which is louder than a smoke detector 10 centimeters from your ear.” Learn more about real-life bat signals with this great article from Scientific American.
    • FYI: In human language, a dialect describes a distinct variation of a language, usually marked by accents and grammar.

• What do bats use dialect and vocalizations for?
  • echolocation. Bats use high-pitched vocalizations to engage in echolocation, which helps them identify obstacles or objects (including predators and prey). This is an especially neat trick to have at night, when most bats are active. Take a look at this worksheet for an illustration of echolocation.
  • communication. When bats squeak, they tend to squabble. Researchers determined that most bat communication is arguing—over things like food, space, sleep, and mating. Learn more about bat communication here.

• How did researchers conduct their study of bat communication?
  • The experiment consisted of four major parts. Bat vocalizations were recorded and analyzed throughout the experiment.
    1. “[R]esearchers caught 15 pregnant Egyptian fruit bats and took them into the lab. To control for potential genetic effects, they ensured that the mothers weren’t closely related.
    2. “The team then split the mothers into three groups of five and put each group into one of three chambers, where the mothers gave birth to their young.”
    3. In addition to their mother’s calls, scientists piped in calls of wild Egyptian fruit bat colonies to the chambers. Each chamber had calls pitched to a different frequency—a different dialect.
    4. After 14 weeks, the bat mothers were released into the wild. (Don’t worry, researchers are also planning to release the young bats.)

• What were the results of the study? Did the baby bats sound like their mothers or the community?
  • As soon as they were six months old, “pups from all three groups had begun to communicate in the dialect that matched their recordings. This suggests that the background chatter of the colony is more influential on the pups’ communication than their mothers’ calls.”
    • After the young bats are released into the wild, researchers will track their calls to see if they change to match wild bat communities or whether wild bats pick up the experimental bats’ dialects.

• The crowdsourced method of learning a dialect is what researchers call “crowd vocal learning.” What other animals do researchers think might engage in crowd vocal learning?
  • Cetaceans, such as whales and dolphins, may learn distinct dialects through their communities. Learn more about how whales may learn to “speak” dolphin with our study guide here.
  • The authors suggest that pinnipeds (such as seals and sea lions) and may use crowd vocal learning to communicate across their large coastal colonies.
  • The authors suggest that some birds may use crowd vocal learning to communicate in large flocks or colonies.
  • Humans! It may take a village to teach a dialect. “If we can understand how bats do it, I think we can learn something about how humans do it,” says one scientist.

TEACHERS TOOLKIT

Nat Geo: How Baby Bats Learn to Speak in Dialects

Nature: How baby bats develop their dialects

Nat Geo: Featured Creature: Nectar Bats

Scientific American: How do bats echolocate and how are they adapted to this activity?

NPR: When Bats Squeak, They Tend To Squabble

(extra credit!) PLoS Biology: Crowd vocal learning induces vocal dialects in bats: Playback of conspecifics shapes fundamental frequency usage by pups