Really excited to see this finally out! A couple years ago, graduate student Tracy Burkhard ( @ttburk) found that individual differences in the song effort of wild singing mice were correlated with individual differences in circulating leptin, a hormonal signal of fat reserves. https://twitter.com/animal_prattle/status/1293197385766768641

Erin Giglio ( @tweetingmouse) injected leptin to trick males into thinking they were heavier than they were, which led to even more singing.

This video by Bret Pasch shows what we mean by mouse song - a long, frequency-modulated trill.

Male singing mice use these vocalizations to attract females and deter rival males. A lot of work in animal behavior might lead you to think of song length as a kind of "honest signal" of body condition, and it may be. But this doesn't really show that.

Because another way to think of it is strictly from the perspective of the signaler. If singing more or longer has costs, a male may decide just how much he can afford. That's true whether females are using that information or not.

More recently, @ttburk found that song rate & body condition are moderately heritable, but the co-heritability is not particularly strong. We're writing it up now. Like this very minute. But you can see a talk on song h2 Tracy gave at @AnimBehSociety! https://twitter.com/ttburk/status/1288553126711242752?s=20

My student David Zheng has just finished a beautiful neuroanatomical study on the circuits of vocal control in singing mice. He finds that circuits of vocalization, social cognition and energy balance all coincide in the paraventricular hypothalamus.

In the language of neuroscience, we're hoping to understand how interoceptive & exteroceptive cues are integrated to shape behavior. In the language of behavioral ecology, we want to understand the mechanisms by which males balance trade-offs to match behavior to circumstance.

Either way, a lot of great people working on these projects, and it's a real joy to see them coming to fruition!