text: Yo, check it out, here's the deal,
  We talkin' 'bout them marmosets, for real.
  Callithrix jacchus, that's their name,
  Captive adults, they play the game.
  
  In the home cage, they make a sound,
  Whistle-like "phee" calls all around.
  Territorial marking is what they do,
  Claimin' their space, showin' they're true.
  
  When they're separated, feelin' alone,
  Phee calls bring the group back home.
  More syllables in isolation, you see,
  Longer duration, set them free.
  
  Isolation calls, they got a twist,
  Shorter syllables, can't resist.
  Lower start and end frequencies they bring,
  Peak frequencies high, they make it sing.
  
  Frequency range, it's on the rise,
  More info revealed, no disguise.
  Context and location, they communicate,
  Isolated callers, they don't hesitate.
  
  When we look at the sexes, it's clear,
  Differences in call structure appear.
  Males go higher, they reach the top,
  Syllables varied, they just won't stop.
  
  Females hold it down, steady and true,
  But males bring the heat, that's their cue.
  Published in '93, Wiley-Liss, Inc.,
  Makin' knowledge drop, that's the hint.