It ’s a uproarious party trick that never seems to get old . But scientist did n’t make an alligator inhale He just for scientific jokes : they require to rule out why these outspoken wight are so noisy .

Both males and females loudly inform the man of their presence twelvemonth - round using call option known as bellows , although they churn them out more frequently during the mating time of year . Such long - distance vocalizations have been known to channel certain forcible characteristic about the company , like sex and torso size , which is important for both courtship and territorial behaviour .

For exercise , incrocodilians – alligator , caimans , crocodiles and the gharial – females will only copulate with males that are larger than them . And males obviously do n’t want to go around pick engagement with Male that are substantially enceinte . So it makes sense that these animals would apply these vocalization to inform others of such features , but no one had actually look into this . In comes the helium .

The reason helium makes our voices go Donald   Duck   mode is that it ’s light than zephyr , which means that sound waves travel much faster through it and thus the frequency of sonority are increased . This does n’t really   alter the pitch , but ratherchanges the timbre .

The researchers used this feature of He to their advantage , recording the vocalization produced by a female Chinese alligator after breathe in either normal aura or a premix of helium and oxygen , heliox . Of course , this did n’t involve a balloon , but instead an airtight chamber .

Although the vocalizations really sounded deep in the heliox condition , after do an acoustic depth psychology on the recordings they discovered an upward shift in frequency . As reported in theJournal of Experimental Biology , this indicates that   the animals utilize resonances in the vocal piece of land , which have never been documented in non - avian reptilian before . The scientist therefore conclude that these vox could help to channel consistency size . And since birds and crocodilians share a unwashed antecedent with dinosaur , perhaps dinosaurs used alike communicating system .

[ H / TWashington Post ]