Re: how big is the crocidiles heart

Hi Shannon,

Thanks for your interesting question - it was quite difficult to find an answer for you. I suppose one answer would be "it depends on the species of crocodile, the size and whether it is an adult or a juvenile". Since you are in Queensland, I guess you are interested in the saltwater crocodiles (Crocodylus porosus) and freshwater crocodiles (Crocodylus johnstoni) that we have in Australia.

I managed to find an article written in 1994 by a couple of scientists at the University of Queensland. They were studying how the heart functions in juvenile saltwater crocodiles and they mention in their paper that for these small juveniles (which were only about 1 kg mass), the heart was about 3 g, or about 0.28% of the body weight. Now, as you know adult crocodiles can be very large (several metres long), but it is rare for an adult male saltie to be longer than 5 metres and such an animal would weigh 400 - 500 kg. So if we assume that the relative mass of the heart is the same in adults as juveniles, we can guess that an average adult crocodile heart might be about 1-2 kg in mass. That would probably be about the size of a rock melon or a bag of sugar.

This is only an estimation though - I could not find an exact figure, but I think this is a good guess. By the way, crocodile hearts are very interesting because they have 4 chambers like bird or mammal hearts and are unlike most reptile hearts, which have only 3 chambers. Here are some interesting links for you:
http://www.flmnh.ufl.edu/natsci/herpetology/brittoncrocs/csp_cpor.htm
http://www.ideacenter.org/contentmgr/showdetails.php/id/1113
http://savanna.ntu.edu.au/information/ar/ar_CR.html