A case of "death by fur-ball" in a
young Freshwater Crocodile (Crocodylus
johnstoni).
Raymond Hoser
488 Park Road, Park Orchards, Victoria 3114
email: adder@smuggled.com
Originally Published in 2006 in Herpetofauna,
36(2):122.
Crocodiles in Australia are rarely kept by private hobbyists and as a result relatively little has been published on their captive husbandry and problems arising in private facilities.
Upon acquiring a "reptile demonstrator's licence" from the Victorian Government on 6 February 2004 I found myself under pressure to have a crocodile for education purposes.
One measuring about 27 cm total length was acquired on 29 June 2004 and housed in a heated tub with what I ascertained to be all the essential requirements.
As my prior keeping experience with these animals was nil, I consulted with keepers at crocodile parks in northern Australia, several experienced keepers in Melbourne (allowed to keep such reptiles under their permits) and also all the available literature.
The crocodile apparently thrived. It was taken to displays at Schools and elsewhere and seemed quite able to do shows on a daily basis, including being handled by numerous people, without sign of stress or ill-health, feeding almost as soon as it was placed back in it's tub at my facility.
On about 17 September 2004 the crocodile appeared "off colour" in that it's eyes were not being held open fully and it lost appetite. It did not feed. Non-feeding continued, but on 23 September 2004 the crocodile regurgitated it's last feed (from 16 September 2004). On the next day (24 September) it was found dead in it's cage.
In consultation with others, I reviewed my keeping practices and found no obvious identifiable fault, or cause of death on my part.
Speaking with other keepers of crocodiles I was advised that sudden death in young crocodiles was not unheard of, some keepers saying it appeared to be common.
I wasn't satisfied with this explanation and remained of the view that every death must have a cause.
The crocodile corpse that had been retained was subsequently opened up on 31 September to reveal a huge hardened oval shaped mass of fur (as in a fur-ball) measuring over 3 cm long and filling most of the abdominal cavity. This could be readily felt on the dead animal before it was cut open. This undigested fur-ball had clearly formed a blockage that had eventually caused decomposition of food later eaten and eventually death. The photos taken of the fur-ball were taken after the fur-ball had been cut up to show it's contents (fur) and don't indicate it's true ovoid shape as first seen.
In the early stages of keeping the crocodile it was fed a variety of food items, but it showed a major preference for rodents and to that extent it was fed what I had a good supply of and found easiest. That was the legs of mice that were pulled off before the mice (dead) were being fed to captive snakes.
The fur ball was clearly consisted of the sheets of fur present on the leg sections and evidently hadn't been digested, regurgitated or passed.
Hence the formation of the fur-ball had been inevitable and death likewise. (By contrast, snakes seem to eat and pass this material without problem).
Since this port-moretom, other keepers have mentioned their crocodiles either passing or regurgitating hair from rodents, although in the main this has been with larger crocodiles.
As a result of this diagnosis a second crocodile of similar size acquired on 16 October 2004 was fed on a diet excluding any rodent hair. Rodent legs fed, always had the hair stripped off. As of June 2005, this second specimen remains in perfect health.
As a result of these differential outcomes all keepers of crocodiles are warned to take care in terms of feeding rodents or other hairy foodstuffs to smaller specimens due to their apparent difficulty or inability to digest, pass or regurgitate such items.
Finally, following a review of a draft of this paper Scott Eipper drew my attention to Dunn (1981) which cited a case of four young C. johnstoni at Melbourne zoo (out of a total of four) dying from fur impaction after being fed on a diet of rodents. This further indicates the incompatibility of rodent fur and young C. johnstoni and implies it may be a common but often undetected problem in other collections which may fail to properly autopsy dead reptiles.
Reference
Dunn, R. W. 1981. Captive Reproduction in Crocodylus porosus and C. johnstoni. Pp. 104-106 in Banks, C.B. and Martin, A.A. 1980. Proceedings of the Melbourne Herpetological Symposium. Zoological Board of Victoria, Parkville, Victoria, Australia: 199 pp.
Acknowledgements
Brian Barnett (Victoria), Adam Britton (NT), Scott Eipper (Victoria), Adam Elliott (Victoria), David Heading, Brad McDonald (NSW), Peter and Judy Whybrow (Victoria) all gave valuable advice in terms of housing and husbandry for the crocodiles. Licences for the movement and possession of the said animals were provided with expediency by the South Australian and Victorian wildlife authorities and this was appreciated.
