Concern about feeding mice/other vertebrates to tarantulas


Apr 10, 2009
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I have been wondering about this for some time now. Mass produced feeder mice/rats/other vertebrates are generally raised to support the reptile and herp. keepers. I don't think feeder mice and rats are specifically produced to feed tarantulas.

Here is where I am going with this. Mouse colonies to be maintained in a healthy state are likely given some form of medications whether it be in a supplement form as prophylaxis or in a treatment form for an outbreak of parasites (and parasite outbreaks do happen). If these antiparasitic medications contain chitin synthesis inhibitors as some flea preparations do, might this be the cause of some unexplained T. blondi molting misshaps?

T. blondi and kin from the genus Theraphosa seem to have a high occurence of wet molt, abdominal malformations/ruptures, cheliceral, leg malformations etc. The problems often occur when the spider is large enough to consume mice. A large individual T. blondi may consume many mice/rats in it's lifetime that have been subjected to antiparasitic medications during their time with the colony.

I have raised T. blondi in the past and limited their intake of mice because of these concerns.

I welcome input from anyone who has an opinion or further knowledge of this as I believe this may be a legitimate concern.

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Apr 11, 2010
Its hard to say, because even people that have never fed there T's mice get bad molts. Someone would actually have to have 2 groups of the same species kept under the same condition and feed one group mice and feed the other invertebrates to see what the difference may be. As far as I know, this has never been done.
All I can add, is that I've fed mice to many of my T's in the years past at the rate of no more than one mouse per molt & never had a bad subsequent molt. Never had a theraphosa though, so I cant attest to that.
So I would conclude that the antiparasitic medications do not effect the molts, unless of course there is not enough in one mouse to actually do any harm. At least not in non-theraphosa species. Multiple feedings could be different, as I have never attempted this.


Jan 9, 2011
commercially a lot of bad things are done to mouse/rat colonies which is why i grow my own home grown organic rodents i've been keeping them for years and have never had any health issues with the rodents so they've never had to be given medication this is in part to a healthy organic diet and clean enclosures if you keep their tanks clean and give them good food they don't get sick simple as that. with that being said commercial rodents could in theory cause said issues with theraphosa's or any tarantula given rodents i have yet to ever give my T's rodents and don't honestly know if i ever will i have 2 dubia roach colonies when my salmon pink birdeaters get bigger i'll just give the more roaches instead of rodents. but the only way to truely prove any theory is to do a study on them I.E have several theraphosa's (all from the same source would be best) and half of them feed rodents and half don't and study the affects. It could be that theraphosa's simply have molt issues but it could also be that rodents help cause them theres really no sure answer to your questions other than yes it could be a cause but like a lot of things with tarantula's theres not enough studies done yet for definite proof one way or another.