# Tadpole deposition behavior



## elmoisfive (Dec 31, 2004)

Since this came up in a different post and not wanting to sidetrack it, I thought I would start a new thread. My question is a simple one. To what extent does the male carrying the tadpoles determine the timing of their deposition.

I have seen situations where the male is takes the tadpole(s) to water and waits them out in terms of release. This can involve multiple trips to water and much patience on the part of the male. I will call this the "Tadpole Decides" situation.

However, I have also seen at times the male literally shaking them free from his back, almost reminding me of a dog shaking water loose from its fur. Perhaps they were just a little stuck there but it appeared that the male was encouraging them to leave. 

Then there is the case of my azureiventris male. For the first few clutches, he was depositing all 11-15 tads in one small water bowl (half coconut) over a 24 hour period. Subsequently though, he became far more selective and would only deposit 4-6 tads per water source. I became aware of this behavior because he had a clutch on his back and only deposited 5 tads in the coconut water dish. After waiting for a couple more days, I decided I needed to pull those tads and replace the water so I put a 16 oz deli cup about half full into the viv to let the water temp equilibrate. He then put 5 more tads in that cup. I waited 4 more days expecting that he would deposit the final 4 on his back into either water source but he didn’t. Finally somewhat exasperated with him, I removed the deli cup and replaced it with a fresh one. Literally within minutes he had jumped into the new deli cup and dumped his remaining tads.

Intrigued by this behavior, I have observed that he will initially go to a water source and allow between 4-6 tadpoles to slip off his back at which time he climbs out of the water. His departure is immediate and does not allow for further tadpole deposition. Even if there is another water source available he will ignore that for a couple of days and then deposit a few more once again climbing out after 4-6 have been released. I suspect that frogs aren’t good at higher order math which is why the number varies a bit. While could hypothesize that the tads sense something in the water like their fellow tads and stop hopping off, with the initial clutches they were perfectly happy to have all of them dumped in a common pool. So what would have changed to alter their behavior? 

I’ve seen this happen now over roughly 10 clutches so I don’t think it’s a fluke. If I have three water dishes in the viv, he’ll still take his time and do his distribution over the three sites in the course of 5-7 days. While I don't have him under 24/7 scrutiny, his viv is right next to my computer and I spend a fair amount of time observing that viv. I notice no visits to the water except when tadpole deposition is occurring. 

The morphing pattern of the froglets mirrors this staggered deposition in having three waves of froglets coming out of the water over the course of roughly a week. In fairness I haven’t tracked individual tads to see if the ones deposited first are the first to morph out. Perhaps a good experiment to run.

I have discussed this strange tad deposition behavior with a European hobbyist and his azureiventris only deposits a single tad per water source. Very odd when you consider that the frog is carrying a large load of tads.

So what do I call this behavior? "Dad Decides"? It seems too deliberate to be happening by accident. I realize that this runs counter to the conventional wisdom but I'm pretty certain the male is at least partially deciding when and where the tads are being deposited.

Bill


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## Guest (Feb 16, 2007)

Have you tried larger deli cups. See how many he puts in to those? Or smaller deli cups. And are you sure they can't count? If nature says you gotta count to survive, why not? But its probably more to do with hormones in the water that the tads detect. Good observations.


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## elmoisfive (Dec 31, 2004)

Cesar,

If I put in 4 oz cups containing ~ 1.5 oz of water he'll still deposit 5 tads. I have not gone larger than 16 oz. If there is a chemical detection going on, why would 11-15 tads in roughly 3 oz of water (the coconut dish) be acceptable at first? Also, how would tadpole sensing drive the sequenced deposition over a week? I don't have answers, just observations.

Bill


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## kyle1745 (Feb 15, 2004)

Im wondering if they instinctively spread them them out to help increase the possibilities that a predator may not get them.


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## kleinhanz (Oct 18, 2004)

Or, if they are anything like their parents, the tads will quickly eat all available food in the pond. Spread them out to maximize tad-to-available food ratio.

Just a thought. I love your observations BILL!!


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## sbreland (May 4, 2006)

kyle1745 said:


> Im wondering if they instinctively spread them them out to help increase the possibilities that a predator may not get them.


That seems like a pretty strong arguement. More often than not animals of all kinds are driven by instinct and the will to breed and multiply, and if spreading them out means more of a chance to get at least one group through without predators getting them, then it's probably engrained in them.


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