# Learning to call



## rozdaboff (Feb 27, 2005)

I recall in an animal behavior course that I took several years ago, that experiments were done in certain bird species, where young raised in isolation of any adults took longer to develop their calls, and that their calls never achieved the complexity of calls of birds raised in the presence of adult birds of the same species. IIRC, the region of the brain responsible for the learning was the hippocampus (not entirely important in this discussion). The call "learning" was done at a very specific time in development, as hormones prepped the hippocampal region for learning.

So my question is this - does a similar phenomena happen in certain frog species? If one acquires froglets of one frog type, and no other adult frogs of that species are present the persons collection - do they begin to call at a similar age as frogs raised in the presence of calling adults?

As anecdotal evidence - When I acquired a my first pums, a very young group of CB basti froglets - there were obviously no calling adults in the collection. I had these frogs for a year or so before I acquired any more Pumilio. To this day, the frogs have very limited calling (2 males, 2 females) - and the call is not as well developed (although to me, it has seemed to be slightly improving since the addition of another Basti group with a calling male). However, one of my holdback Yellow-Belly pum froglets has begun to call (and quite well at that) at around 6 months of age. There has been at least one calling male Yellow-Belly in the frog room for the entire duration of froglet development. I know that some other Pum breeders with large frog rooms have observed calling at a very early age as well.

Any thoughts? Any research any one is aware of on the topic in Anurans?


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## Dancing frogs (Feb 20, 2004)

Very interesting...
I've thought of that, but never long enough to post about it.
An easy one to test would be imitator, mine usually start calling at around 3 months, give or take...and you don't exactly have to put a cup to you're ear to hear them.


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## Dancing frogs (Feb 20, 2004)

Not to change the subject, but this I would think is very closely related to what you are talking about...

If learning something as simple as calling is inhibited by not having a role model, could that also be why some pumilio F1's are not as good of parents as WC/FR?
I know it would take a huge tank (so as to no stress all frogs involved) to allow offspring to grow up to the point where they see eggfeeding behavior at a time in their life where they might remember how to do it when their time comes.
Might be worth a shot...
Oz, if you think this should be a separate post, go ahead and make it so...


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## Ed (Sep 19, 2004)

snip "I recall in an animal behavior course that I took several years ago, that experiments were done in certain bird species, where young raised in isolation of any adults took longer to develop their calls, and that their calls never achieved the complexity of calls of birds raised in the presence of adult birds of the same species. IIRC, the region of the brain responsible for the learning was the hippocampus (not entirely important in this discussion). The call "learning" was done at a very specific time in development, as hormones prepped the hippocampal region for learning. "endsnip

I have some serious doubts about this.. There are some incest avoidance studies coming out that appear to link the calling more to a genetic basis where the resemblence of the males calls were linked to thier relatedness allowing the females to avoid incest.. (see http://icb.oxfordjournals.org/cgi/conte ... ct/32/1/18 for the abstract and article if you have access) with variations in the calling being based on the genes. (more closely related males have more similar calls..) and in relation to the dear enemy phenomena (see http://adsabs.harvard.edu/abs/2005ASAJ..118.1879B) although this may be the person to ask.. http://www.biology.utah.edu/faculty2.php?inum=4

Keep in mind that sexual maturity in anurans can be very dependent on a number of factors particuarly nutrition.. and temperature which tend to be constants in the frog room allowing for maximal growth rates and early sexual maturity (sexual maturity is often related to size and body fat content in herps). 
I would suspect that the early calling is due to several things including the thought noted above but also due to the dear enemy phenomena. The frog has an unoccupied territory and a potential competitor begins to call nearby. Early calling in this case is advantageous as it allows for the frog to become "established" in its location allowing it to spend resources on growth and keeping it out for the new comer. 
(a slightly tangential article see http://www.blackwell-synergy.com/links/ ... 863.x/abs/) 

Learned parental rearing behaviors is only seen in animals that have family groups that last for several groups of offspring staying together (this is not seen in pumilio). What we maybe seeing in the F1 pumilios that there is evidence that younger parents do not put the same investment into rearing the offspring as older parents.. (for one example see http://links.jstor.org/sici?sici=0269-8463(200104)15%3A2%3C211%3ASADADI%3E2.0.CO%3B2-%23). 
Now I suspect that there are also other factors but given that this is a long-lived species I would expect to see improvement in parental rearing skills after several years... 

Some comments

Ed


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## melissa68 (Feb 16, 2004)

Oz,

I have read a few articles & seen a few TV specials discussing a similar subject. One piece of information I found interesting is birds will also have 'dialects' or 'accents'. They learn from the other birds they are around. If a bird is from KY, and another of the same species is from FL - studies of the voices have found differences in the calls. 

I thought it was cool at the time..



rozdaboff said:


> I recall in an animal behavior course that I took several years ago, that experiments were done in certain bird species, where young raised in isolation of any adults took longer to develop their calls, and that their calls never achieved the complexity of calls of birds raised in the presence of adult birds of the same species. IIRC, the region of the brain responsible for the learning was the hippocampus (not entirely important in this discussion). The call "learning" was done at a very specific time in development, as hormones prepped the hippocampal region for learning.
> 
> So my question is this - does a similar phenomena happen in certain frog species? If one acquires froglets of one frog type, and no other adult frogs of that species are present the persons collection - do they begin to call at a similar age as frogs raised in the presence of calling adults?
> 
> ...


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## bbrock (May 20, 2004)

melissa68 said:


> Oz,
> 
> I have read a few articles & seen a few TV specials discussing a similar subject. One piece of information I found interesting is birds will also have 'dialects' or 'accents'. They learn from the other birds they are around. If a bird is from KY, and another of the same species is from FL - studies of the voices have found differences in the calls.
> 
> I thought it was cool at the time..


The dialects can occur over much shorter distances. For example, the calls of cardinals in Topeka, KS are distinctly different from those in Lee's Summit, MO which is only about 70 miles away.


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## melissa68 (Feb 16, 2004)

Wow, I never realized dialects could be so different in such a short distance.

I wonder if the difference is noticeable to our ears, or if sound recordings need to be analyzed in order to hear the difference?


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## elmoisfive (Dec 31, 2004)

Oz,

No doubt you remember learning about some of the research on bird song and development performed by Fernando Nottebohm and colleagues at Rockefeller University. I know this work well because I was a graduate student there and remember attending a number of lectures about what was becoming, even in the 1980s, a very fascinating study of neurobiology as manifested in learning and development. One fundamental discovery is that isolated and socialized birds take different paths in terms of learning song.

http://www.sciencedaily.com/releases/20 ... 022530.htm

I don't know whether I would extrapolate these findings to frogs but it is somewhat interesting to speculate. One thing I've noticed with raising frogs (and it is very obvious because it will drive me nuts) is that oftentimes the young frogs of a species don't call at all while the adults of the same species are calling like crazy. Yet I'll send some of those offspring to another frogger and I hear that they started calling immediately upon arrival....almost as if the absence of the adult(s) calling let them tear loose.

Bill


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## kyle1745 (Feb 15, 2004)

I think there is a bit more to superiority or alpha male type activity in these animals than we realize. I have talked with some of the larger breeders over the years and many keep only pairs as it is the only way many species seem to breed regularly. This could also play into what you were saying about the offspring calling after they are separated from the parents.


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## Ed (Sep 19, 2004)

keep in mind that the frogs can gauge the size of potential competitors via the calling so young males may also be hearing the calls of the other males and "realizing" that they cannot compete with that one yet. 

The one thing I haven't seen commented on here is that there may also be a pheromonal or olfactory portion to this mix. People tend to think of dendrobatids as being strictly aural and visual but there is at least one paper that shows the ability to home based on olfaction. 

See Forester, D. C. and A. Wisnieski. 1991. The significance of airborne olfactory cues to the recognition of home area by the dart-poison frog Dendrobates pumilio. Journal of Herpetology. 25(502-504) 


The fact that they can do so may also indicate that there is some form of chemical communication going on between cages.

Ed


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## bbrock (May 20, 2004)

melissa68 said:


> Wow, I never realized dialects could be so different in such a short distance.
> 
> I wonder if the difference is noticeable to our ears, or if sound recordings need to be analyzed in order to hear the difference?


That little anecdote I gave about the 60 miles difference was an observation I made myself as a young teenager. The calls were noticeably different. Of course I had no idea this would be a scientific revelation. I just thougt, huh, birds have local dialects just like people.


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## bbrock (May 20, 2004)

Ed said:


> keep in mind that the frogs can gauge the size of potential competitors via the calling so young males may also be hearing the calls of the other males and "realizing" that they cannot compete with that one yet.
> 
> Ed


I can't resist interjecting a wolf anecdote here which is that wolves can judge the size of rival packs by their howls. But they also try to fake it. In a group howl, wolves will adjust their pitch to create a maximum of overtones which has the auditory effect of adding members to the howl. If a researcher howls at the same pitch as another wolf, the wolf will switch its howl up or down a half on octave to compensate and create an overtone.


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