Many animals, when they are young, beg to elicit food from their parents. This is commonly seen in birds, but can range throughout various animals. This begging is an interesting trait because it has a conflict of interest between the juvenile and adult: the juvenile gets free food, but at the cost of the adult. Begging eventually stops at a certain age, but the reason why begging stops has been questioned. Three hypothesis were proposed by Madden, et al.: 1) adults stop responding to begging calls, 2) young voluntary switch to foraging from being dependent on the adult, or 3) at a certain time, young cannot produce begging calls. Madden, et al. tested these hypotheses on meerkats, a cooperative breeding animal.From 2005-2007, free-ranging meerkats were studied in the Kalahari Desert in South Africa by Madden, et al. Playback experiments were used for testing these hypotheses and observations were recorded. They found that adults fed pups more when begging increases, regardless of age. They also discovered that pups stopped producing begging calls that stimulated adult feedings after 100 days. This finding, along with the observation that begging calls changed in structure in age, resulted in a conclusion that hypothesis number three was the most accurate. In many taxa, begging calls change with an increase in age. In meerkats, it was observed that calls become lower in peak frequency due to the growth in body size as age increases.
This finding is important in the study of the evolution of signaling in animal communication systems. With this knowledge, we can now study if the change in begging call characteristics also elicits less feeding by adults in other species.
Madden, J.R., Kunc H.P., English, S., & Clutton-Brock, T.H. (2009) Why do meerkat pups stop begging? Animal Behavior 78:85-89.
Posted by: Christine Rega (Group C, last blogging week)
This is really interesting. Did anything else change about the calls besides the frequency? Did the anatomy of the meerkats vocal structure change as they got older?
ReplyDeletePosted by Heather Gore
This is an interesting post. Did this result as a result of the cost to the adult who feeds the juvenile?
ReplyDelete-Posted by Sarah Benjamin
Hi Sarah and Heather,
ReplyDeleteTo answer both of your questions:
-They didn't note any other changes in the call other than the frequency, which makes sense because if the vocal cords lengthened (due to the change in body size) nothing else in the call would change besides the frequency. I'm not too sure what exactly physiologically changes when the meerkats age, it's just a guess on my part about the vocal cords.
-This change in feeding habits also didn't change due to the adult who feeds the juveniles. The change of the juvenile call results in the adults not responding. The adults don't stop responding due to the costs incurred when they feed their young.
Good questions!
Responded to by Christine Rega
This is a really interesting blog, How was the begging tested wit the meerkats? How were they able increase the begging in the older of the young meerkats?
ReplyDeleteEmerson Martin
This article was interesting because we saw an example of this begging for food in the gull video we watched in class. In this video the begging behavior in the young showed up again when the female was begging for food from the mate the she has chosen. I wonder if any calls or behaviors similar to the young meerkats begging showed up again later in their life? I know they are not able to make the calls once they get older but perhaps they do something similar?
ReplyDeletePosted by Tiffany Mallet