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Noon Edition

Saving Up For A Rainy Day

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Are you annoyed by that guy in your office who plays solitaire all day and never actually accomplishes anything?  Then you'd really be aggravated in the work environment of the Damaraland mole-rats of the Kalahari Desert, where up to forty percent of a colony is "that guy."

            These rodents live in underground burrows, and labor is divided among groups called castes.  This social structure is similar to ant colonies and beehives where a single queen aided by a few males produces offspring for the group.  Everyone else belongs to the worker caste that tends the young, maintains tunnels, and forages for food. 

            The worker caste is further subdivided into two groups -- frequent workers and infrequent workers.  Like the names imply, frequent workers labor continually and do ninety-five percent of the colony's work while infrequent workers mostly spend their days relaxing and getting fat on food their more industrious compatriots have collected.

            This seems like a raw deal.  Why do frequent workers tolerate these freeloaders?  Well, infrequent workers actually do pull their weight, but only when the time is right.

            The rock-hard Kalahari Desert soil is only soft enough to tunnel through following rainfall.  Therefore, during the one or two rains that fall each year, mole-rats must work overtime to build tunnels so they can reach nearby colonies with new mates.  When it rains, the infrequent workers quickly mobilize their extra fat stores and shift their metabolisms into high gear.  The extra energy conserved by lazing away may translate into a surge of burrowing power that exploits the softer soil in a way other colony members cannot.  Thus, laziness is really a clever strategy that helps the colony reproduce.

The Kalahari Desert.

Mole-rats in the Kalahari desert use laziness as a survival strategy. (Winfried Bruenken, Wikimedia Commons)

Are you annoyed by that guy in your office who plays solitaire all day and never actually accomplishes anything? THen you'd really be aggravated in the work environment of the Damraland mole-rats of the Kalahari Desert, where up to 40 percent of a colony is "that guy."

These rodents live in underground burrows, and labor is divided among groups called castes. This social structure is similar to ant colonies and beehives where a single queen aided by a few males produces offspring for the group. 

Everyone else belongs to the worker caste that tends the young, maintains tunnels, and forages for food. The worker caste is further subdivided into two groups of frequent workers and infrequent workers. As the names imply, frequent workers labor continually and do 95 percent of the colony's work while infrequent workers mostly spend their days relaxing and getting fat on food their more industrious compatriots have collected. 

This seems like a raw deal. Why do frequent workers tolerate these freeloaders Well, infrequent workers actually do pull their weight, but only when the time is right. The rock-hard Kalahari Desert soil is only soft enough to tunnel through following rainfall. Therefore, during the one or two rains that fall each year, mole-rats must work overtime to build tunnels so they can reach nearby colonies with new mates.

When it rains, the infrequent workers quickly mobilize their extra fat stores and shift their metabolisms into high gear. The extra energy conserved by lazing away may translate into a surge of burrowing power that exploits the softer soil in a way other colony members cannot. Thus, laziness is really a clever strategy that helps the colony reproduce.

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