AbstractWhile several works analyzed the spatial learning and memory capacities in adults of subterranean rodents, no study was done examining the development of these cognitive processes in pups of any of those species. Therefore, the development of spatial working memory in the South American subterranean rodentCtenomys talarumwas investigated by analyzing the pups' spatial performance in a delayed alternation task. When a short delay of 1 min was interposed between runs in the Y‐maze, 20‐day‐old pups made more errors than 40‐ and 60‐day‐old pups. When longer intervals (10 min) were elapsed between runs, younger pups made approximately twice as many errors as the ones committed by 60‐day‐old pups, showing the age‐dependent development of spatial working memory in this species of subterranean rodent. Increased space use byC. talarumpups, caused first by the appearance of independent exploratory behavior and later by the need of leaving maternal territory and construct a new burrow system, showed some correspondence with the improvements in the pups' spatial working memory performance, suggesting for the importance of this cognitive capacity in developing pups for which spatial learning and memory constitute essential abilities for survival and fitness. Dev. Psychobiol. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 592–597, 2010.