Communal suckling in the cavy Galea musteloides

We quantified the extent of communal suckling in the cavy Galea musteloides. Six groups of animals were held in large indoor enclosures and suckling behavior was recorded over 113 h of observation. The groups contained 2–6 lactating females and 3–14 sucking pups. Due to the relative synchronization of births, 73% of the pups present in each group during lactation were non-offspring. Each of the 22 lactating females in the six groups suckled non-offspring in addition to her own offspring. On average, females suckled 86% of non-offspring present in their groups. Thus, 98% of all pups (n = 47) received milk from non-mothers. Although suckling frequencies were significantly higher for mothers with their own individual offspring than with non-offspring individuals, females invested more total time suckling all non-offspring than did suckling just their own; this was possible because for each mother many more non-offspring than offspring pups were present during lactation. Suckling bouts were significantly longer for mothers with their own individual offspring than with non-offspring individuals. The proportion of non-offspring suckling of mothers correlated negatively with the proportion of own young among the pups of a group. Non-offspring suckling did not affect future reproduction of females. Our observations demonstrate extensive practice of communal suckling in G. musteloides under laboratory conditions. Probably because all mothers of a group participated more or less equally in communal suckling behavior, the obvious cost of giving energetically expensive milk to non-offspring did not result in reduced (future) reproductive success. Potential benefits directly involved with communal suckling are unclear. More indirectly, communal suckling as well as birth synchrony might contribute to the formation of advantageous multi-litter kindergardens.