“…We predict that in the wild, where a large proportion of the diet of lion tamarins is made up of invertebrate and vertebrate prey which require practice and skill to locate and capture [Kleiman et al, 1986;Peres, 1989;Rylands, 1989;Carvalho et al, 1989;Passos, 1992Passos, , 1997Valladares-Padua & Prado, 1996;Albernaz, 1997;Dietz et al, 1997], the proportion of food received from others would be higher. This is supported by Passos [1992,1997], who reported frequent sharing of large prey (e.g., frogs and beetles) with infants in wild black lion tamarins, and also by data from golden lion tamarins [Ruiz-Miranda et al, 1999] showing that 51% of transferred items were prey, including orthoptera, phasmids, amphibians, and lizards. These high quality items are difficult for infants to acquire without assistance, because infants are both physically immature (prey items may be relatively large and "strong") and inexperienced (some prey items require practice and skill for effective location and capture).…”