In this study, the growth rates of a group of Galapagos giant tortoises raised in their natural habitat at the Charles Darwin Research Station (CDRS; Galapagos Islands, Ecuador) and a group of captive-bred specimens (Zoo Zurich, Zurich, Switzerland) were compared for the ﬁrst time. A great discrepancy in growth rates was observed after the ﬁrst year. When the animals were 4 years old, the carapace
in the Zurich specimens was approximately twice as long as that in the CDRS tortoises, and the Zurich animals weighed approximately 10 times more than the CDRS animals. The zoo diet was modiﬁed by a reduction in nutrients and an increase in ﬁber to produce a more natural growth rate.